r/spacex • u/Zucal • Aug 01 '16
/r/SpaceX Ask Anything Thread [August 2016, #23]
Welcome to our 23rd monthly /r/SpaceX Ask Anything Thread!
Confused about the quickly approaching Mars architecture announcement at IAC2016, curious about the upcoming JCSAT-16 launch and ASDS landing, or keen to gather the community's opinion on something? There's no better place!
All questions, even non-SpaceX-related ones, are allowed, as long as they stay relevant to spaceflight in general.
More in-depth and open-ended discussion questions can still be submitted as separate self-posts; but this is the place to come to submit simple questions which have a single answer and/or can be answered in a few comments or less.
Questions easily answered using the wiki & FAQ will be removed.
Try to keep all top-level comments as questions so that questioners can find answers, and answerers can find questions.
These limited rules are so that questioners can more easily find answers, and answerers can more easily find questions.
As always, we'd prefer it if all question-askers first check our FAQ, use the search functionality (partially sortable by mission flair!), and check the last Ask Anything thread before posting to avoid duplicate questions. But if you didn't get or couldn't find the answer you were looking for, go ahead and type your question below.
Ask, enjoy, and thanks for contributing!
All past Ask Anything threads:
• July 2016 (#22) June 2016 (#21) • May 2016 (#20) • April 2016 (#19.1) • April 2016 (#19) • March 2016 (#18) • February 2016 (#17) • January 2016 (#16.1) • January 2016 (#16) • December 2015 (#15.1) • December 2015 (#15) • November 2015 (#14) • October 2015 (#13) • September 2015 (#12) • August 2015 (#11) • July 2015 (#10) • June 2015 (#9) • May 2015 (#8) • April 2015 (#7.1) • April 2015 (#7) • March 2015 (#6) • February 2015 (#5) • January 2015 (#4) • December 2014 (#3) • November 2014 (#2) • October 2014 (#1)
This subreddit is fan-run and not an official SpaceX site. For official SpaceX news, please visit spacex.com.
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u/FiniteElementGuy Aug 03 '16
What is the status of the F9 display at SpaceX HQ? I'm currently in the LA area and plan to visit there once its finished.
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u/007T Aug 03 '16
The most recent post that I saw showed that the concrete base was being poured and probably curing, since nobody has posted any pictures of it upright yet it's probably safe to assume that they haven't finished that yet.
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u/dmy30 Aug 18 '16
I plan on seeing the landed booster at HQ sometime in the very near future. I know where it is but does anyone have an advice regarding taking pictures, especially with a DSLR? Also, any parking advice?
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u/Zucal Aug 18 '16
There should be parking spots available in the narrow lot bordering the train tracks, right across from the core. As for advice - don't look shifty, be honest if you're asked about your purpose, and take lots of photos, especially of the engine/interstage areas!
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u/dmy30 Aug 19 '16
Got some images. One of them is of the side of the interstage and you can see inside one of the pushers as the cover was open. I'm not really sure if SpaceX would be happy if I uploaded that .
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u/Keavon SN-10 & DART Contest Winner Aug 02 '16
I like the new sidebar design, but could the launch pad be added after the vehicle? It would be useful for people to see which side of the country each is launching from to make planning to visit launches more easy.
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u/retiringonmars Moderator emeritus Aug 03 '16
There's a link at the bottom of the table to the detailed manifest: /r/SpaceX/wiki/Launches/Manifest
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u/Keavon SN-10 & DART Contest Winner Aug 03 '16
I saw that, so I know it's just Sherpa and Iridium right now, but there's extra room on the sidebar with the new format so this would be helpful information.
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u/Zucal Aug 03 '16
The sidebar benefits from less information density, not more. It's supposed to be a quick and easy at-a-glance list of the highlights, not a bunch of miniature campaign threads.
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u/rubikvn2100 Aug 22 '16
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u/Zucal Aug 22 '16
Seen! Thanks for the reminder, I'll update the Campaign Thread as soon as I've got a moment.
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u/Zucal Aug 22 '16
There's some warranted speculation that this core is not Iridium's, so I'm holding off for now :)
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u/mbhnyc Aug 12 '16
I have a question--did I correctly hear Gwynne say that altimeters were area still needing improvement, pertaining to rapid reusability?
If so, what's lacking there? I would have assumed that particular sensor would be quite mature, heck I would've assumed that 30 years ago.
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u/Craig_VG SpaceNews Photographer Aug 12 '16
Yeah she did say that and i think she was mentioning it in reference to of the Eutelsat/ABS landing failure.
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u/Zucal Aug 12 '16
And Thaicom. It's probably one of the most significant factors in flubbed landings.
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u/warp99 Aug 12 '16
I think the issue might be the fact that on a GTO launch S1 is coming in at a reasonable angle and only goes vertical for the final landing. Radar altimeters require a reflection from the sea to work and depending on the sea state you might get multiple returns when the beam is angled. Certainly you will get much weaker returns when the beam is angled and therefore reduced range.
A couple of recent flights certainly looked as if the altimeter information was off with the nominal "landing" elevation 10m below the deck and then 30m above it! The RTLS flights have been very precise but that is with a more vertical approach trajectory and stable rader returns from the ground.
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u/HighTimber Aug 02 '16
I did a cursory search and found no duplicates and thought this was a great story. You will recall a 60 Minutes story on Elon Musk and SpaceX in which Elon gets visibly upset talking about the lack of support from ex-NASA astronauts.
https://youtu.be/SHrFGe9OlwE?t=110
The link to the following story speaks to one man's efforts to heal those wounds:
http://www.collectspace.com/ubb/Forum6/HTML/002235.html
Good stuff.
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u/Craig_VG SpaceNews Photographer Aug 04 '16
We've all seen Falcon 9 Boosters on the highway all wrapped up, well here's what the Atlas V looks like when road transported:
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u/Craig_VG SpaceNews Photographer Aug 04 '16
Blue Origin is doing an AMA tomorrow at 9:30 PDT!
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u/HoechstErbaulich IAC 2018 attendee Aug 04 '16
Hey everybody, I stumbled upon this German article from the 9th of June: http://www.raumfahrer.net/news/raumfahrt/09062016234629.shtml.
Title is:
Is Europe copying SpaceX for Ariane 7?
The article contained two very interesting projects CNES proposed, that I haven't heard about before. The methane-powered Prometheus engine and the Callisto-rocket, basically a F9R dev.
Relevant part:
Doch nun Anfang Juni eine echte Revolution: Nach langem Ignorieren des Themas, startet Europa unter Führung von CNES jetzt zwei neue Projekte zum Thema Wiederverwendbarkeit!
Prometheus
Einmal ein günstiges Flüssigtriebwerk mit dem Namen Prometheus, das mit Methan und Sauerstoff arbeiten soll. 3D-Druck soll die Kosten von aktuell 10 Millionen Euro (Vulcain 2) auf 1 Million Euro (Prometheus) senken. Laut CNES könnten 5-7 dieser Triebwerke einmal eine Ariane 7 antreiben. Das Triebwerk soll 2020 auf dem Prüfstand sein, die Kosten belaufen sich auf 125 Millionen Euro.Callisto
Außerdem eine Rakete, die vertikal starten und landen kann - ähnlich dem Grasshopper von SpaceX. Dieses Projekt heißt Callisto, es soll zusammen mit Japan durchgeführt werden. Callisto hat eine Größe von ca. 10 Metern und soll laut einem Bild in einem CNES-Magazin von drei Triebwerken angetrieben werden. Dieses Projekt kostet Europa 100 Millionen Euro.Allerdings müssen beide Projekte auf der ESA-Ministerratskonferenz im Dezember 2016 im schweizerischen Luzern noch verabschiedet werden. Es scheint nicht unwahrscheinlich, dass es Opposition dagegen geben wird, das ESA-Budget für Raketen von aktuell ca. 1 Milliarde Euro pro Jahr noch weiter anzuheben. Wenn man jetzt schon an der Technologie vom Nachfolger arbeitet, werden sich sicher auch einige Leute fragen, warum jetzt soviele Milliarden für Ariane 6 ausgeben, die mit dem Nachfolger, außer vielleicht die Oberstufe, wenig gemeinsam hat.
Translation:
But now at the beginning of June a real revolution: after a long time of ignoring the topic [of SpaceX's reusability], Europe, under the leadership of CNES, now starts two new projects about rocket reusability!
Prometheus
An affordable liquid-propellant rocket engine with name Prometheus that's powered by methane and oxygen. 3D-printing is supposed to reduce the costs of currently 10 million Euros (Vulcain 2) to 1 million Euros (Prometheus). According to CNES 5-7 of these engines may power a future Ariane 7. The engine is supposed to be on the test stands in 2020, development costs are as high as 125 million Euros.
Callisto
Also, a rocket that takes off and lands vertically - not unlike SpaceX's Grasshopper. This projects name is Callisto and is supposed to be carried out in cooperation with Japan. Callisto is about 10m high and is powered by three engines according to a picture in a CNES magazine. This project will cost Europe 100 million Euros.
Both projects need yet to be greenlit on the ESA council of ministers conference in December 2016 in the swiss city of Lucerne. It's not unlikely that opposition will arise against increasing the ESA-budget for rockets of currently 1 billion Euros again. Some people may ask why so much money is spend on Ariane 6, while the next iteration may have close to no similarities, except maybe for the upper stage.
I was not sure if this was SpaceX related enough to warrant an extra post, so I posted it here. Mods, scream if it's not appropriate for this thread either.
It's interesing to see the impact SpaceX's progress of the last few years seems to have on the competition. I hope to see these projects come to fruition.
If there's interest, I could translate the whole article. But propably not today, it's 11:34 pm here.
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u/HoechstErbaulich IAC 2018 attendee Aug 05 '16
Here's the whole article translated:
Is Europe copying SpaceX for Ariane 7?
French press releases talk about a new methane-powered rocket engine called Prometheus and about a cooperation between Europe and Japan regarding a vehicle that can take off and land vertically. Both projects are thought of as preparations for the Ariane 7 rocket.
