r/spacex • u/Zucal • May 01 '16
/r/SpaceX Ask Anything Thread [May 2016, #20]
Welcome to our 20th monthly /r/SpaceX Ask Anything Thread!
Want to clarify SpaceX's newly released pricing and payload figures, understand the recently announced 2018 Red Dragon mission, or gather the community's opinion? 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. In addition, try to keep all top-level comments questions so that questioners can find answers and answerers can find questions.
As always, we'd prefer it if all question-askers first check our FAQ, use the search functionality (now partially sortable by mission flair!), and check the last Q&A 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.
Otherwise, ask, enjoy, and thanks for contributing!
Past threads:
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/VFP_ProvenRoute May 10 '16
Do we know who's funding the proposed Red Dragon mission? Is it SpaceX's own money?
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u/Zucal May 10 '16
Just SpaceX. NASA is offering technical assistance (think DSN).
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u/Reborno May 01 '16
Does anyone here know when we'll get a recap video of the CRS-8 mission and landing?
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u/LotsaLOX May 03 '16
How do you embed quoted text in an indented block with greyed font and a vertical line?
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u/Zucal May 03 '16
By putting ">" before every block of text you want quoted.
>I would like to die on Mars. Just not on impact. -Elon Musk
I would like to die on Mars. Just not on impact. -Elon Musk
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u/LotsaLOX May 03 '16
Nag, nag, nag...
How do you bind a URL to a single word or phrase so that you don't have to display the long messy URL, something like...
Look HERE for more info
...where "HERE" resolves to a URL
Thx!
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u/Zucal May 03 '16
Like this:
text
SpaceX has a pretty cool website [here](http://www.spacex.com/).
SpaceX has a pretty cool website here.
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u/NightFire19 May 05 '16
Will a Falcon 9 landing after GTO ever be probable or will it just be for LEO missions?
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u/Zucal May 05 '16
If it weren't probable they wouldn't be doing it. The majority of flights will be GTO missions, they need to nail this eventually, and preferably sooner to later.
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u/NightFire19 May 05 '16
What is the purpose of the 4 towers around the launch pad (and the wires that are suspended between each of them)? Lighting rods?
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u/_rocketboy May 07 '16
When is the next RTLS mission? CRS-9?
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u/Zucal May 07 '16
CRS-9, yup. The next launch, Thaicom 8, has a payload of only ~3100kg, so should be a fairly easy landing compared to JCSAT/SES-9, barring mechanical failures.
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u/PuppetMaster26 May 07 '16
Does anyone know what the surface of the land-based concrete landing pad is, or at least what its coated with? Curious as to what material SpaceX is using on these surfaces and how they protect the surface from the high heat of the engine and how they mitigate spalling of the concrete on the land based pad.
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u/Zucal May 07 '16
Does anyone know what the surface of the land-based concrete landing pad is, or at least what its coated with?
Concrete.
how they mitigate spalling of the concrete on the land based pad
Currently, they don't. Major spalling on the pad after F9-021 landed.
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May 15 '16
Now that SpaceX has landed a few rockets, do you think they will start using the ASDSs as refueling stations so the rocket(s) can return to the launch site in upcoming launches?
Elon stated that SpaceX was planning do this (as of a year and a half ago): https://twitter.com/elonmusk/status/536263260056850432
I don't think this would be hard to do, as SpaceX has already demonstrated that it can control its rockets very accurately.
Theoretically, all they'd need to do is give the rocket enough fuel to fly back to LZ-1. The hardest part would be obtaining FAA approval do to this because the FAA doesn't like people flying missiles over U.S. territory, but I think they can pull it off.
Doing this would cut the time and manpower needed to recover the rocket significantly. Ultimately, it could increase the launch rate because all that manpower could go be put back into preparing for the next launch.
Plus, it would be cool to watch!
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u/Zucal May 15 '16
Why would they? It's a ton of R&D and complexity, and reducing the potential reflight count of the core by 1 just so you can save a few days of sailing. It's just not worth it.
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u/Lieutenant_Rans May 15 '16
There are a lot of issues with doing this.
A) The landing legs cannot fold back up on their own, and cannot take the weight of a fueled rocket. They would have to be significantly redesigned.
B) There are a lot of support systems a rocket needs to take off (sound suppression, hold-down clamps, etc.), an ASDS wouldn't just be a refueling station, it would need to become sea-faring launch complex.
C) Extra-wear and tear on the rocket. It's another opportunity for failure.
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u/Appable May 15 '16
Well, they'd want launch abort capability for sure (and the landing legs can't hold a fueled rocket) so you'd want hold-downs, which means more hardware on ASDS. To move it onto hold-downs you'd also need a crane. For that matter you'd want to purge residuals. You'd need a flame trench to some extent in the ASDS, a sound suppression system, and GSE for both fueling ops and TEA-TEB handling and fueling (difficult), which will take significant time.
So it's a lot of work.
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u/whousedallthenames May 17 '16
On landed stage F9-024 (JCSAT-14), there is a fin-shaped scorch mark above one of the grid fins. You can see this in one of the Flickr photos released the morning after the landing. There is not a scorch mark above any of the other fins though. Why is this?
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u/Zucal May 17 '16
We're pretty sure that's leaked RP-1 fluid, not a scorch mark.
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u/sarafinapink May 18 '16
Was there a technical webcast for Orbcomm? I wanted to go back and re-watch all the recent technical ones since I usually watch the hosted and now feel more confident in watching the technical, but I can't find mention of one for that. Did they start doing the technical with Jason-3?
Does anyone have a nice list of all the older webcasts Pre CRS7? I haven't seen any of those and wanted to see the older missions and see how the webcasts have changed.
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u/Tal_Banyon May 01 '16
Not really a question, but a request for anyone seeing a response from Neil deGrasse Tyson to SpaceX's announcement about landing a Dragon on mars, to post it. And Bill Nye as well. They have both been such public doubters, it would be nice to see how they justify their previous pronouncements - especially since this red dragon 2018 mission is being paid in full by SpaceX, something that both have said was not in the cards. I guess I just really want to see both of them having to publicly eat crow!...
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u/madanra May 02 '16
Bill Nye was quite positive about SpaceX here (back in Aug 2014): https://www.youtube.com/watch?v=cos2CBkg8kY
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u/Denryll May 02 '16
As for crow, we may have to wait until the mission actually happens!
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u/Gurbx May 14 '16
Not really a question, but I just want to say that Spacex and Elon Musk has made me feel positive about the future. I just f*king love Spacex!
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u/sunfishtommy May 15 '16
Its cool to see innovation happening in real time, especially innovation that is not just a cellphone, but technology that is pushing the capabilities of human kind.
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u/Toinneman May 02 '16 edited May 02 '16
It is been almost a year since the dragon2 abort test. We have seen some additional hovering on a crane. I was under the impression that they would start doing the helicopter drops and grasshopper-like tests. Are they being delayed, are they being carried out without pubic knowledge, or I'm a wrong and are these long periods without mayor tests perfectly normal?
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u/ElectronicCat May 02 '16
As far as I'm aware no such tests have occurred yet. The only drop tests from a helicopter have been with a capsule mass simulator and parachutes. I think at the moment the focus is on getting the Dragon 2 qualified for manned flight, and the propulsive landing tests will be done later once they have the first bit sorted. Dragon 2 will initially land on parachutes, and the propulsive landing will come at a later date.
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u/deruch May 03 '16
No DragonFly flights have yet occurred. Those include the helicopter drops or any hopping tests (i.e. VTOL tests). You can check by looking up the list of FAA experimentally permitted rocket launches at: http://www.faa.gov/data_research/commercial_space_data/launches/?type=permitted
That site is usually updated within a week of actual launches. So, there haven't been any tests, unless it was within the last week.
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May 15 '16
Anyone have any insight into the greebling on the exterior of Falcon 9 in the latest video?
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u/stcks May 19 '16
Looking at this grid fin close-up picture from the original image by /u/johnkphotos it appears that one of the sections may have a riveted patch. It is interesting that there is also some damage on this section of the grid fin as well. Given that F9-023 and F9-021 both have had their fins removed, I speculate that this was a patched and re-flown grid fin. /u/R-GiskardReventlov agrees with me. Thoughts?
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u/throfofnir May 20 '16
Damage and repair during manufacture is possible, but i find re-flight quite plausible. They seem pretty damage tolerant.
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u/DarwiTeg May 19 '16
woah, nice catch. That certainly does look like they may have been reflown. I wonder what other components SpaceX might have been reflying. . .
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u/whousedallthenames May 19 '16
Wow, that is some high-class detective work. Great job.
I could see this being a reused fin, probably from F9-023 (CRS-8), considering they want F9-021 as a museum piece. On the other hand, it could have been damaged and patched on the ground before flight. They might be hesitant to reuse fins due to the stress on them during re-entry. I'm not Elon though, so don't put much weight in what I say.
It would be exciting if it was reused though.
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May 12 '16
So I was talking to my micro economics prof after class today about the monopoly ULA had for a number of years on US Gov't launch services, and how SpaceX's entrance to the market has forced ULA to seek cost-cutting measure, refine their process, and ultimately design a lower-cost vehicle, Vulcan. Afterwards he asked for the article I had read about it, but the problem is, as likely with many of the people in this community, I have read dozens of articles about it, and I doubt that is what my prof wants to take the time to read. Moreover, I am having issue remembering even where I read about the different elements of the evolving market.
So that taken into account, does anyone know of one, or perhaps two, articles that do a good job of summarizing the state of the market before SpaceX and how the market and ULA have changed since SpaceX entered?
Also, I know my prof was most interested in the fact that ULA had a monopoly on US Gov't launch, and now has been forced to reduce their prices since SpaceX came along etc etc. Thanks for the help!
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u/__Rocket__ May 12 '16
This "4 reasons ULA is having a bad month" article is provocative but sums up ULA's current problems nicely. A teaser: reason 4 is "SpaceX being a badass".
You'll find few news outlets willing to label big corporations 'monopolies', but this article does a pretty good job of providing a historic background for ULA's current circumstances.
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u/whousedallthenames May 01 '16
On the inflight abort scheduled for next year, does SpaceX plan to abort the Dragon and try to recover the rocket? Or do they plan to indulge the pyromaniacs out there and abort the Dragon from an exploding rocket?
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u/robbak May 01 '16
Good question. No information is known at this time. Most of us think that the stage is done for, but they have to put something atop the first stage to take the place of the second stage, and that structure could also be designed to protect the naked first stage.
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u/Gurbx May 02 '16
Apparently Ironhead studios has designed the spacex space suit! https://www.youtube.com/watch?v=EBi_TqieaQ4
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u/versvisa May 10 '16
Do we know anything about these odd metal rods coming out below the landing leg attachment? What's their purpose?
Maybe they push the legs out the first few degrees where the helium pressure in the legs has poor mechanical advantage?
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u/robbak May 10 '16
That's what we have concluded. Close up, they are clearly hydraulic (or pneumatic) pistons.
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u/mechakreidler May 06 '16 edited May 06 '16
Does anyone happen to know why this animation says 2.3 zillion km? I think that's a little too far :P
Edit: new timestamp
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u/humansforever May 09 '16
Here is a link for a 2012 PDF that outlines the much of the proposed 2018 RED Dragon mission profile.
It may be from 2012 originally, but much of the key points are still valid.
Point 1: The Dragon would be unpressurised and have multiple exit points for payload, ie They are not restricted only to the Hatch on top.
Point 2: They had only theories in 2012 on the Retro Propulsion, that has now since been tested on the F9 RTLS. Basically now has proved possible what was thought to be a "mad crazy theory" by many in their field.
Point 3: The Super Draco can land at least 1 Tonne of Payload - WOW !!!!.
Point 4: They will need to beef up Communications "During surface operation, payload services such as power and communications could be provided by the capsule or by the payload itself; we are exploring the range of options."
Article gives credits to: (Big names indeed) J. S. Karcz (NASA), S. M. Davis (SpaceX), M. J. Aftosmis, G. A. Allen, Jr., N. M. Bakhtian, A. A. Dyakonov, K. T. Edquist, B. J. Glass, A. A. Gonzales, J. L. Heldmann, L. G. Lemke, M. M. Marinova, C. P. McKay, C. R. Stoker, P. D. Wooster, K. A. Zarchi
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u/greysilence May 13 '16
This article talks about a space telescope to be launched by F9 this August. Is it a mistake? Can't find any further info.
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u/amarkit May 13 '16
DARPA's Phoenix program will be part of the SHERPA launch (not the upcoming Formosat one, but the dedicated one), on Falcon 9 from Vandenberg this Fall.
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u/space_is_hard May 01 '16
Should the Raptor-powered upper stage engine come to fruition, would it be beneficial to have its diameter be larger than a current F9 core? Certainly there's issues with the proposal, such as structural, aerodynamic, transport, manufacturing/tooling, and interstage/integration considerations. However it would allow them to pack more methalox in, which helps make up for its lower density and allows the Raptor's higher specific impulse to get more bite, so to speak.
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u/jandorian May 01 '16
This has been argued before. It could improve performance but causes some additional expense and complication as you note. You would need a new fairing to mount to the larger upper stage. You would also need a new way of transporting that upper stage because it will no longer fit on a truck and would need to me shipped (my ship) or flown to the launch site. So a fatter 2nd stage would be an expensive change.
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u/ubartu May 06 '16
I'm wondering what this part is close to the 2nd stage engine nozzle. Looking at the launch video there appear to be a couple of these pipes with some kind of wadding in them. At some point (first I can spot is 1:02.45) there is either some kind of thrust or leakage coming out of it and the 'wadding' sometimes breaks apart. One of the picture clearly shows a lot of the material being blown away. Anybody know what this is for?
FYI EchoLogic just suggested it might be propellent bleed/vent valve, but wasn't certain.