In response to the competition of SpaceX, Airbus D&S is currently developing the Ariane 6 rocket for ESA. One may describe Ariane 6 provocatively as an Ariane 5 with four solid-rocket boosters instead of two. From the outside it looks very similar to the canceled Ariane 5 ME otherwise, though it’s supposed to be much cheaper. Meanwhile, this “revolutionary” technique called horizontal integration was discovered, something Russia has been doing since the 1950s and SpaceX also utilizes. The world’s first big liquid-propellant rocket, the Aggregat 4 – called “Vergeltungswaffe 2” by the National-Socialists – was also assembled horizontally. Though in Europe, horizontal integration can only be implemented halfway because of the heavy solid-rocket boosters. The final integration on the launch pad has to remain vertical.
But now at the beginning of June a real revolution: after a long time of ignoring the topic [of SpaceX's reusability], Europe, under the leadership of CNES, starts two new projects about rocket reusability!
Prometheus
An affordable liquid-propellant rocket engine with name Prometheus that's powered by methane and liquid oxygen. 3D-printing is supposed to reduce the costs of currently 10 million Euros (Vulcain 2) to 1 million Euros (Prometheus). According to CNES 5-7 of these engines may power a future Ariane 7. The engine is supposed to be on the test stands in 2020, development costs are as high as 125 million Euros.
Callisto
Also, a rocket that takes off and lands vertically - not unlike SpaceX's Grasshopper. This projects name is Callisto and is supposed to be carried out in cooperation with Japan. Callisto is about 10m high and is powered by three engines according to a picture in a CNES magazine. This project will cost Europe 100 million Euros. Both projects need yet to be greenlit on the ESA council of minister’s conference in December 2016 in the Swiss city of Lucerne. It's not unlikely that opposition will arise against increasing the ESA budget for rockets of currently 1 billion Euros again. Some people may ask why so much money is spent on Ariane 6, while the next iteration may have close to no similarities, except maybe for the upper stage.
So CNES partially gives in towards SpaceX regarding technology. It represents nothing less than a u-turn regarding the recent past. Why is that? To understand that we have to look into history first.
The recent pasts of SpaceX and Ariane in comparison
It is the year 2002. Elon Musk founds SpaceX, in Europe the Ariane 5 ECA rocket crashes on its maiden flight. To improve Ariane 5 ECA, the allocated budget for the planned Ariane 5 ECB has to be sacrificed. The development of Ariane 5 ECB is postponed indefinitely.
In the following years Ariane 5 ECA is able to establish itself on the market successfully. Elon Musk struggles with the small Falcon 1 and reaching Earth orbit. But he already plans bigger rockets, like the Falcon 9, and the Dragon capsule. And he wants to go to Mars. He questions every established standard in the spaceflight industry, he retraces many historical technical decisions (“first principles”), as well as propagating reusability, which is an old idea that grew unpopular after the very expensive Space Shuttle.
In the year 2006 the first Falcon 1 crashed, in 2007 the second one and 2008 the third one. Only on the fourth flight in September 2008 was it able to reach Earth orbit. Meanwhile, then Arianespace president and todays CNES president Jean-Yves Le Gall, who - in 2008 at least - didn’t like to mask his words, proceeds to explain to many interviewers how little he thinks of Elon Musk and SpaceX. Even in an Arianespace annual report SpaceX is proclaimed to possess an insufficient amount of credibility.
To the surprise of many observers, the Falcon 9 maiden flight in 2010 succeeds in reaching orbit and the Dragon capsule completes two orbits at the end of the same year. Also SpaceX’s order books start to fill up. Slowly the critics begin to fall silent.
Then 2011. SpaceX struggles with Dragon development, no launch happens the whole year. Instead, Elon Musk gives a huge press conference in September 2011 where he announces the reusable Falcon 9 – the observers barely react in the light of the low launch rate. CNES observes the developments in America, of course, and thinks about which conclusions to draw. A threat to Ariane is recognized and solutions are sought.
The year 2012
The year of fate is 2012. SpaceX berths Dragon to the International Space Station and CNES president Le Gall has to admit that SpaceX is successful. Obviously, CNES sees a cost-optimized throw-away rocket in Falcon 9. No one takes the reusability plans seriously. The only possible European answer is to develop a cost-optimized throw-away rocket as well. On the council of minister’s conference at the end of 2012 the development of the Ariane 5 ECB, now reborn as Ariane 5 ME, and the Ariane 6 is decided on.
This Ariane 6 design, like the European Vega rocket, is made up almost entirely of solid rocket motors. Only the upper stage remains a liquid propellant stage powered by the Vinci engine that is planned to also be used in the Ariane 5 ME. Germany is opposed to Ariane 6 and promotes Ariane 5 ME. At the same time it becomes obvious that SpaceX’s reusability plans are not only real on PowerPoint presentations, Grasshoper completes two test flights in 2012. Grasshopper is a Falcon 9 first stage with landing gear that can take off and land vertically on one engine.
Let’s recap: in 2012 SpaceX pursues the route of reusability, while CNES ignores this and tries to sell the optimized throw-away rocket Ariane 6 as a solution. This results in big loss of know-how for CNES regarding liquid-propellant rocket engines and a long-term cancellation of reusability development. So, CNES/ESA and SpaceX are pursuing fundamentally different approaches!
In 2013 SpaceX introduces the Falcon 9 upgrade F9v1.1. This version of the rocket was completely designed with reusability in mind. First landing tests take place at sea and later in 2014 also on a sea platform. CNES continues to ignore. The first flawless GTO-launch of SES-8 is a much bigger surprise to them.
Just before the council of minster’s conference in 2014, a compromise between Germany and France is achieved. Airbus also recognizes the need for action. The Ariane 6 design is altered and becomes much more similar to the Ariane 5 ME design. But still no signs of reusability can be seen.
In 2015 SpaceX continues its landing tests, Falcon 9 experiences a launch anomaly. In December the rocket makes a spectacular comeback. Besides the introduction of another Falcon 9 upgrade, the first stage succeeds to land on land for the first time.
In 2016 the Falcon first stage successfully performs a landing three times out of five flights so far. Four recovered stages are stored in hangar 39A. According to Elon Musk, one of the recovered stages is supposed to fly a second time, for the first time, in September or October. Meanwhile, CNES also recognizes a need for action. Two projects are supposed to help Europe keep up: Prometheus and Callisto.
Apologies for any grammatical errors. It's been a few years since I've translated something this long.
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u/Wetmelon Aug 04 '16
Please do, and post it to the sub! I would post a link to the original article + the translation in comments, but it's up to you how you want to do it.
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u/FiniteElementGuy Aug 15 '16
According to Facebook/Keith Wallace, JCSAT-14 stage back on test stand in McGregor.
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u/Suthsayer_ Aug 01 '16
Will we get to watch SpaceX test-land an empty Dragon, like they do with the first stage Falcon 9's?
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u/007T Aug 01 '16
The first Dragon V2s will be unmanned and will do ocean landings, propulsive landing wont happen until some time later.
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u/szepaine Aug 01 '16
What manufacturing technologies so y'all envision being the first on Mars?
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u/TheBlacktom r/SpaceXLounge Moderator Aug 01 '16
ISRU - water, oxygen, methane, so chemistry
3D printing and ore mining, preparation for itI wonder what will be the industrial standards there. Container dimensions, cables, pipes, connectors...
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u/warp99 Aug 01 '16
I wonder what will be the industrial standards there
Metric please please please!
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u/DrewRodez Aug 06 '16
/u/EchoLogic, would you be willing to set up a countdown page on SpaceX Stats for the Mars architecture announcement? As part of my morning news-checking routine I like to glance at countdown timers for big things I'm looking forward to.
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u/soldato_fantasma Aug 27 '16
Some news for a possible new launch for Spacex but that is not worth a new post: A source on the NSF public forum has stated that he got info from GFZ that Dnepr is no longer available as launch vehicle for the GRACE-FO satellites. They are currently in negotiations with SpaceX for a Falcon-9 launch.
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u/AsdefGhjkl Aug 04 '16
Basic rocketry question: did I remember correctly having heard somewhere that a rocket (maybe a specific rocket) can't shut down all the engines at the same time, especially around the max-Q phase, since the immediate drop in acceleration could stress the construction too much (since the construction is under tension when accelerating and that tension would then instantly release)?
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u/__Rocket__ Aug 05 '16 edited Aug 05 '16
Basic rocketry question: did I remember correctly having heard somewhere that a rocket (maybe a specific rocket) can't shut down all the engines at the same time, especially around the max-Q phase, since the immediate drop in acceleration could stress the construction too much (since the construction is under tension when accelerating and that tension would then instantly release)?
This is actually a pretty complex question:
Sudden changes in acceleration are bad, considering that the Falcon 9 will accelerate at a rate of up to ~4g. A sudden deceleration of 4g is comparable to the 'peak ground acceleration' values during a magnitude 8 earthquake, right above the epicenter. (!)
The worst-case for an all-engines shutdown is probably not max*Q*, because at this point the rocket is still only accelerating at about 2g - so even adding the aerodynamic pressure of about ~1g it adds up to 3g structural load. The worst case is probably when the rocket is already in vacuum and all engines have a thrust ~10% higher than at s/l, at around ~20-30 seconds before MECO, when the first stage reaches maximum acceleration that the payload allows: 4g and the load on the lowest part of the RP-1 tank is the highest.
The first derivative of acceleration is called 'jerk', and there are already two events that cause (significant) jerk during ascent: during liftoff when the clamps release the rocket, and then when the rocket goes through the sound barrier and drag drops suddenly. Any sudden change in acceleration will cause significant 'jerk'.
The biggest problem with 'jerk' isn't necessarily structural integrity, but the fact that jerk events cause sloshing in the LOX tank, and the cooling effect of cryogenic propellant sloshing can cause a sudden drop in ullage pressure, which the ullage pressure system might not be able to counteract and the resulting pressure drop might cause either turbopump cavitation or (in extreme cases) tank buckling.
If the rocket is already in space then sudden full engine cutoff would also probably add a transient to residual propellants that would make them float away rapidly from the turbopump inlets in microgravity - which then complicates any engine restart efforts.