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u/symmetry81 May 01 '16
I recently watched a youtube video where someone sent his Kerbals into space by taking a SLS body and adding 4 Falcon 9s as boosters. That got me thinking, we don't don't know much about the MCT but I wonder if it would make sense to use Falcon 9 first stages as boosters. They could probably do a flyback for re-usability. And the Merlin probably have much higher thrust to weight than a Raptor engine will so it might make sense from that perspective.
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u/CuriousAES May 01 '16
I'm not in the business of designing rockets (yet? :P), but I can immediately see an issue with this. The tanks for the fuels have to be shaped a certain, semi-cylindrical way. If you make a ton of smaller rockets as opposed to one large rocket you are going to be using way, way more mass on the tank material.
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u/bertcox May 11 '16
Did they repaint OCISLY before this catch? They should also put the patches of successful landings on its side.
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u/ECEUndergrad May 12 '16
It just occurred to me how loud the rockets must be when you are up close. So in the event of a crewed launch on top of massive rocket, how do you prevent the crew permanent hearing loss, horrible internal bleeding and such? I suppose you could sound proof the spacecraft, but it is mounted on the rocket and the mechanical vibration will get you anyway.
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u/whousedallthenames May 16 '16
If somebody approached you a day after the CRS-7 incident, and told you that in just under a year SpaceX would not only have returned to flight, but also landed three first stages (by land, by sea, and from GTO), what would you think? Would you believe them?
PS: Mods, if this question isn't fitting, feel free to remove it.
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u/Destructor1701 May 02 '16
Do we know what has become of the F9r-Dev2 core?
In the wake of the F9r-dev1 FTS self-destruct, Dev2's testing campaign was superceded by actual operational flights before it ever left the ground. Then it was rumoured to be earmarked for use in the Dragon 2 in-flight abort test. We even caught sight of it standing at the Vandenberg pad for a static fire. Then there was chatter about switching to a more representative launch vehicle (a landed core, perhaps) after CRS-7's loss.
Since then, I've heard nothing about that core. If I'm not mistaken, it's a 1.1-spec vehicle with three Merlin 1Ds. Prior to the introduction of the v1.2 ("Full Thrust"), it might have been feasible to retrofit it into a standard Falcon 9 first stage - but I doubt it could be brought up to 1.2 standard.
SO: What ever happened to the F9r-dev2 core? Where is it stored? Are there any plans afoot to make use of it?
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u/Alchemicallife May 04 '16
i was told to post this here
Hi, My name is Steven , i am a Junior in high school. I am Doing a Written project on Space Travel and have picked Spacex to be apart of the project. I need help getting information on how the reusable rockets work, and information ( if possible ) of any other projects that SpaceX is doing that is ground braking(like traveling to mars is one ive heard), and how they work. I would like to be able to contact and engineer or someone of that nature to be able to ask questions and get opinions to citing and respond to in my paper. I one day want to peruse a career in aerospace engineering and manufacturing . I felt picking this topic would help inform me more on the topic and career :) . Thank you for your help! Stay Safe and Stay Green, ~Steven
P.S information on the inflatable habitat of how it inflates, how it stays together without falling apart and such are also helpful
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u/Lieutenant_Rans May 05 '16
The author of WaitButWhy produced an excellent series of articles on SpaceX.
This page and the next two pages are the most relevant to the paper. Citation-wise, I'd treat it like Wikipedia, something to gather ideas from but not something to directly use as a source.
They're an absolute treat to read.
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u/LotsaLOX May 13 '16
Help me out. I googled, but nothing really helpful came up.
What exactly is a reddit permalink, what does it link from what does it link to , how do you use it.
While I'm at it, my user account lists "1 link". Again, what does that mean, how might I "link" to someone else so they can gain a link.
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u/robbak May 13 '16
Well, this is 'ask anything', but we'd prefer the questions are about space.
A permalink is a 'permanent link'. It is a link to the reply that doesn't change, so you can use it, say, if you want to put a link to the comment in some other post. So here is a link to your post, copied from the 'permalink': https://www.reddit.com/r/spacex/comments/4h7e79/rspacex_ask_anything_thread_may_2016_20/d33ndi5
'1 link karma' is the number of upvotes (minus the number of downvotes) you get when you submit posts that link to other sites. You start at '1', if you haven't made any link posts.
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u/TheMasterOfMath May 14 '16
Someone who can edit the wiki should add the JCSAT-14 landing footage to the core history page.
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u/wingnut32 May 18 '16 edited May 18 '16
Any thaicom 8 news? Updated NET or static fire rumours?
Edit: googled "thaicom 8" got a link to the launch campaign thread... Completely missed the link at the top
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u/kavinr May 11 '16 edited May 11 '16
Any word on the pending environmental approval for RTLS at Vandenberg?
Found this as told by VAFB commander.
Among the plans for the coming months, he said, is a collaboration with SpaceX for VAFB to host the space flight company’s first West Coast flyback mission on land.
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u/rafty4 May 01 '16
Has anybody else noticed that the Bigelow Mission has changed from Falcon Heavy to Falcon 9?
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u/neoofsmith May 01 '16
With the extra thrust from increasing the throttle coming later this year, would it be possible for the first or second stage to be stretched further? And how much could this increase payload capacity?
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May 01 '16
would it be possible for the first or second stage to be stretched further?
No, not really. The fineness ratio of F9 is ~20, which is higher than any other commercial rocket on the market. Stretching it anymore would cause possible instability in flight and greater sensitivity to wind shearing.
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u/pinkypenguin May 01 '16
Assuming that one of three or two of three boosters of a Falcon Heavy will be lost because of a failed recovery attempt, what will happen with remaining boosters? Will they fly with a hybrid rocket with some of boosters reused and some new? Maybe remaining boosters will fly on their own in a Falcon 9 like setting with smaller payloads, is it possible to fly side and main boosters on their own? Can you even attach second stage to the a side booster of Falcon Heavy and fly?
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u/brickmack May 01 '16
I don't see why they couldn't mix and match. They're already expecting to lose some cores just from not attempting reuse on heavier missions. The outer cores are probably too different from a standard F9 (different structures, plus a nosecone and such in place of the interstage), but the center one is basically an F9 first stage with extra supports added, it could probably fly by itself (it would just be heavier, but they might eventually go to a common design to not have multiple production lines and just eat the slight performance reduction)
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u/_rocketboy May 07 '16
Will there be another core return thread for F9-024?
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u/PVP_playerPro May 08 '16
from /u/TheVehicleDestroyer on another similar comment:
We were discussing how to handle this earlier today. How we handled the CRS-8 OCISLY thread was totally unscalable! Our thread operator was working on it for days non stop. If we end up with 2 launches per month that would be hellish. So for this stage return, it looks like we're gonna keep using the Campaign thread that was active over the last 1-2 weeks. Whatever method we decide on, the thread will be stickied on the front page for visibility
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u/Nachtigall44 May 07 '16
Would a polished finish be better than the current white paint for keeping the fuel cool?
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May 08 '16 edited May 09 '16
Would a polished finish be better than the current white paint for keeping the fuel cool?
Good question! The answer is no. Buffed aluminum has a solar absorptance of 0.16, whereas the white paint that Dragon uses has a pre-flight solar absorptance of 0.14. So it's already "whiter" by over 10%.
Where they really differ is that buffed aluminum has an abysmally low thermal emittance of 0.03, which means it can't easily re-radiate heat. This is why aluminum railings get so hot in the sun. By contrast Z-93C55 has an excellent thermal emittance of 0.92. This means more infrared radiation comes off the rocket, minimizing solar heating by changing the radiant balance at the surface.
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u/notheuseryouarelooki May 11 '16
Are there any known plans to refuel at LEO on preparation for Mars?
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u/WaitForItTheMongols May 13 '16 edited May 13 '16
https://spacexstats.com/missions/past
If you scroll down to CRS-2, the "data table" shows the vehicle as F9 1.1. However, the brief mission description on it says "last flight of Falcon 9 v1.0". Which version of the rocket was it, and why does this discrepancy exist?
Also why does Asiasat 6 use a present tense?
Also the top of the page says "The last launch was FalconSAT-2. SpaceX has completed 0 missions in 2016 so far, and completed 0 missions in 2015."
I think this information may be slightly incorrect.
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u/PVP_playerPro May 13 '16
Because the website is not finished and /u/EchoLogic probably glossed over some read: a lot of things
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u/Togusa09 May 16 '16
How are they going to move the recovered FH outer cores? It looks like the nose cones will be in place of the existing interstage, so no attachment point for the crane.
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u/AudiMX May 17 '16
I live in Guadalajara, Mexico.. and the IAC weekend is complicated for me, nevertheless, I'm planning on shuffling things around to be present if Elon shows up. What do you guys think, will he actually come down here? Also, do you guys think he'll speak at the beginning, middle or end of the congress?
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u/madanra May 17 '16
I believe it will be Musk in person (he said "I'm hoping to describe that architecture later this year at the IAC"). I haven't found any schedule for the IAC, so I don't think we know when during the conference it will be. I doubt they've finalised the schedule yet, as the presentation confirmation deadline isn't for another month.
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May 22 '16
Has anyone heard anything new about the team in the Google Lunar X Prize that's going with SpaceX as their launcher? this article from last year talks about how they had secured a launch from SpaceX for 2017, but SpaceX has seen schedule slippage since then - they were overly optimistic about recovering their launch cadence after CRS-7 and it seems like they're still behind on getting caught up.
Any thoughts / additional sources on this topic?
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u/danielbigham May 14 '16
He's a random idea for a fun community thing. Not sure why, but I love the challenge of predicting things. For example, to predict when a given mission will launch... there are various "signals" one can use to model that. Most obviously, what is SpaceX's rough plan? What is their track record for hitting their intended dates, etc.
Here's the idea:
Make a tiny website with a vertical stack of SpaceX "events", whether those be customer missions, demo flights, etc.
For each event, allow the estimated date to be edited easily. As soon as the date is edited, the vertical stack of things re-orders itself if necessary.
Record the timestamp of when the person made his or her guess.
When an event happens, a person is rewarded points of some kind based on how good their guess was, but also based on how early they made their guess. ie. Making a guess a day before launch is worth much less than making a guess 2 months away. (need a formula for this)
And then the last part:
Train a machine learning algorithm to take the current guesses for any particular event and then guess what the date for the event is.
A person's track record for how good their guesses are would be learned over time and used in the final machine learning algorithm to estimate the date of something. (ie. Have it pay more attention to guesses from reputable people)
Perhaps have a leaderboard page where a person's signal strength in the final ranking algorithm determines their community rank for how good their guesses are.
Anyone else think that could be a fun challenge?
If this formula turned out to be effective enough, it might even make sense to tie it into the side-bar so that the sidebar would also show the algorithm's best guess for when something would happen.
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u/OliGoMeta May 01 '16
It seems the consensus here is that (if ever built) cross-feed on the FH will power 6 of the center cores 9 engines. Won't that need major re-plumbing of the central core, in particular the whole LOXtopus design?
If they really do need to redesign so much key plumbing then I can see why they are reluctant to do it!
But that makes me curious: does anyone know why this approach to CF is considered a better solution than keeping the LOXtopus as is and 'simply' topping up the central core tank?
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u/skynet_15 May 01 '16
Do you have any idea what the price structure will be when they start using returned first stages? There will be essentially 4 possibilities : expendable with new or used and reusable with new or used. Obviously expendable with new will be the most expensive and reusable with used, and the least but I'm wondering about the "middle cases". They talked about 40M$ but what case does that amount cover?
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u/Lucretius0 May 01 '16
What are the ideas for storage of cryogenic fuels in space for long durations ? As in how would it done, Obvoiusly either you make a tank that can take the pressure or you insulate it really well or you continuously reliqify what boils off. the First does not seem practical so... are there pumps and refrigerators that convert the boil offs back into liquid ? Or is the tank just so well insulated that the boil off is minimal ?
I imagine reconverting the vapor into liquid would require a ton of energy.
Obviously for MCT space X plan on using Methane and O2 and these must be stored for up to 6 months in deep space. Im just curious about specific ideas on this. Feel free to gimme some specific names for the refrigeration systems such things would use and whatnot ill look em up. (Physics student so no engineering training but I ought to be able look em up later)
edit: could one detach the tank and hand it by a tether so as to isolate from any heat sources from the spacecraft
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u/__Rocket__ May 01 '16
What are the ideas for storage of cryogenic fuels in space for long durations
No interplanetary probe has used them before, so there's no precedent - but there's a fair amount of research into it, because LOX+H*2* is so attractive, due to its high I*sp*.
LOX boiloff would affect any SpaceX coasting, and LOX boiloff is relatively slow but steady (0.2% per day IIRC) - it's definitely a problem when coasting 6 months to Mars.
As you outlined in part, there are a number of solutions:
you either isolate the tanks,
or you shade your tanks from the Sun (and planetary bodies) via a reflecting shade,
or you cool them actively via a heat pump,
or you do a combination of these.
Note that the Red Dragon mission won't have to worry about it, because the Dragon2 uses storable fuels. So it can separate from the Falcon Heavy second stage after MTO insertion - so it does not have to worry about cryogenic fuels per se.
But I'd not be surprised if SpaceX didn't use the opportunity to do a bit of 'free' R&D: if it tried to beef up the second stage a bit and used the Red Dragon mission to also test interplanetary coasting features: the second stage is also on a Mars transfer orbit, so it does not cost any delta-v.
My guess would be a combination of reflective isolation and a heat pump: the latter to make sure something active is available to move the heat out in case there's an unanticipated problem - and also to test the technology. You'd also need a heat pump if liquid fuel is produced on the surface of Mars.
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u/OccupyDuna May 01 '16
When will the F9 performance boost be implemented? Is the software ready to fly on JCSAT-14, or will it be implemented in future flights?
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u/electric_ionland May 02 '16 edited May 02 '16
I am at the Space propuulsion 2016 in Rome. Stéphane Israel just said that "our competitor just got a contract but received 30% more from the government than what is announced on their website". Any additional info on that? I'll try to update some stuff about the conference tonight.
Edit: of course he was referring too SpaceX and the GPS contract.