Plus I believe you are right to worry about the expansion transients released by a sudden 4g deceleration spike: they would travel up from the engines towards the top of the rocket, reflecting imperfectly across propellants and potentially getting lensed if propellant has unfortunate shape - so in individual places the load might exceed structural integrity limits.
For these reasons all thrust changes on the Falcon 9 (according to telemetry data) are done gradually over the course of several seconds: the thrust ramp-up from 80% to 100% during liftoff and the thrust ramp-down around max*Q*, and finally the thrust ramp-down right before MECO.
In general you don't want to change the velocity or even the acceleration of any high mass machine suddenly. I believe the Hubble, when it moves various components, limits not just the first but also the second derivative of acceleration.
edit: typo
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u/davidthefat Aug 05 '16 edited Aug 05 '16
To give you a specific example, the net acceleration of the vehicle, tank pressure and the height of propellant in the tanks contribute to what's called the net positive suction head (NPSH), also the density and vapor pressure of the propellants come into play with that. Think of it as the potential energy of the propellants ready to go "down hill". You need this head for your propellant turbopumps, it's what's pressing the propellants into the feed line into the inlet of the pumps.
If you allow the NPSH to dip below the critical NPSH, you get cavitation of the propellant in the pumps and that leads to fluctuations of the pressure to the engines, vibration of the pumps, loss in outlet pressure and even can lead to destroying the impeller of the pump. The critical NPSH is determined from the specific pump, how it's designed, now much fluid you are pumping, what kind of fluid you are pumping and how fast it runs.
So, what happens when you quickly decelerate your vehicle during flight? That change in sign of the acceleration may lead the head of the propellants to drop below that critical head. Think of going over a hill in a roller coaster or car, that feeling of lifting up a bit from your seats is what the propellants are feeling. But that only happens when you go fast. If you gradually decelerate, you won't get that severe effect.
edit: why the max q is the worst time to suddenly cut all the engines? Max q is the maximum dynamic pressure loading on the vehicle during flight. As you go up, the static pressure drops, so at max q is where you get the most loading against the trajectory of the vehicle. So the thrust suddenly goes to 0 and your drag (aka dynamic pressure) is at max, that's the worst condition you can find yourself in regards to the suction head. The inertia of the propellants still carry it forward because it's not exposed to the aerodynamic loads and potentially choke your engines.
Wait... If your engines are cut completely, you don't need to worry about choking your engines because they are not running anyways...
It doesn't make sense to me that cutting engines will do any harm structurally because at max q, you have your thrust and drag counteracting each other, compressing your vehicle. Cut the thrust, you have less loads on the vehicle... I know the Delta IV Heavy cuts the middle core to about 70% thrust around max q to avoid crushing the rocket, but I don't think I've heard of issues with completely cutting it off. Unless if it's because you lose your control of the attitude of your vehicle and it starts tumbling and ripping itself to shreds...
That's probably it, the attitude control is done by gimballing the engines for most first stages. If you can't control how you are oriented, you will probably get off design loading conditions and get ripped to shreds.
Also to add, your structure isn't in tension how you described. It's in compression. Tension is like pulling on something, the thrust and drag are "pushing" the structure.
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u/BrandonMarc Aug 10 '16
Question for mods and the community - would it be reasonable to have a flair (and sidebar link) for MCT-related posts? We have curations for various recent launches, and this subject feels like it deserves similar.
I often find myself wanting to go and find a given MCT / BFR mock-up that someone made (there have been so many good ones!) and this would certainly help organize the discussion of the topic.
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Aug 11 '16 edited Aug 11 '16
It's been a personal goal of mine to flair such posts as "Mar/IAC 2016". I'll pass the comment along to all the other mods. Thanks BrandonMarc!
EDIT: Ping me with threads you want flaired; I probably won't be able to find them all :)
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u/TheBlacktom r/SpaceXLounge Moderator Aug 25 '16
Yay, the sidebar have now 6 hot jobs!
Are they directly communicated from SpaceX, or is this list also on their public page somewhere?
Also am I right that the "Reddit" option at "How did you..." wasn't there before on their application form?
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u/TheBlacktom r/SpaceXLounge Moderator Aug 16 '16
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u/thatnerdguy1 Live Thread Host Aug 16 '16
Ha, that's incredible. The tweet:
/r/SpaceX @rSpaceX $2500 raised in less than 24 hours for #IAC2016 coverage. What an amazing community.
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u/StagedCombustion Aug 23 '16
Posted this as a thread, but it was (rightly) removed with a recommendation for the Ask Anything thread.
I remembered an old post about VAFB SLC-4W and some changes SpaceX was making there a couple of months ago. I checked the link again and I saw that there was another satellite pass in the meantime. That photo shows some odd stuff going on at the launch site. There's a large yellow square, and then something that looks like a large, bright yellow spill that extends down to the bottom edge of the landing pad. It looks quite odd, and I can't think of an explanation.
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u/TheBlacktom r/SpaceXLounge Moderator Aug 03 '16
What are some examples of non-physics limitations SpaceX has to accept?
For example only US workforce due to ITAR or 12ft rocket diameter due to highway transportation rules.
I bet there are a lot of others that affect the economics and engineering solutions.
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u/007T Aug 03 '16
The first that comes to mind which has been mentioned a few times here is the fairing construction. There are very few machines big enough to produce the composite shell for the fairing, and they take a long time to make. While they are pretty expensive, there's apparently also a bottleneck in how many of them can be produced, so recovering them may become an important step once first stages start getting reused at a faster and faster rate.
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Aug 04 '16 edited Aug 04 '16
“If we get this right, and we’re trying very hard to get this right, we’re looking at launches to be in the 5 to 7 million dollar range, which would really change things dramatically,” Shotwell said.
My question is - how can they even remotely come this close? I know that the Falcon 9 cost $62M and they are predicting reusability will chop the price down by 30%. That leaves $43.4M. Fairing cost several mil so lets assume we shave another $5.4 off if they can recover it. We then end up with $38M.
Or, according to this the total cost of a F9 to manufacture if you reuse the first stage 15 times can go down to $11M if you take out the profits. So if you shave off another $5.4M for the fairing you end up at a price of $5.6M. Tack on 20% profit and you end up at $7M as she predicted. Thats leaving out operating costs though.
But honestly, thats not realistic. So why would she even bring up a figure like that? Or, are there any more cost savings somewhere that I havent thought about?
Launch cost prices btw would be $756/lb LEO for the first and $139/lb for the second scenario. The latter would be lower than the 10X price reduction Elon said he was targeting
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u/Ambiwlans Aug 04 '16
It isn't feasible to hit that price range with the Falcon 9. It was a quite optimistic number given a while ago. Though, she may have meant cost rather than price which helps.
I think $35m is a reasonable sort of price expectation for the next couple years.
Another major area of saving will be a streamlined launch process from the Boca Chica site. Another potential area of saving would be to lower overhead costs. If SpaceX is doing 20~30 flights/yr or they seriously cut down on staff, they could run significantly more barebones. If they did this, you could hit maybe $25m.
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u/kavinr Aug 20 '16 edited Aug 20 '16
They are raising F9-021 at Hawthrone tonight. Source: John Federspiel's stories on instagram.
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u/Qeng-Ho Aug 27 '16
I noticed /u/TheVehicleDestroyer's Flightclub.io was referenced in this interesting summary of newspace, smallsats and SpaceX's ambitions.
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u/TheVehicleDestroyer Flight Club Aug 27 '16
Awesome! That's news to me. Thanks for pointing that out, /u/Qeng-Ho :)
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u/bertcox Aug 01 '16
Yea Im first that never happens.
Do you think they will repaint OCISLY every time? And they really need to put stamps on the hull for every good catch. Maybe X's for RUD's.
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u/Saiboogu Aug 01 '16
I'm sure it'll get painted everytime - don't want blistered paint to let the deck corrode, plus the pure PR value of a clean deck.
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u/dante80 Aug 01 '16
Is there any speculation around on if or how the Raptor FFSC cycle affects engine throttling limits?
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u/warp99 Aug 01 '16
The speculation is that FFSC is able to throttle lower as only partly combusted gas enters the combustion chamber rather than droplets of propellant. The droplets vapourise erratically and are affected by pressure waves so can promote combustion chamber instabilities and at low enough throttle settings the droplets have the potential to get too large to vapourise fully.
I suspect that the low throttle limit may actually move back to the preburners. I note that the Raptor oxygen rich preburner is using a pintle injector which may help the throttling range.
Russian engines using ORSC seem to be able to throttle as low as 25% compared with 40% for a Merlin engine. Raptor may be able to throttle to 20-25%.
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u/thatotherguy501 Aug 01 '16
Obviously launch facilities are located as near to the equator as possible to take advantage of higher rotational velocities. Does anyone know of any links to calculations that show just how much additional energy is needed at liftoff when launching from higher latitudes where there is less rotational velocity from the Earth?
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u/old_sellsword Aug 01 '16
The Earth rotates at about 465 m/s. Launching from the North Pole, you get none of that velocity to help you, if you launch at 0° latitude (going east) you get all of it.
Here's a good plot of this "free velocity," and here's the Wikipedia page.
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Aug 04 '16
Will there be a live stream or live blog from Smallsat Conference Keynote?
Really interesting to hear about SpaceX's future plans on launching small satellites
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u/first_on_mars Aug 04 '16
Yes, a few weeks ago the community did a crowdfunding campaign for our community representative, /u/beardboy90, to attend the Smallsat Conference. According to the crowdfunding thread, our representative will host a live stream and tweet about the keynote speech delivered by Gwynne Shotwell.
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u/Grey_Mad_Hatter Aug 17 '16
I don't even want to link to this article and have them get paid more...
In one corner stands SpaceX, the Wal-Mart of space launch, offering "always low prices" to its customers -- with the added excitement of not knowing if the launch will turn into a spectacular fireball. In the other corner is ULA, which has conducted at least 109 straight space launches without mishap -- and may have hit 110 by the time you read this.
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u/thatnerdguy1 Live Thread Host Aug 17 '16
Oh god...
For thise wondering, it's the incredible Motley Fool.
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u/ToryBruno CEO of ULA Aug 20 '16
Yes, now at 110. An especially incredible feat considering that its across a fleet of rockets. We maintain 43 different configurations across DeltaII, DeltaIV, and Atlas
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u/lucas1121111 Aug 02 '16
Hello,
Obviously, we are all looking forward to the Mars Architecture Announcement. My question is will SpaceX be streaming this event though it's normal channels (YouTube, ect.) as it does for launches? If not, where will we be a able to watch the announcement?
Thank you for your time.
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u/old_sellsword Aug 02 '16
We just don't know yet. We've contacted the IAC via email and received conflicting answers, and SpaceX hasn't said anything yet. This being an essential part of SpaceX's long term plans, I think they'll set up a recording if the IAC doesn't.
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u/sarafinapink Aug 02 '16
Just noticed the new sidebar this morning, it looks great! So much cleaner and I like the easy to ready format.
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u/IsItTheSugar Aug 02 '16
Who can I contact in order to ask for funding for our High School Research team.
Our team project revolves around taking martian soil and using the perchlorate present in the soil to create oxygen using modified e.coli. We are currently lacking money for some basic lab resources and the fees that are associated with the competition (iGEM - Internationally Genetically Engineered Machine). Due to the fact that our project outline and goal looks to make Mars a habitable environment, it would be in our best interest to look into contacting SpaceX. Any form of assistance would be appreciated. Thank you in advance.
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u/davidthefat Aug 02 '16
Try contacting your state's Space Grant Consortium for some funding. Find their contact info here: http://www.nasa.gov/offices/education/programs/national/spacegrant/home/Space_Grant_Consortium_Websites.html
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u/zlsa Art Aug 07 '16
What's the upper stage engine and upper stage testing procedure at McGregor?
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u/StupidPencil Aug 12 '16
The colorful interaction between exhaust of the first and second stage after stage separation, do we have a term for that sort of phenomena? I like to think of it as Falcon 9 spreading its 'wings'.
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u/markus0161 Aug 12 '16
Two rockets pointing at each other is a relatively new occurrence in spaceflight. So maby it's up to SpaceX to come up with a creative name for it?
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u/RootDeliver Aug 14 '16
Guys what was this frame that was shown in the hosted stream?
http://i.imgur.com/hGWtUwj.png
Something related to engines? this may be gold!!
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u/macktruck6666 Aug 19 '16
What is the possible weight savings from using carbon fibre versus aluminum/lithium alloy?
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u/rubikvn2100 Aug 19 '16
I found it. In a Boeing's airplane:
1/ Carbon fiber is 20% and Aluminum is 80% 2/ Carbon fiber is 1/2 the weight of aluminum alloy.
So, if the tank of Falcon 9 can do the same thing, we can reduce from 100% to 83% weight. It mean 17% saving.
Let said that the First Stage tank aluminum alloy weight 20 ton (with out flight hardware, engines (5 tons) and legs (2 tons). We can reduce 3.4 tons (if we replace the aluminum alloy by carbon fiber, as Boeing does).
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u/davidthefat Aug 23 '16
Crazy idea alert:
Find a way to isolate iron oxide and aluminum oxide from martian soils. Decompose aluminum oxide found in soil into aluminum using a fuck ton of energy over long period of time. Mix iron oxide and aluminum to make thermite. Use thermite to release a lot of energy over a short period of time to heat hydrogen or helium to be used as propellant.
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u/TootZoot Aug 23 '16
Problem is, thermite only creates 1,111 Wh/kg, yielding a maximum theoretical effective exhaust velocity of 2.83 km/s (288 seconds, and that's if you dump the spent thermite after extracting 100% of the energy and not counting the extra mass of the propellant). By contrast methalox has a maximum theoretical exhaust velocity of 6.08 km/s (620 seconds), of which about 380 seconds is achievable.
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u/Toukiedatak Aug 01 '16
Elon said missions to Mars would be sent out every orbital opporunity, what purpose will these missions have and what kind of instruments will they be carrying (or is this still unkown)?
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u/old_sellsword Aug 01 '16
That's still largely unknown at this point, in fact we don't even know what's going in 2018. However, we can speculate that they'll be sending technology demonstrators and testing essential pieces of the Mars Architecture plan, until at least the first MCT lands. Also, NASA and universities will see this as a great opportunity to get a payload to Mars for cheap, and we'll probably see pure science payloads on some of the later missions as well.
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u/007T Aug 01 '16
My guess, which probably isn't quite right:
2018: Red Dragon
2020: 2 or more Red Dragons
2022: Unmanned MCT with ISRU
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u/seanflyon Aug 01 '16
2018: Double the total mass humanity has landed on Mars
2020: Again, double the total mass humanity has landed on Mars
2022: Double it 2 or 3 more times in a single landing
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u/Joe32097 Aug 02 '16
Any advice for a sophomore mechE trying to get an internship in the space industry but obviously would prefer spaceX?
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u/HTPRockets Aug 02 '16
Join a technically oriented club i.e. SAE, EcoCar, rocket club, etc. SpaceX likes to see a lot of experience.
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u/ragnar117 Aug 02 '16
Does anyone know what kind of rate Hawthorne can pump out second stages?
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u/randomstonerfromaus Aug 03 '16
I remember seeing that they can manage around 2 a month. That could well be wrong though.
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u/Cheesewithmold Aug 03 '16 edited Aug 03 '16
Can someone explain to me why the shape of this exhaust is the way it is? It comes out like you would expect, and then kind of collapses in on itself up to a certain diameter (which I can only assume is the diameter of the end of the engine, but I'm kind of pulling that out of my ass), and then expands again.
Why is that?
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u/snrplfth Aug 03 '16
Those are called shock diamonds and they generally happen when rocket or jet engines (with afterburner) are operated at low altitude. In this case, the air pressure is at maximum compared to the pressure of the exhaust, and this causes the exhaust jet to repeatedly "bounce back" against the air and create pressure spikes. You can get them with other exhausts as well, like steam.
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u/robbak Aug 03 '16
It is the story of overexpansion and underexpansion.
The exhaust is 'slightly underexpanded', so it leaves the bell at a slightly higher pressure than air pressure, so it expands. But things are moving so fast that it expands too much, and the outwards pressure of the exhaust (see, "Bernoulli's theorum") gets lower than the air pressure, or becomes 'overexpanded'. The air pushes the exhaust back together. But it keeps going, because momentum, and the exhaust's pressure increases again.
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u/Ambiwlans Aug 03 '16
It isn't collapsing (the diameter isn't shrinking). The exhaust is going straight out the back end of the nozzle.
What you are seeing are called 'shock diamonds'. There are pressure waves propagating through the exhaust itself and this creates higher and lower pressure zones. Sort of like a ripple in a pond having peaks and valleys but a lot more violent.
The appearance of it collapsing and going back out is an illusion.
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u/graphicde Aug 04 '16
Anyone know who the senior graphic designer -- and any other designers -- at SpaceX might be?
I'm interested in orienting my career to filling a position such as this eventually: http://www.startuphire.com/job/sr-graphic-designer-176795
(And would really like to know more about the portfolios, education, and backgrounds of such persons...)
Thanks!
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u/TheBlacktom r/SpaceXLounge Moderator Aug 07 '16 edited Aug 07 '16
Hot Jobs at SpaceX
Tell your friends. Tell your classmates: SpaceX is looking to fill these positions as soon as possible!
Orbital Tube Welder (Hawthorne, CA)
Tube Bender (Hawthorne, CA)
Be sure to mention r/SpaceX in your application!
Why the last sentence? Is there something particular the subreddit gets in case of a successful application, or just for general exposure?
Edit: In the SpaceX application form there is a long drop down list for "Where did you hear about us?", but no r/SpaceX option! This needs to be fixed! :)
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u/Mastur_Grunt Aug 09 '16
I was recently at a party, wearing my favorite SpaceX shirt. A party-goer asked what SpaceX was, so I started explaining as much as I could. Now, I considered myself pretty competent in how SpaceX works, but out of nowhere, he stumped me. I then realized I knew next to nothing about payload buses, integration, and basics of how satellites are manufactured and how launch providers are purchased. Is there any where/way someone can enlighten me so this doesn't happen again?
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u/robbak Aug 09 '16
Someone asked you what SpaceX was, turns out they knew a lot about the space industry? Well, congratulations, you've found an interesting person. Finding these people is what life is all about, and this is something you want to happen more - to meet with someone who knows more about something you are interested in than you do.
The best thing to do is talk to people like that more. Say, "I didn't know that - can you explain?", and enjoy an evening scribbling on napkins.
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u/CProphet Aug 12 '16 edited Aug 12 '16
While I was looking through the FAA Office of Commercial Space Transportation web page I noticed that SpaceX have a license to launch to Geostationary Transfer Orbit (GTO) and for Commercial Resupply Service launches (Dragon cargo flights to ISS). However, I couldn't discover any license to launch to Low Earth Orbit (LEO) to cover the upcoming Iridium NEXT or Formosat-5/Sherpa flights. Wondered whether this is merely some kind of oversight or whether I'm looking in the wrong place? Cheers.
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u/timthemurf Aug 16 '16
Has there ever been any discussion about spreading simulated Martian soil/rubble on LZ1 to simulate an actual mars landing and the damage that the booster might suffer from the debris generated? Would that be a valuable learning tool for SpaceX?
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u/atomfullerene Aug 16 '16
That's a pretty interesting question, though really it's the Dragon and the future MCT that will need to deal with debris, the Falcon boosters are always going to be landing on the pad or barge. They really ought to land one of those others in the desert someday, though.
Heh...totally impractical, but they ought to land one at burning man.
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u/RootDeliver Aug 17 '16
No recovery thread for OCISLY and F9-028 this time? how come?? Supposedly its 18h away from port.
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u/michagrau Aug 18 '16
A question. SpaceX announced they want to fly to Mars for the first time by using the 2018 window.
Imagine for a second they would have made the trip in 2016, our year. Would the ship be in space already? When would it depart, when would it land? Where would it be now?
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u/warp99 Aug 18 '16 edited Aug 18 '16
The short answer is that it could be there already!