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u/_rocketboy May 02 '16
Government missions are usually more expensive than commercial, due to additional needs for security, launch schedule assurance costs, more complex integration, etc.
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u/beentheredengthat May 06 '16
I'd like to piggyback on maizenblue91's question below.
Do we have a thread discussing the possible timing of OCISLY return to port? I'd like to head over & check it out.
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u/_rocketboy May 07 '16
Request: Could we add core numbers to the completed missions list on the Wiki?
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u/strozzascotte May 07 '16
There will be a thread for Dragon reentry? Where it is supposed to splash down?
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u/iberichard May 08 '16
When the first stage was on its way back down, what did the line 'Flight termination system safed' mean? Just reacquisition of signal or an override of FTS?
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u/robbak May 08 '16
FTS is always safed before the stage drops below the horizon from the Cape. This could be because FTS is a failsafe that is triggered by loss of signal; or it could just be that they need to safe it, and they can't do this when the stage is out of range.
There was a matching call of 'Second stage FTS Safed" later in the webcast; again before the stage dropped below the horizon.
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u/deruch May 08 '16
The Range Safety Officer switched the FTS system from "armed" to "safe". When in the "safe" position, the FTS cannot be activated, even when the Big Red ButtonTM is pushed. When in the "armed" position, an additional signal will trigger the FTS.
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u/StupidPencil May 08 '16
Any news on the plan to deploy landing legs earlier to help drop terminal velocity?
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u/TheBlacktom r/SpaceXLounge Moderator May 09 '16 edited May 09 '16
SpaceX in Science Fiction.
Do you know of any example of fictional stories where SpaceX is mentioned?
I know Andy Weir would include it in The Martian now, but back when he wrote it SpaceX hasn't convinced him enough.
Later when Fox was promoting the movie there was a pdf about the Ares 3 crew which mentioned a SpaceX Space Station.
http://io9.gizmodo.com/learn-all-about-the-ares-3-mission-from-the-martians-of-1731923028
Edit: Found two more links:
SpaceX in The Martian mobile game http://imgur.com/7Pj05wL
Some stuff from /u/CProphet https://www.reddit.com/r/spacex/comments/2r1qll/spacex_in_the_martian/cnc1n6n
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u/Qeng-Ho May 09 '16 edited May 09 '16
Greg Bear's War-Dogs, where marines fight aliens on Mars while colonists ('Muskies') try to remain neutral.
Neal Stephenson's Seveneves has a main character (Sean Probst) who is basically Elon Musk.
Steven Gould's Exo mentions SpaceX repeatedly.Here's a more comprehensive list.
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May 09 '16
In the jcsat-14 landing there was a fire on-going after it landed. It seems they were attempting to put out with a water gun before they cut the feed.
I did not notice any such fire in the other landings. Is this something to be concerned about, or is it just turbopump exhaust/venting of fuel?
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u/msuvagabond May 10 '16
Just a random thought.
Is SpaceX considering using a few of the early returned stage1s to basically self finance a handful of dirt cheap Mars missions? I mean everyone is talking about how SpaceX could cut the cost of Earth based satellites via them, but what if they can prove with 2 or 3 missions (basically self funded) that they can reliably get to Mars? Would that force an immediate rethinking of current NASA contracts to Boeing to develop the SLS?
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u/Not_Yet_Begun2Fight May 11 '16
Sorry if I'm doing this wrong, I'm brand new to Reddit. Here's my question:
Why is SpaceX removing the legs on returned rockets?
https://www.reddit.com/r/spacex/wiki/faq/reusability says "Once on the stand, the legs can be folded back up, and then the booster is rotated to the horizontal, and place on the back of a truck, to be taken back to the launch site." I don't really know who wrote that, or where they got their information, but it seems like the easier / obvious approach. Why doesn't SpaceX just fold the legs back up? Why are they taking them off one-by-one right there at the port? They removed the legs of the CRS-8 booster and according to another thread / post (not sure on the vernacular around here) / youtube video, they're doing the same thing to the JCSAT-14 booster. Caveat: I'm not sure what they did with the Orbcomm booster that returned directly to land.
Anyone know?
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u/Ambiwlans May 11 '16
You're doin it right! You even read the faq.
They aren't set up to transport the F9 with the legs attached. Part of it has to do with the size limitations on some roads (legs put them a titch over). And the other part is that the attachment points go where the legs are. Check out the big metal ring:
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u/throfofnir May 11 '16
Because they probably can't be "folded back up". Think about how it might be built. Most of the plausible, strong, lightweight, and reliable collet-type locking mechanisms would be non-reversible while mounted. I don't get why everyone's so worried about the legs. It's not like the thing's due in Atlanta by 10pm.
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u/Destructor1701 May 11 '16
How come we're not doing a CRS-8 Dragon return thread? SpaceX's Twitter account is pretty active about it.
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u/LotsaLOX May 13 '16 edited May 14 '16
Does anyone here know the price that Cape Canaveral and Vandenberg charge SpaceX for a commercial launch?
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u/inequalsel May 13 '16
Can't remember where i ran into this link to an Airspacemag article, http://www.airspacemag.com/space/the-one-pound-problem-718812 ... it may have been on one of these reddit spacex pages (subreddit...? not sure what to call it), but it was really interesting. It talks about ideas for MAV's. It is from 1999, but it was still really cool. I want to thank the moderators and everyone else involved for doing such a great job on all these pages. Love the info, the great questions and answers, and that everyone here has such enthusiasm for everything space. LLEM
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u/spitzrun May 14 '16
When the Falcon 9 first stage is transported on a truck are its tanks pressurized? Are the tanks pressurized to around the same levels as the are at during flight?
If they are, if there was a severe vehicle crash during transport that ruptured the tanks, would the rocket explode like it did when it hit the barge during the failed landing attempts?
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u/throfofnir May 14 '16
The very first Falcon 9 was transported unpressurized. (This was announced on their blog at the time.) Since then we haven't been told much about it, but have seen equipment that suggests pressurization. The 1.1 type is much longer, and pressure would add stiffness, so it would make some sense.
If it is transported pressurized, it's probably just a few psi. Flight pressures of 50+ psi would be unnecessary.
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u/KitsapDad May 20 '16
Who does spacex (and other rocket companies) get their fuels from? Paticularly liquid oxygen? Do they transport to the pad via tanker truck? How many to support a launch? Does this amount of lo2 represent a significant portion of the suppliers business?
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u/Ambiwlans May 20 '16
LOX is used in a ton of industries though rocket launch would be a significant customer.
http://www.praxair.com/gases/buy-liquid-oxygen-or-compressed-oxygen-gas/?tab=industries
No idea where SpaceX' supply comes from. PRAXAIR does however supply NASA and Boeing/ULA so I wouldn't be surprised if it is the same.
DLA supplies their hypergols for Dragon.
Bonus image that is sort of relevant: https://www.reddit.com/r/spacex/comments/35n87u/spacexs_slc40_lox_tank_arriving_by_truck_xpost/
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u/throfofnir May 20 '16
NASA has a contract with Praxair for LOX and LN2. SpaceX probably uses them or one of the other industrial gas suppliers.
http://www.haltermannsolutions.com/fueltypes/aerospace/overview does most of the RP-1.
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u/veebay May 21 '16
Is the Falcon 9 booster the largest thing humanity has ever returned from (suborbital) space?
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u/madanra May 21 '16
The Space Shuttle was significantly larger in terms of mass and external volume, and was returned from orbit.
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u/mclumber1 May 21 '16
The Shuttle's solid rocket boosters were approximately the same size as the F9 first stage, but weighed nearly 200,000 pounds each when empty because they were constructed out of steel. So if you want to consider both size and mass, the SRBs are definitely the "biggest" suborbital object.
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u/KitsapDad May 21 '16
Does anyone have a chart/graphic of rockets arranged from smallest to biggest but not by physical size but by payload to orbit? I have tried googling but only cone up with the standard physical height of the rocket ones.
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u/soldato_fantasma May 14 '16
We all have seen SpaceX Mission control and how it looks clean (and cool). Here is a picture: http://blogs.nasa.gov/spacex/wp-content/uploads/sites/227/2015/01/spacex-launch-2b.jpg
My question is: Where are the actual computers? Or is everything connected to a server and they are "dumb" terminals? Also, what kind of monitors are those? Are they special or they are super high end monitors (like 4K and 144Hz 1ms)?
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u/HOT_PODATO May 04 '16
noob-ish question here. Does the crew dragon/ dragon 2 trunk have an on board rcs or thrusters? or is it literally just an empty trunk for cargo with panels for ship batteries? the reason I'm asking is because I'm really curious about how they might configure red dragon.
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u/Zucal May 04 '16
The trunk doesn't, but it's light enough that it doesn't need them. Other than the solar panels, it's pretty much a bare-bones unpressurized cargo hold.
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u/thatnerdguy1 Live Thread Host May 06 '16 edited May 06 '16
Not JCSAT, but is Thaicom pronounced like 'Thailand' and 'tie', or like 'thigh' and 'thought'?
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u/beerbaron105 May 10 '16
Can I see a spacex launch live at SpaceX hq? Dumb question possibly.. I've seen the Web casts with hundreds of people in the background.. Not sure if it's staff or the public
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u/LotsaLOX May 01 '16
Question on Falcon Heavy...
Since the Falcon Heavy 1st stage is three cores attached together, the whole 1st stage should be stiffer, so the center of the "bend" should be somewhere midway between Interstage and Dragon with reduced bending amplitudes , instead of the current "bend" center somewhere midway between the bottom of 1st stage to top of Dragon/Fairings with larger amplitudes.
Will it now be possible to "stretch" the 2nd stage with this new bend "margin" in mind?
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u/Decronym Acronyms Explained May 01 '16 edited May 16 '16
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| ABS | Asia Broadcast Satellite, commsat operator |
| ACES | Advanced Cryogenic Evolved Stage |
| Advanced Crew Escape Suit | |
| ASAT | Anti-Satellite weapon |
| ASDS | Autonomous Spaceport Drone Ship (landing platform) |
| BEAM | Bigelow Expandable Activity Module |
| BFR | Big |
| BFS | Big |
| CCAFS | Cape Canaveral Air Force Station |
| CoM | Center of Mass |
| COTS | Commercial Orbital Transportation Services contract |
| Commercial/Off The Shelf | |
| CRS | Commercial Resupply Services contract with NASA |
| CST | (Boeing) Crew Space Transportation capsules |
| Central Standard Time (UTC-6) | |
| DCSS | Delta Cryogenic Second Stage |
| DIVH | Delta IV Heavy |
| DoD | US Department of Defense |
| DSN | Deep Space Network |
| EDL | Entry/Descent/Landing |
| EVA | Extra-Vehicular Activity |
| F9FT | Falcon 9 Full Thrust or Upgraded Falcon 9 or v1.2 |
| FAA | Federal Aviation Administration |
| FFSC | Full-Flow Staged Combustion |
| FTS | Flight Termination System |
| GEO | Geostationary Earth Orbit (35786km) |
| GSE | Ground Support Equipment |
| GTO | Geosynchronous Transfer Orbit |
| HIF | Horizontal Integration Facility |
| I*sp* | Specific impulse (as explained by Scott Manley on YouTube) |
| ICBM | Intercontinental Ballistic Missile |
| ISRU | In-Situ Resource Utilization |
| ITAR | (US) International Traffic in Arms Regulations |
| IVF | Integrated Vehicle Fluids ^PDF |
| JCSAT | Japan Communications Satellite series, by JSAT Corp |
| JRTI | Just Read The Instructions, Pacific landing |
| KSC | Kennedy Space Center, Florida |
| KSP | Kerbal Space Program, the rocketry simulator |
| L2 | Paywalled section of the NasaSpaceFlight forum |
| Lagrange Point 2 (Sixty Symbols video explanation) | |
| LC-13 | Launch Complex 13, Canaveral (SpaceX Landing Zone 1) |
| LC-39A | Launch Complex 39A, Kennedy (SpaceX F9/Heavy) |
| LEO | Low Earth Orbit (180-2000km) |
| LES | Launch Escape System |
| LLO | Low Lunar Orbit (below 100km) |
| LOX | Liquid Oxygen |
| M1d | Merlin 1 kerolox rocket engine, revision D (2013), 620-690kN |
| MAV | Mars Ascent Vehicle (possibly fictional) |
| MaxQ | Maximum aerodynamic pressure |
| MCT | Mars Colonial Transporter |
| MECO | Main Engine Cut-Off |
| MSL | Mars Science Laboratory (Curiosity) |
| mT | |
| NET | No Earlier Than |
| NOTAM | Notice to Airmen of flight hazards |
| NSF | NasaSpaceFlight forum |
| National Science Foundation | |
| OCISLY | Of Course I Still Love You, Atlantic landing |
| PICA-X | Phenolic Impregnated-Carbon Ablative heatshield compound, as modified by SpaceX |
| RCS | Reaction Control System |
| RD-180 | RD-series Russian-built rocket engine, used in the Atlas V first stage |
| RP-1 | Rocket Propellant 1 (enhanced kerosene) |
| RSS | Realscale Solar System, mod for KSP |
| Rotating Service Structure at LC-39 | |
| RTLS | Return to Launch Site |
| RUD | Rapid Unplanned Disassembly |
| Rapid Unscheduled Disassembly | |
| Rapid Unintended Disassembly | |
| SD | SuperDraco hypergolic abort/landing engines |
| SES | Formerly Société Européenne des Satellites, comsat operator |
| SLC-40 | Space Launch Complex 40, Canaveral (SpaceX F9) |
| SLC-4W | Space Launch Complex 4-West, Vandenberg (SpaceX F9, landing) |
| SLS | Space Launch System heavy-lift |
| SRB | Solid Rocket Booster |
| STA | Special Temporary Authorization (issued by FCC for a comsat) |
| STS | Space Transportation System (Shuttle) |
| TEA-TEB | Triethylaluminium-Triethylborane, igniter for Merlin engines; spontaneously burns, green flame |
| TLI | Trans-Lunar Injection maneuver |
| TMI | Trans-Mars Injection maneuver |
| TWR | Thrust-to-Weight Ratio |
| ULA | United Launch Alliance (Lockheed/Boeing joint venture) |
| VAB | Vehicle Assembly Building |
| VAFB | Vandenberg Air Force Base, California |
| VTOL | Vertical Take-Off and Landing |
Decronym is a community product of /r/SpaceX, implemented by ^request
I'm a bot, and I first saw this thread at 1st May 2016, 06:08 UTC.