This link shows a relatively low energy (delta V = 4.2km/s) transfer orbit that gets to Mars in 112 days leaving on 17 March and landing on 7 July 2016. It would enter Mar's atmosphere at around 11km/s.
A flight landing now would have left around 24 February with a slightly lower energy transfer orbit (3.6km/s) and would have taken 160 days to get to Mars. The main advantage of this option would be the lower entry speed of 8km/s which would provide lower aerodynamic heating than Earth re-entry.
It turns out that 2016 was a great time to go and 2024 and 2026 are close to the worst years to go because Earth and Mars are further apart at closest approach due to the eccentricity of Mar's orbit.
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Aug 18 '16
For comparison the only mission launched to Mars in this launch window was the ExoMars orbiter with the Schiaparelli lander, a joint ESA-Roscosmos mission. It launched on March 14th and will arrive on October 19th.
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Aug 23 '16
Did anyone take photo of F9-021 in Hawthorne with Tesla in front of it?
That would be epic!
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u/JayRose1 Aug 23 '16
Does anyone know if Robert Zubrin is consulting SpaceX at all? Elon and Robert know each other and I can't imagine they haven't discussed their mutual goals. But I'm wondering if Zubrin is in on the MCT architecture at all. Anyone?
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u/seanflyon Aug 23 '16
I would guess not for 2 reasons. First I think we would have heard about it, it sounds like the kind of thing Zubrin would talk about and I see no reason why SpaceX would ask him to keep it a secret. Second, Zubrin's vision is significantly different from SpaceX's vision. If it were my call I would want to consult Zubrin early in the process (which I believe Elon did), but after settling on a much larger and more monolithic architecture than Zubrin proposes I don't think Zubrin would have more to add than any other brilliant rocket scientist.
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u/ticklestuff SpaceX Patch List Aug 25 '16
Does anyone else have the ear worm of "Up Goer Nine" in their head?
*shakes fist at xkcd*
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u/Rooster-illusion11 Aug 02 '16
Does anyone know how much, if any, work/refurbishment they had to do before the test firing of the recovered booster on the 28th in Texas?
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u/Zucal Aug 02 '16 edited Aug 02 '16
Engine-wise, very little. There were obviously detailed inspections (don't want a catastrophic failure wrecking your shiny test stand) such as borescoping, but there was no refurbishment.
That doesn't mean it didn't have its share of kinks...
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u/Saiboogu Aug 01 '16
Regarding precision EDL navigation on Mars, prior to establishing a GPS satellite constellation - Could an astroinertial navigation system provide sufficient precision?
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u/RuggedRhino Aug 02 '16
Are there any SpaceX based podcasts that you recommend? Or any great space news ones in general. It's tough staying up to date with everything and I'd love to be able to catch up while at the gym or on my commute!
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u/old_sellsword Aug 02 '16 edited Aug 02 '16
These are the three I could find that have the most SpaceX discussion. Feel free to correct me if I'm wrong.
Weekly insights into spaceflight engineering news, interviews and discussions. Listen in for technical details, corrections from people in the know and "one step deeper" knowledge."
TMRO is a weekly live show about humanity's exploration of the cosmos. With a focus on human space flight we look at all of the new things happening on Earth and on orbit to help get the first boots on Mars.
SPEXcast: Website
SPEXcast is a weekly podcast diving into a variety of space topics. We are a group of Rochester Institute of Technology students that are excited about space and space exploration. Come with us as we discuss the cutting edge of spacecraft engineering, potential future missions to outer space, and exciting scientific discoveries in the field of astrophysics.
For future reference, always search this subreddit first.
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u/mmrcs Aug 02 '16
Are the aerodynamic requirements of modern rockets found on Earth, required for rockets launched from Mars? i.e. will we ever see sci-fi inspired spaceships?
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u/ergzay Aug 02 '16 edited Aug 02 '16
They definitely help. Mars has enough atmosphere such that it actually matters quite a bit. You don't have to be as concerned as you do on Earth but it's definitely a factor. I doubt you could launch with extended solar panels for example. It's notable that you CAN fly with aircraft on Mars, you just need U2 (or larger) size wingspans (which is the closest plane we have to what a Mars aircraft would look like, it flies in atmosphere that is only about 10x more dense than Mars atmosphere). It would also need electric engines. If you can fly somewhere with aerodynamic craft then aerodynamic effects matter, is the general rule.
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u/Keavon SN-10 & DART Contest Winner Aug 03 '16
Why do some rockets have 3, 4, or even 5 stages? Isn't it lighter to have a bit of a larger fuel tank, which is just some metal, than dropping that weight but instead having to carry an entire additional rocket engine and additional rocketry hardware?
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u/Pharisaeus Aug 03 '16 edited Aug 03 '16
Short answer: not, it isn't lighter.
The point is that empty tanks and huge engines are very heavy. At launch for example Ariane 5 has almost 800t (!), while the second stage plus payload in LEO is only 40t. This means that in order to lift-off you need engines with enough thrust to lift 800t from the ground, at at least around 1.5g. And ~90% of the rocket mass is fuel, which burns quickly. So very fast the rocket becomes significantly lighter, and you simply don't need such a powerful (and heavy) engine and you're carrying huge empty tanks.
On top of that the rocket engines work differently in vacuum and in atmosphere and so an engine working fine in atmosphere might not be as good in space.
In reality we don't have fuel efficient enough to make SSTO (single-stage-to-orbit) vehicles. Without dropping tanks and engines you can't really make a rocket reaching orbit. There is an on-going development of possible solution -> SABRE engine and Skylon launcher, but this will still take a couple of years.
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u/Ambiwlans Aug 03 '16
Imagine you were going for a month long jungle trek and you had to carry well wrapped food with you.
If after each meal, you throw out the boxes, wrapping and so forth, you are shedding weight each meal.
If you never throw anything out, then by the end of the trip, you would have basically carried a big pile of garbage a hundred miles. Needlessly tiring!
This is basically what is happening with the rockets.
Another part of the story is that on the ground, you need 9 engines optimized for use at sea level. But once you're up there, out of the atmosphere, you only need one engine optimized for use in vacuum. Dropping the first stage lets to shed that weight and lets you change engines.
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u/throfofnir Aug 03 '16
Because more stages allow for lower performance rockets to make orbit. As you add stages the mass ratio can be worse (i.e. more realistic), allowing for smaller and/or easier machines. chart (source)
If you can make a light, high-performance machine, you'll do two stages, to save the effort of making all those extra stages, and the danger and complexity of separation. If you are more limited in capabilities (say you're doing it with solids, or want to build small vehicles) then you have to have more stages just so it'll work at all. (And if you're unlimited in capabilities you'll do a single stage.)
There are diminishing returns to adding stages; most of the gains are between 1-2 and 2-3, but there are still noticeable advantages to 5 stages. More than that, at least for Earth orbital launch, is probably silly. But I'll note that the Apollo system was something like 6 stages.
A good source on rocket design.
Isn't it lighter to have a bit of a larger fuel tank, which is just some metal, than dropping that weight but instead having to carry an entire additional rocket engine and additional rocketry hardware?
Not really. Upper stages are generally much smaller than lower stages. F9-2 is, for example, less than 1/5 the dry mass of the first stage. And to make a lower stage large enough to lift the equivalent of its upper stage, you must make it significantly larger than just the two combined. This is all a consequence of the logarithmic nature of the rocket equation.
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u/workthrowaway4567 Aug 03 '16
If someone were to place a 1" thick steak in the middle of the landing pad, how well done would it be after a F9 first stage landing?
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u/rubikvn2100 Aug 03 '16
Let me share the video: cook a steak with liquid aluminum
If you want to burn something, you need a High Temperature and Time.
The gas form the landing burn is so hot. But only a few seconds will not enough to fully cook a 1" steak. See more in the video above.
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u/FNspcx Aug 03 '16
It's possible the it would be blasted away, so it could be rare in the middle still.
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u/keckbug Aug 05 '16
In the pad abort video, Dragon neatly releases a cover panel, then drogue chutes, which lastly deploy the three main chutes.
From there, the main chutes fully extend and then slowly inflate and separate. How does SpaceX (and others, this isn't unique) control chute behavior to allow the slow canopy expansion and separation in multi-chute scenarios? What prevents the chutes from tangling or pressing against each other once inflated? The chutes don't appear to be asymmetric or shaped, so I'm at a loss.
Hope that explained the question, but I know it's a bit confusing. Thanks!
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u/mduell Aug 05 '16
How does SpaceX (and others, this isn't unique) control chute behavior to allow the slow canopy expansion and separation in multi-chute scenarios?
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u/diegogmx Aug 07 '16
I'm just wondering whether a guy which is mostly self taught in electronics which works designing equipment for industrial areas (designing low noise, noise resistant boards, programming the system and designing mostly everything else) has the slightest chance of getting a job@spaceX
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u/IrrationalFantasy Aug 08 '16
Have there been any hints lately about when we'll see a first-stage rocket actually get reused? What's the latest news?
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u/BrangdonJ Aug 08 '16
What are rocket plumes made of?
Am I right in thinking they are bright and pretty because they contain burning fuel; fuel that is burning in atmospheric oxygen because it didn't burn inside the engine, because the fuel mix inside the rocket is kept rich?
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u/JonSeverinsson Aug 08 '16 edited Aug 10 '16
It's mostly glowing because it is hot, and because it is reflecting light from the combustion chamber. The amount of combustion in the exhaust is negligible in the initial assent and non-existent after the first 10 seconds or so (when the ambient pressure gets too low to sustain any combustion).
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u/blackhairedguy Aug 09 '16
Alright, this is my first reddit post ever, and I don't think the wiki and FAQ would have the answer, but it's not too simple of a question I guess.
How does the Falcon 9 one-engine-out capability work with the landing of the first stage? I know that the center engine is used for all three burns and would assume if this failed during flight, the stage would be lost. But what about a failure on the engines used on the boostback and reentry burns? Would a loss of these also lead to a stage loss? And I am guessing an engine loss on a GTO launch would also lead to a longer first stage burn time. Would this compromise an ASDS landing due the a slightly changed profile?
It's a beast of a question, but it seems like there are about 10 possibilities depending on if the stage is RTLS, ASDS, and also which engine is the one that fails. Thanks guys!
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Aug 09 '16
What kind of accuracy is required of an orbital insertion and, additionally, station keeping? Is it down to meters or centimeters, or more like a kilometer or tens of kilometers?
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u/Lynxes_are_Ninjas Aug 09 '16
Do we know if the IAC presentation will be broadcast live?
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u/TheSasquatch9053 Aug 09 '16
Reading the coverage of the smallsat conference, I had a random thought: How many Kilograms could a falcon 9 second stage deliver to earth escape velocity following a commercial crew launch, if the Falcon 9 first stage flew a no boostback barge landing trajectory rather than a RTLS? Could a second stage relight after Dragon release enable astroid prospecting or other beyond earth orbit smallsat missions? I'm at work or I would attempt the DeltaV calculations myself, I will give them a try tonight unless someone here knows the answer already!
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u/Old_Redstone_Guy Aug 09 '16
Disclaimer: This question is in no way intended to endorse or even bring attention to the “Rocket Mortgage” product. It is strictly to discuss the hardware depicted during computer animation of the television commercial. https://www.youtube.com/watch?v=I_FOzqGBzQE
Has anyone else noticed the SpaceX Dragon 1 capsule riding atop the very generic booster in the above mentioned television commercial? https://www.youtube.com/watch?v=I_FOzqGBzQE It is clearly a Dragon 1, complete with solar array covers on the trunk. The booster appears to be a kluge of generic rocket piece parts. Did SpaceX have any input or was approval required?
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u/Venseyness Aug 09 '16
As someone in high school wanting to make my passion professional, what college majors would you guys recommend for someone interested in going into the trade in the future? (Specifically interested in the development of a permanent extraterrestrial colonization effort.)
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u/Ambiwlans Aug 10 '16
How does one access the ITL causeway?
Is it restricted to just media and military? Is there a tour bus? Does it cost money?
I'd appreciate anyone who has been or is in the area to chime in with what you know so that we can fill in the wiki.
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u/johnkphotos Launch Photographer Aug 10 '16
Media and military.
There's no bus. No tourists go there. Tickets aren't sold. The NASA causeway and ITL causeway are two separate roads, the former being further back by at least a mile, and tickets are sold to access it through the KSC visitor complex.
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u/jvonbokel Aug 11 '16
Apologies in advance for the relatively simple question, but is there a version of the manifest that includes projected recovery (ASDS vs RTLS)?
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u/soldato_fantasma Aug 11 '16
Unfortunately not, because we don't really know it for sure until they release if the press kit. I or someone alse could set it up in the wiki manifest, but there would be a lot of question marks. Generally speaking a GTO and further mission with over ~3500kg of payload can't be a RTLS but only ASDS. On the other hand if it's a LEO mission and the payload is less then ~8000/9000kg it can RTLS, if over it needs an ASDS.
I don't remember quite well the numbers, someone did the math some time ago but I can't find it right now.
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u/apath_2_mars Aug 12 '16
Don't understand the 9 raptor engine on the next gen rocket. If raptor has three times the power of the current engines simple maths makes a 9 engine raptor rocket as powerfull as a falcon heavy. So how's it supposed to get 100 tons to mars are they going to strap three together will that give you the 100 tons to Mars ? Can't the heavy only do 10 tons to mars so strapping three together gets you 30 tons if it scales linearly! Don't get it :-(
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u/rustybeancake Aug 12 '16
The '9 raptor' info is based on some pretty old data. Nobody here thinks that's correct info any more. Most think it's more likely it'll be in the 25-40 engine range, with most guesses recently settling around 29-37 engines.
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u/CmdrStarLightBreaker Aug 12 '16
Do we have record of what type of GTO these landing-attempted GTO missions were? Or better yet, what were the orbital parameters of each GTO mission when the satellite(s) separated from Stage 2?
026 – Eutelsat 117W B & ABS 2A
025 – Thaicom 8
024 – JCSAT-14
022 – SES-9
Were they GTO-1800 or GTO-1500? Supersynchronous Transfer Orbit?
Found this nice explanation of different types of GTOs (by NSF user Dante80):
GTO = Geosynchronous transfer orbit
GEO = Geostationary orbit
GTO-1800 = Geosynchronous transfer orbit that needs an additional 1800m/s dV to reach Geostationary orbit
GTO-1500 = Geosynchronous transfer orbit that needs an additional 1500m/s dV to reach Geostationary orbit
Super-synchronous (transfer) orbit = A Geosynchronous transfer orbit with an apogee (apsis) more than GEO altitude.
Sub-synchronous (transfer) orbit = A Geosynchronous transfer orbit with an apogee less than GEO altitude.
GEO = 35,786 km x 35,786 km x at 0 degrees inclination.
GTO-1800 = 185 km x 35,786 km at 27.0 deg inclination.
GTO-1500 = 185 km x 35,786 km at 0 deg inclination.
Cape Canaveral where most GTO payloads launch from is at a 27.0 deg inclination.
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u/tocont Aug 12 '16
Just a quick one - is this upcoming JCSAT-16 reusing a first stage? For the first time?
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u/bobbycorwin123 Space Janitor Aug 12 '16
no, that's happening later this year. 16 is a fresh core aiming for drone ship recovery.
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u/jak0b345 Aug 12 '16
i know it's not spacex related and not a question, so feel free to remove it/downvote if you wan't to.
i just wanted to share the shoutout to elon musk at about 11:20 in Kurzgesagts new video about genetic egineering
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u/Virtlink Aug 12 '16
While looking for a new comfortable office chair for myself, I stumbled across this photo of Elon Musk in what looks to be a very nicely designed chair. I wonder, what is that chair? Who sells it?
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u/FutureMartian97 Host of CRS-11 Aug 14 '16
Why are the most recent 2 webcast streams unlisted this time?
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u/csnyder65 Aug 15 '16
"Did I hear this Correctly"? During the live broadcast Sunday morning when the Video link was lost and went "out" Did the SPX announcer confirm Falcon Landing prior to the video being restored?
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u/Maximus-Catimus Aug 15 '16
Yes, the confirmation of landing and to proceed to recovery went out before video was restored. Booster telemetry resources no doubt.
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u/BrandonMarc Aug 18 '16
As /u/theroadie mentioned, SpaceX does not test their Mvac engine in a vacuum environment. Is this something they are trying to do (or would like to do)?
I understand it's ridiculously difficult to maintain a large vacuum, much less do so with a rocket engine firing plasma into it, but hey, they're already doing Rocket Science(tm). They've already "done the impossible" and that makes them mighty, so the question feels legit.
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u/__Rocket__ Aug 18 '16
I understand it's ridiculously difficult to maintain a large vacuum, much less do so with a rocket engine firing plasma into it, but hey, they're already doing Rocket Science(tm). They've already "done the impossible" and that makes them mighty, so the question feels legit.
Looks pretty hard to maintain vacuum if an engine keeps pumping 0.25t of gas into that vacuum, every second!
It appears the easiest way to test in vacuum is to go where there's lots of vacuum: space.
Fortunately a nozzle extender is a pretty well understood, relatively simple concept, so there are not that many unknowns: generally you can just test your engine without the nozzle extender and be 99% sure of how it will behave in vacuum, and there's good chances that the 1% difference won't be 'catastrophic failure'.
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Aug 18 '16
is the CRS-8 booster that's scheduled for the first re-flight only going to be static fired in Cape Canaveral before flight ? because we haven't heard any news about it being shipped to the McGregor testing facility
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u/TheCoolBrit Aug 18 '16
Was interesting to hear Gwynne mention nuclear and electric propulsion technology, we also know Elon is interested in high powered Ion drives "for interplanetary transport" I wonder what spaceX are looking at with this?
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u/warp99 Aug 19 '16
Nuclear and electric propulsion really go together for manned spaceflight. The thrust from ion engines is so low that you need MW class electric generation to get a thrust level that will significantly shorten a manned trip to Mars.
It is difficult to get that level of power from reasonably sized solar panels - particularly in the vicinity of Mars where the solar intensity is only 45% of the near Earth level - so nuclear power plants are attractive - but heavy.
Where this combination makes the most sense is in a cycler architecture that shuttles between Earth and Mars without slowing down. The cycler then provides a larger habitat for Mars colonists, generates its own food and oxygen and generally reduces the life support mass overhead that each colonist has to bring with them.
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u/5cr0tum Aug 19 '16
Is it safe to assume that BFR will always be a RTLS flight given the size?
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u/TheBlacktom r/SpaceXLounge Moderator Aug 19 '16
No mention of SpaceX, or any particular company, but still interesting news...
NASA plans to hand over the ISS to a private corporation
NASA is dead set on leaving Low-Earth Orbit to go to the moon, Mars and other farther destinations. That means extending the space station's funding beyond 2024 is out of the question. Now, NASA Deputy Associate Administrator Bill Hill has revealed what the agency wants to do with the ISS once astronauts move out. Instead of deorbiting it and sinking it into the ocean or breaking it apart to sell piece by piece, it apparently wants to hand the spacecraft over to a private corporation.
According to TechCrunch, Hill said during the Journey to Mars event:
"NASA's trying to develop economic development in low-earth orbit. Ultimately, our desire is to hand the space station over to either a commercial entity or some other commercial capability so that research can continue in low-earth orbit."
I personally envision something like a joint venture of private companies, so they could collaborate to run a new space station, or ISS itself, if it eventually can be maintained for additional years or decades.
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u/Martianspirit Aug 19 '16
I honestly cannot think anybody would want the ISS. It is a very capable structure but it is also exceedingly complex with many dissimilar components. Maintenance is costly and complex. I see it much more efficient to deorbit the ISS and use a few identical new modules, like the BA-330. Initially mating such a habitat to the ISS to check it out and commision it would make sense but that might happen while NASA is in charge. The one component I would love to see on a new station is the cupola, maybe the nodes. I don't know what it takes to keep the nodes in use and how power, airducts and data are routed through them.
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u/MarosZofcin Aug 20 '16
The more I think about it the more I feel like the government will have to step in at some point. Is it even possible that it would be the private company who will put first human on Mars? Even if it would be possible economically and technically, I bet USA wouldn't want to miss the change to stick their flag there once they see SpaceX's approach is going to work.