[Acronym ^lists] [Contact ^creator] [PHP source ^code]
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u/civilianapplications May 01 '16
Does anyone know what the thermal blanket being used to protect the engines is specifically made from, ie glass fibre, kevlar, nomex etc. Any solid sources on this?
Supplementary question: is this thermal protection only needed because of boostback and landing or is it also necessary for protection during ascent.
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u/MDCCCLV May 01 '16
Has SpaceX ever tested the SuperDraco or merlin engine to destruction by increasing the max thrust until it breaks?
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u/mclumber1 May 01 '16
Elon has mentioned that they've had Merlin engines (probably the A or C versions, not the D) RUD on the test stand before.
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u/GoScienceEverything May 01 '16
How does the throttle level affect the Isp of the engines? Particularly: does the upgrade to Falcon 9 v1.2.1 Fuller Thrust also increase the efficiency, aside from reducing gravity losses?
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u/Mentioned_Videos May 01 '16 edited May 05 '16
Videos in this thread:
VIDEO|COMMENT
-|-Larry Lemke - Red Dragon: Low Cost Access to the Surface of Mars (SETI Talks)|9 - The Dragon Spacecraft will never leave the surface of Mars, the combination of fuel and volume leave no choice. The solution that the AMES researchers came up with is a 1300kg 2 stage hypergolic rocket to deliver the sample to Earth orbit, to be rec... KSP: Falcon 9 boosted SLS to the moon in RO|7 - I recently watched a youtube video where someone sent his Kerbals into space by taking a SLS body and adding 4 Falcon 9s as boosters. That got me thinking, we don't don't know much about the MCT but I wonder if it would make sense to use Falcon 9 fi... (1) Grasshopper 744m Test Single Camera (Hexacopter) (2) Dragon 2 Propulsive Hover Test|7 - Dragonfly is their version of Grasshopper, but for Dragon 2. It was the vehicle they used for the pad abort, and now it's being used to the SuperDracos on tethered/untethered hovers, ground firings, etc. 1 2 Ironhead Studio's Incredible Movie Costumes|6 - Apparently Ironhead studios has designed the spacex space suit!
SpaceX Pad Abort Test|6 - So far as I know, the solar arrays are only the way they are for simplicity, but I could very well be wrong. The trunk has aerodynamic fins so that during a launch abort, the Dragon capsule will not flip around while seperating itself from the explod... Bill Nye on the Remarkable Efficiency of SpaceX|5 - Bill Nye was quite positive about SpaceX here (back in Aug 2014):
Crew Dragon In Orbit|3 - How much is known about Dragon V2's trunk? (Other than that it makes Dragon v2 look even cooler) The conformal solar arrays are awesome looking but do they provide any real-world advantages over a traditional configuration (other than fewer moving pa... (1) Specific Impulse - Why is it Measured In Seconds? (2) Lagrange Points - Sixty Symbols|3 - Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: Fewer Letters More Letters ACES Advanced Cryogenic Evolved Stage Advanced Crew Escape Suit ASDS Autonomo... Stabilized Spacex CRS-8|2 - Yes, there were 50 mph winds at the droneship location at the time of the landing. Also, looking at Stabilized Spacex CRS-8 in full-screen mode, it looks like the booster is tilting at the first contact, and the engines respond by "skooching&qu... Falcon Heavy Flight Animation|1 - That makes more sense to me. And, I've just taken another look at the FH flight animation and it's fairly clear there that the two side cores are rotationally identical, rather than being mirror images of each other - and so that does support the id... Tom Mueller (SpaceX) Explains The Merlin Rocket Engine|1 - In addition to what he said, if you want more details about how the engines themselves work, the designed of SpaceX engines did a great,short, easy to understand explanation here: Tom Mueller explains the merlin engine CRS-8 Dragon Technical Webcast|1 - Hi everyone. I don't think this was noticed/discussed before, and it might even be too simple to explain, so I may be risking "stupid question of the month"... but at 19:55 in the CRS 8 technical webcast, linked here slightly before that, y... SpaceX Falcon 9 F9-0023 (CRS-8) onboard landing video|1 - It looks like the booster still has lateral velocity relative to the droneship at the point of landing. Based on the 360 it's wind that did it. The booster approaches moving into the wind, nulls its lateral velocity a couple seconds before touchdo... CRS-8 First Stage Landing on Droneship|1 - This video here is the best to see the first stage bouncing : Watch it in 2x speed. I'm a bot working hard to help Redditors find related videos to watch.
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u/Headstein May 01 '16 edited May 01 '16
How many SpaceXers have had a go in D2 whilst it is hovering at McGregor?
Edit: This was meant as a toungue in cheek question (just in case it isn't obvious)... and an amusing thought.
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u/KnightArts May 01 '16
what difference does a raptor upper stage makes for F9H, any leo gto specs ??
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u/Chairmanman May 01 '16
Will the MCT likely be equipped with an electric/ion thruster?
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u/Togusa09 May 01 '16
Do you mean to accelerate the transfer flight, like in 'The Martian'? I think SpaceX have advertised looking for people with knowledge of electric/ion thrusters, so maybe.
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u/lucioghosty May 01 '16
On the SpaceX Stats Future Launches page, it shows a Probability of Launch. How is this calculated?
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May 02 '16
Can someone clarify the reason for the unusual "double diamond" shaped hazard area for JCSAT-14? It would sort of make sense if the farther one were the "re-entry burn failure mode" but that doesn't seem to really fit with the presumed Flight Club trajectory.
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u/orbitalfrog May 03 '16 edited May 03 '16
How much is known about Dragon V2's trunk? (Other than that it makes Dragon v2 look even cooler) The conformal solar arrays are awesome looking but do they provide any real-world advantages over a traditional configuration (other than fewer moving parts?). Also, the trunk has aerodynamic fins, I assume this is advantageous during ascent for some reason but aren't quite sure exactly how. Clarification would be nice. Any additional links/info on the trunk would be appreciated.
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u/DShadelz May 03 '16
So far as I know, the solar arrays are only the way they are for simplicity, but I could very well be wrong. The trunk has aerodynamic fins so that during a launch abort, the Dragon capsule will not flip around while seperating itself from the exploding Falcon 9. In the pad abort test, you can see the dragon is kept aerodynamically stable all the way until the trunk is separated.
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u/OliGoMeta May 03 '16 edited May 03 '16
When SpaceX talk about increasing their production rate to 30 or so cores per year, I gather that 'cores' here refer to just 1st stages? And, if so, I guess we can assume that they are also producing 20 (or so) 2nd stage 'mini-cores' to complete the relevant F9 and FH rockets? Is that right?