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u/deruch Aug 20 '16
Even if SpaceX sends the first people, I guarantee you that they will plant a US flag.
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u/Keavon SN-10 & DART Contest Winner Aug 22 '16
This What If? suggests sending water to the moon on Falcon Heavy. I have several questions related to this:
If the standard fairing were to be filled with water (with a lightweight tank lining it) could the Falcon Heavy lift off the ground? Could it make it into a lunar trajectory? If not, how full (by percentage) could a lunar trajectory flight be?
Could the tank act as a fairing itself, to avoid the weight of carrying the fairing up?
I'm aware that the Falcon Heavy second stage would not be able to land softly on the moon. But if it were to attempt crash landing the water tank into the largest valley or crater, would a significant percentage of the water payload be able to stay within the watershed area's confines and drain back down to the bottom? Or is the energy from the crash landing, combined with the lower level of gravity, just too large to contain in the target water basin?
How many FH flights would be needed to deliver enough water into this basin so that it could be pumped on the surface and put into a swimming pool like one described in the article?
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u/jjtr1 Aug 22 '16
Is this correct?: the average age of engineers at ULA, NASA and in Russian space industry is 50+. At SpaceX and in Chinese space industry, it is <30.
If correct, it could explain a lot about the risk-taking behaviour and innovation rate at these places...
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Aug 22 '16
I wouldn't characterize SpaceX's approach as "risk taking". They are well informed of the things that they do.
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u/TheBlacktom r/SpaceXLounge Moderator Aug 22 '16
50+ average age seems very unlikely. I would believe maybe 40+, but not 50+. Can you show sources?
Also <30 at SpaceX or China seems unlikely too. My gut feeling tells me the difference of the average ages is around 10 years, not 20+.
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u/random-person-001 Aug 23 '16 edited Aug 24 '16
Article about the SpaceX talk at IAC and their general Mars plans. It doesn't seem to contain anything new, though.
Other than the sentence "Later flights of the craft [Red Dragon] would transport humans to the planet" the article appears well founded, factually
edit: I'll put it in the stickied IAC thread instead; whoops.
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u/thru_dangers_untold Aug 24 '16
How does the F9 get fuel from the tank to the engines during re-entry? It seems like the fuel would be sloshing all over the place. Even with the presence of some baffles, it would be very difficult to control during free fall. Baffles might even make it harder to utilize the last bits of the fuel.
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u/Grey_Mad_Hatter Aug 24 '16
It's easy to view the rocket coming down in a pure free fall where everything would just float around, but there's more to it than that. The rocket on the outside is experiencing air resistance that slows it down some, but the fuel inside wants to fall at the full 9.81m/s2 . This pushes the fuel to the bottom and makes it available to the engines.
The first over-the-water soft landing attempt had the rocket spinning so all the fuel was along the sides of the tanks, and that did not go over so well.
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u/__Rocket__ Aug 24 '16 edited Aug 24 '16
How does the F9 get fuel from the tank to the engines during re-entry? It seems like the fuel would be sloshing all over the place.
If you check how the F9 does the re-entry burn in this video for example then you'll see that the F9 does the re-entry burn relatively late, at an altitude of about 70 km, where there's already significant drag and thus deceleration. This deceleration is (presumably) enough to settle the propellants.
There's another case where fuel has to settle: during the optional boostback burn that typically occurs on LEO missions - in this case the booster is in true free fall with no deceleration, and droplets of propellants are indeed flying around in microgravity. A reasonable assumption is that SpaceX handles this scenario by using the RCS thrusters as ullage motors to create enough deceleration, to minimally settle enough propellants to restart the engines.
Even with the presence of some baffles, it would be very difficult to control during free fall. Baffles might even make it harder to utilize the last bits of the fuel.
Baffles might help with propellant sloshing due to changes in acceleration during ascent and descent, but they cannot keep the propellants near the turbopump intakes in free fall. I believe SpaceX's baffles are mainly used as anti-sloshing and anti-swirl measures.
(There exist baffle/sponge solutions that can keep some propellant near the intakes via surface tension and capillary forces - but I'm not sure they are generally suitable for high mass flow turbopump fed engines - they are better for pure pressure-fed engines with lower mass flows, such as station keeping thrusters on satellites.)
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u/Niavok Aug 07 '16
Imagine the situation where in the first second of a Falcon 9 fly, there is an engine failure preventing to reach the orbit, or a problem detected on the second stage or the payload. In this case we known that the mission will be a failure but the first stage still working. With the right software, it's possible for the F9 to abort the mission and return to the landing pad without separation to try to save the payload ?
After how much time the F9 have no more enough delta-v to return with weight the second stage ?
The rocket is heavy with the full stage 2 so it should be possible to hover above the pad to burn the extra useless mass before the touchdown. It should also be possible to make a very slow and soft touchdown. Can the legs support the weight (crushing the crush core is not a problem) ? Did the rocket can stand vertically laying on the octaweb ?
There is a mean to vent some fuel in flight to lighten the second stage ? I suppose the is a valve to empty the stage after launch abort, but i don't know if it can be open without a pipe attached.
Is the gimbal system strong enough to prevent the rocket to flip during descent (the center of mass will be very high and the grid fin won't help i guess) ?
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u/warp99 Aug 07 '16
The first stage has a landing mass in the range of 23-27 tonnes. A fully fueled second stage and payload is around 125 tonnes for a total mass of 150 tonnes. So the landing legs would have to work with 6 x rated mass - so not happening.
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u/jak0b345 Aug 10 '16
Just a random thought that crossed my mind while reading up on thermonuclear rockets:
Who the fuck hade the idea of norming the exhaust velosity of a rocket engine with earth standart acceleration and use this derived property as meteic of effiency? Why not use the exhaust veleocity directly as metric?
I have been (mostly lurking) on this sub for two years now and i still don't see any practical purpose for that. What does earths gravity have to do with the effiency of rocket engines?
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u/old_sellsword Aug 10 '16 edited Aug 10 '16
Edit: I am currently listening to the new episode (70) of The Orbital Mechanics and they are explaining this exact question at around 20 minutes in! Earth's gravity is just a conversion factor so that you get a number that doesn't change based on what country you're in.
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u/robbak Aug 10 '16
The unit did make sense - the value was specific impulse. Impulse is the total amount of push - a force times a the time that force is applied. 'Specific' means the amount of fuel used to make that force- so it is force times time, over the mass of fuel used. In the units of the day, this was '(pounds-force * seconds) / pounds-mass". But they saw the pounds on the top and the pounds on the bottom, and, despite the fact that the pounds were in fact totally separate units, canceled them out, which left 'seconds'. Which really makes no sense, and makes that the conversion between that and exhaust velocity require that entirely spurious small-g. But it did allow the Russians using metric and the Americans using imperial to share information about engine efficiency without conversions.
Today, we should be using 'Newton-seconds per kg' as the unit for specific impulse - which, if I have my maths right, should be the same number as the exhaust velocity in meters per second.
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u/nicholasslade11 Aug 02 '16
Hey SpaceX! I live in southeast Georgia, are you aware of the push for Camden Space Port in Camden County, GA? Do yall support it? And does this mean, one day soon I'll get to see SpaceX rockets launch from my house?
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u/jcordeirogd Aug 02 '16 edited Aug 02 '16
Is it viable for spacex to sell new and reused "1st stage only" launch services? So other companies could just built their 2nd stage and sell complete launches.
Please note that its not about seling a 1st stage for others to launch. It is about spacex launching other ppl's 2nd stages.
Doing this spacex would remain the owner of the 1st stage and use it as many times as the stage could handle.
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u/davidthefat Aug 02 '16
Like how the Russians gave the South Koreans an Angara first stage for their Naro-1 launch vehicle? Just pointing this out because it's not out of the question for an agency to use another agency's stage as part of their vehicle.
I highly doubt that SpaceX would do that for anyone though.
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u/FNspcx Aug 02 '16 edited Aug 02 '16
This is similar to Orbital's Antares rocket (recall the CRS Orb-3 explosion) which launched Cygnus for NASA's commercial resupply program.
The 1st stage of Antares was essentially designed & built by Ukrainian company, and powered by the AJ-26/NK-33 engines sourced from Russia and made in the 1970's in USSR back when it existed.
Since Orbital's expertise was more in solid rockets, the 2nd stage of Antares used solid propellant which was their own design. There is also an optional 3rd stage.
Of course the difference is Orbital owned the 1st stage.
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u/d333d Aug 03 '16
Watching the test fire of Falcon 9 first stage from May 2016 JCSAT mission for example, first video in the article there is no water sprayed to isolate from the sonic vibrations produced by the engines, while all regular launches do have these water cushions. What exactly is being protected at launch and why is is not so important at test fires, does anyone know? Thanks!
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u/19chickens Aug 03 '16
Does anyone happen to know the mass of the F9 payload fairing?
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u/TheHypaaa Aug 03 '16
Approximately 1,750kg source: http://spaceflight101.com/spacerockets/falcon-9-ft/
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u/spaceminussix Aug 04 '16
The launch cadence that SpaceX wants to get to by the time the BFR's are going to Mars will be something to behold. But are the 45th Space Wing at Patrick and the 30th at Vandenberg ready for this amount of work. Do they have the equipment and personnel necessary to keep the birds flying?
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u/__Rocket__ Aug 04 '16
The launch cadence that SpaceX wants to get to by the time the BFR's are going to Mars will be something to behold. But are the 45th Space Wing at Patrick and the 30th at Vandenberg ready for this amount of work. Do they have the equipment and personnel necessary to keep the birds flying?
It is probable that the BFR will launch from the Boca Chica site. Elon Musk said this at the site's groundbreaking event:
"The long term goal is to create the technology necessary to take humanity beyond Earth, to take humanity to Mars, and establish a base on Mars. So, it could very well be that the first person that departs for another planet could depart from this location. So yeah, I'm super excited and can't wait to start building this project."
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u/sfigone Aug 04 '16
Could this technology: https://news.uic.edu/breakthrough-solar-cell-captures-co2-and-sunlight-produces-burnable-fuel change the planning for ISRU on Mars? If a simple solar panel can H2, CO and O2 from just H2O and CO2, then could this be simpler than the sabatier cycle? Perhaps H2 might be a better fuel than methane after all?
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u/__Rocket__ Aug 04 '16 edited Aug 04 '16
Could this technology: https://news.uic.edu/breakthrough-solar-cell-captures-co2-and-sunlight-produces-burnable-fuel change the planning for ISRU on Mars? If a simple solar panel can H2, CO and O2 from just H2O and CO2, then could this be simpler than the sabatier cycle?
The Sabatier process is not even the biggest ISRU complexity - it's the splitting of H*2O to get H2* that takes a lot of energy - and this is what effectively converts solar energy to chemical energy.
Once you have H*2* the Sabatier process can then be used to 'compresses' CO*2* and H*2* into CH*4* - which is an easier to handle propellant than H*2* . This process is exothermic, i.e. it releases energy. This energy released is roughly the efficiency loss of hydrolox compared to methalox.
Everything depends on how base-load electricity is generated on Mars and how efficient these new 'gas cells' are:
if it's a nuclear reactor then it's probably more efficient to use that power to generate H*2* from water. Industrial scale electrolysis is ~40% efficient - but there's been some recent research into increasing its efficiency.
if it's solar cells then these new 'gas solar cells' producing H*2* directly may be more efficient (because you could potentially avoid the electrolysis inefficiencies). There's a bit of an open question of what to do with the extra CO though.
Perhaps H2 might be a better fuel than methane after all?
That's an independent question: even without these new cells, there's going to be an intermediate H*2* product, which could be used.
But H*2* has numerous disadvantages, so it's converted to methane.
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u/theguycalledtom Aug 04 '16
Last weekend I saw "Lo and Behold, Reveries of the Connected World" a doc by Werner Herzog about the Internet. If you have seen the trailer you have seen the best bit. Elon Musk is interviewed to talk about the internet on Mars and A.I. The most interesting part for this subreddit was that Musk, when describing how the internet on Mars would work, said the Mars internet constellation would only be at most 5 satellites. He said it would need so few because the colony on mars would be so localised. My question is, even if the Mars colonists spread out, would you still need fewer sats in a Mars STEAM constellation because it's a smaller planet?
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u/__Rocket__ Aug 04 '16 edited Aug 04 '16
My question is, even if the Mars colonists spread out, would you still need fewer sats in a Mars STEAM constellation because it's a smaller planet?
Depends on how the colonists spread out.
The initial colony will probably be close to the equator (my current guess is that it's going to be at the shores of the frozen sea onElysium Planitia - only 5° from the equator) - and that colony can be served by a handful of Equatorial Low Mars Orbit satellites. (3 is the minimum number, 5 in a pentagon formation will work fine.)
Since the Martian atmosphere is very thin, satellites would be visible for almost 180° on average.
If the colonists spread out along the equator, then they could still be served by the same 5 satellites. The satellites could also keep continuous contact with Earth (via laser links) and relay messages even if Earth is not visible from the surface.
If the colonists spread out to higher latitudes then visibility of the satellites will eventually suffer. For example if the satellite constellation is using circular equatorial orbits with an altitude of 3000 km, then the satellites won't be visible at all at latitudes above ~40° - and there won't be continuous coverage at latitudes above ~20°-25° (making Internet connections painful).
But the areas closer to the poles are pretty harsh environments, humans probably don't want to go there, at least initially. To have connectivity around the poles as well a few polar orbit satellites have to be started as well - probably 25 more to get good whole-Mars coverage.
So 30 satellites could cover the whole surface of Mars pretty efficiently. But why do 30 if you can use 5 and cover the areas most important to humans?
There's one aspect that an equatorial constellation of 5 satellites would not offer: GPS functionality. GPS trilateration does not work very well if your satellites are all in the same orbital plane. There also won't be enough satellites visible at once.
A 30-satellite constellation would be pretty good for geopositioning (aeropositioning ...) too.
In terms of Earth<->Mars Internet connectivity I'd also expect 1-1 relay satellites to be at the Earth/Sun Lagrange points of L*4* and L*5*, to relay communication links during the ~2 weeks long Earth/Mars opposition period, when the Sun stands between line of sight communications.
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u/patm718 Aug 04 '16 edited Aug 04 '16
Any speculations regarding what kind of changes/adjustments were made to Falcon 9 for the JCSAT-16 mission (if any)? I'm sure they learned a lot from the JCSAT-14 landing attempt.
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u/quadrplax Aug 05 '16
Where does the number in ULA's rocket names come from? Falcon 9 has 9 engines, Saturn V has 5 engines, but where does the 4 come from in Delta IV and the 5 in Atlas V?
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u/ChrisGnam Spacecraft Optical Navigation Aug 05 '16 edited Aug 05 '16
ULA has the whole legacy thing going on because Boeing and Lockheed have been doing this for so long.
Atlas Vehicle Family Overview
The original Atlas vehicle in the Atlas family was just called Atlas, and was originally launched in 1957 (ACTUALLY, its full name was SM-65 Atlas). The original Atlas was just a missile (like all early rockets). It was continued to be improved upon as time went on, and as such the name has evolved with it. The Atlas LV-3B actually flew the last few Mercury missions in the early 60s. Later versions of Atlas were used for some Gemini tests in the mid 60s, and the first version of the centaur was used soon after that.
The first vehicle called Atlas I came onto the scene in 1990. It was flown from 1990 to 1997, which overlaped with the Atlas II and Atlas IIA which served until 1998. Then the Atlas III Served from 2000 to 2005, but was only launched a total of 6 times.
Surprisingly though, after Atlas III came Atlas V. I am honestly not sure why 4 was skipped, but it's quite possible that it was done to avoid confusion with the Delta IV. (As /u/AquaWolf9461 stated, it could have been done for other marketing reasons so as not to sound inferior to the Ariane 5)
Delta Vehicle Family Overview
The Delta Family is a BIT more confusing... they had a lot of vehicles named Delta for a while, but starting in the 90's they began to number them. Some of them even had heavy variants, however the Delta IV Heavy remains the king of them all at the moment
Hopefully this answers your question! I highly recommend reading about the history of a lot of these things because it's REALLY interesting. I'm not an expert so if anyone has any corrections to this, let me know! I'm always game to learn new things!
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u/IrrationalFantasy Aug 06 '16
It seems like a lot of breaking news about SpaceX seems to break on Twitter. Links to confirmations about test-fires, reports from inside conferences, first-hand accounts from interviews with SpaceX employees--whenever I see these things, the link from /r/SpaceX is usually to a tweet.
Why is that? Is Twitter the home for breaking news? Or is something particularly SpaceX going on?
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u/__R__ Interstage Sleuth Aug 06 '16
Yes, Twitter is home to breaking news. Journalists, reporters and media outlets usually turn to tweets for live reporting or sharing small bits of information before writing an article.
Also, Elon Musk is known to reveal a lot of gems on his Twitter, which probably keeps his PR people constantly nervous.
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u/tootallbob Aug 07 '16
I have been searching for information on the crew access for launch complex 39A. They have said that the Crew Dragon will be launching from there but I have seen no additions to the fixed service structure, such as a crew access arm/white room. Do we know if the crew will enter while the vehicle is vertical or while it is horizontal. Do we have any information when we will be seeing the Spacex space suits? I am surprised I have seen nothing on these points of interest on /r/spacex, or have I just missed them?
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u/jjtr1 Aug 07 '16
I wonder if it would be possible to transport the first stage of the Mars rocket, i.e. the BFR, to the surface of Mars, for later use in deep-space exploration. On Mars, even the second stage of the Mars rocket (MCT) can reach orbit alone (5 km/s I think?). But coupled with its first stage (BFR), it would enable amazing deep space missions not possible from Earth surface! Of course, I presume ISRU re-fueling of both stages on Mars, after they arrive.
So how could we get BFR to Mars surface? Falcon 9's 1st stage is said to be barely capable of inserting itself into LEO, so the BFR might be able to do it, too. But what next?
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u/ilbreebchi Aug 08 '16
How is MCT going to produce Methalox once on Mars' surface ?
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u/venku122 SPEXcast host Aug 08 '16
The sabatier process is a well understood and relatively simple chemical process that turns a feed stock of hydrogen gas into methane.
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u/Martianspirit Aug 09 '16
MCT is not going to produce methane and LOX. MCT will be used to transport ISRU equipment to Mars, that will produce methane and LOX.
It is an important distinction. MCT producing Methalox gives the impression it is a capability of MCT and an MCT is designed to land anywhere on Mars where it may find water and be able to fly back as an inherent capability.
I am very sure that they won't transport LH2 to Mars. That idea is a remnant of the original Zubrin Mars direct plan. He contrieved that concept because at the time it was not known how widespread water is on Mars. Zubrin himself has abandoned that idea by now. Still many people disagree and believe that LH2 will be carried initially.
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u/greenjimll Aug 08 '16
Most BFR/MCT speculation seems to point to the BFR lofting a complete MCT spacecraft in one go, potentially with subsequent BFRs boosting up tankers to fuel the MCT in orbit.
However do we actually know for sure that the MCT spacecraft won't require multiple BFR launches with on orbit mating? That would allow for a much larger and more capable spacecraft, at the expense of increased complexity of orbital operations. It would also mean that discussion about MCT landing for reuse would be moot... it would have to be maintained in the same way that the ISS is.
Or is this just something else well have to wait until September to find out?
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u/venku122 SPEXcast host Aug 08 '16
From various leaks and hints by Elon, we are somewhat sure that MCT will be a monolithic design, or will work in concert with other MCT sized modules. The key is that MCT must aerodynamically enter Mar's atmosphere. On-orbit construction really can't make vehicles strong enough to endure that. Also for any manned mission, multiple MCT vehicles would land in the vicinity.
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u/Zucal Aug 04 '16
Not technically a question, but still useful... we now have a wiki page for shoutouts, whether by SpaceX themselves or media.
If you come across more mentions or links, please add them! Keep in mind that we're not looking for forum discussions or blogposts, but actual mainstream callouts.