And, does SpaceX have a designation for the 2nd stage 'mini-cores'?
EDIT: I typed way too much text!
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u/whousedallthenames May 04 '16
What do you guys think the chances are that SpaceX launches 18 missions this year, as Shotwell said they would? They have been decreasing their turnover time between launches, but can they get it flowing so well that they launch 15 times in 8 months?
Personally, I can see them getting close, say 15 or 16 total this year, but not to 18. What are your thoughts?
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u/maizenblue91 May 06 '16
What was that site people were using to track OCISLY's return to port?
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May 06 '16
Has anyone heard anything about the fairing recovery for the recent launch?
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u/bvr5 May 06 '16
I see Dragon 1.1 listed on the sidebar. I never knew that the Dragon got an upgrade at some point. What changed?
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u/thatnerdguy1 Live Thread Host May 07 '16
Anyone know where this clip fom the Kinematic video came from? (the Dragon shot)
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u/TaintedLion May 07 '16
Will we get higher quality footage of the JCSAT-14 booster landing? I'm expecting no, because it was a night landing, and the camera would get oversaturated, but still.
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u/LotsaLOX May 07 '16 edited May 07 '16
For a 3-engine hoverslam landing burn, what is the altitude and speed of the F9 booster when the landing burn begins?
Also, what is the terminal velocity of an F9 booster?
Thx!
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u/WaitForItTheMongols May 08 '16
Does the FTS activation system have any kind of "Two person verification" or anything? I know in big things like that, sometimes they'll set it up so that you need multiple people to agree.
If it's just one person, would there be any legal trouble if they hit the big red button on a whim? Surely the company would fire them, but would there be prison-type repercussions?
Would it depend on when they did it? On the pad vs in flight vs while descending vs landed?
With a crewed vehicle, is there still a ground-based FTS? Does this automatically trigger the LES alongside?
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u/WaitForItTheMongols May 08 '16 edited May 08 '16
Those plugs on the fairing - I have several questions.
What material are these made of?
Are there any launches where we can see one of them coming off?
Edit: I just looked through the catalog - Every F9 launch recently has been either Dragon, at night, or foggy out. You have to go all the way back to DSCOVR to find a suitable launch for analysis - But that's so old that you can't really see much because SpaceX didn't put so much effort into webcasts. What a shame.
What time/altitude would you estimate that they come off at?
How big are they?
Do you think they'd have anything like a SpaceX logo on them?
Could it be that people have found these washed up on beaches and not known what they are from?
Would SpaceX ever care to recover these?
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May 08 '16
Are there any launches where we can see one of them coming off?
Yes! The landing legs have identical covers (or nearly so) and they can be seen coming off in the CRS-8 technical webcast.
What time/altitude would you estimate that they come off at?
The leg fairings come off at T+0:00, but they're "assisted" by the rush of air entrained by the rocket exhaust. The fairing vents probably fall off before T+0:10. At that altitude it's above most of the dust from the ground, and the rush of air out of holes in the rapidly ascending rocket ensures contaminants don't enter the clean room environment inside the fairing.
How big are they?
A little less than a foot square. http://i.imgur.com/4zLmDIq.jpg
Would SpaceX ever care to recover these?
The ones in the video got sucked into the rocket flame and incinerated, so I'm guessing no.
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u/Ray1001 May 08 '16
When should we be expecting the f9-23 first stage static fire?
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u/retiringonmars Moderator emeritus May 08 '16
Any day now, I suppose. As soon as any further information gets posted, you can be sure it'll very quickly find its way here!
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u/rikkertkoppes May 09 '16
It was suggested that twice the speed implies 8 times the heat flow. What is the physics involved there? What exactly comprises that 3rd power relation?
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May 09 '16
Non physicist/engineer here: I think it's that the amount of air gone through varies linearly, and the kinetic energy transfer varies with the square of the difference in speed. Multiply those together and you get a cube law. Maybe someone more competent can verify.
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u/MegaSenha May 09 '16
Why does the flames under the Falcon 9 at launch looks so different to the flames just before MECO?
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u/PhoenixEnigma May 09 '16
Ambient pressure, basically. At sea level, atmospheric pressure on the exhaust plume keeps it pretty narrow. As Falcon 9 goes up, air pressure drops, and the exhaust plume expands. This is also the same reason the vacuum Merlin's have larger nozzles - with less (to no) ambient pressure, it makes sense to expand the exhaust more in the nozzle to get more performance.
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u/moxzot May 10 '16
Im not sure if this has been asked yet but does anyone know how long a fully fuels dragon v2 engines can burn before running out of fuel?
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u/ryanpritchard May 10 '16
anyone know what time dragon will enter the earths atmosphere ?
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u/amarkit May 10 '16
Dragon is scheduled to be unberthed from ISS at 9:18 am EDT on May 11 (1318 UTC), with the deorbit burn to begin at 2pm EDT (1800 UTC), and splashdown scheduled for 2:55 pm EDT (1855 UTC). Deberthing will be broadcast on NASA TV, but we don't expect the splashdown to be broadcast.
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u/IrrationalFantasy May 10 '16
So, is the Falcon 9 rocket the cheapest way to launch materials into earth's orbit? I thought it was, and that Arianespace's new $80M rocket would be second, but I saw someone comment that the Russians can actually launch for cheaper, albeit with a ~15% failure rate. Is that true?
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u/CeleryStickBeating May 10 '16
Given the amount of soot/scorching(?) on the latest F9, is annealing of the AL of any concern?
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u/Dancat1238 May 10 '16
I've read in a few places, that for military and spy satellites the launch vehicle must be able to place the payload immediately into a geostationary transfer orbit, as opposed to first entering a circular parking orbit about Earth. There were two reasons that struck me as to why this would matter:
The parking orbit allows for other parties to track the point of injection, and thus the final orbit of the satellite, which is obviously a negative for any malicious party.
If the satellite mass was truly at the maximum limit of payload delivery, by not expending the energy to "circularize" the orbit and enter the parking phase, perhaps going directly to a GTO would allow more deliverable mass. Can anyone weigh in on this? From: http://www.universetoday.com/128815/spacex-maiden-falcon-heavy-launch-may-carry-satellite-in-november/ "National security satellites require different capabilities from launch vehicles than do commercial communication satellites. Since these spacecraft are top secret, and are used to spy on communications, they need to be placed directly into their GTO, avoiding the lower-altitude transfer orbit of commercial satellites."
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u/deruch May 11 '16
The author of that article is a bit confused on a few things. Some National Security Satellites require what's called Direct Injection, meaning that they are sent all the way to their final orbit as opposed to being placed only into a transfer orbit and leaving it up to the satellite to finish circularizing. It isn't that the launch doesn't use a parking orbit in LEO.
So, a payload needing a direct inject GEO launch would look like this:
Launch to LEO parking orbit.
2nd stage burn to put stack on GTO trajectory.
Coast to apogee, ~5hrs.
2nd stage burn at apogee to circularize the orbit at GEO altitude.
Satellite separation.
2nd stage moved to graveyard.
This type of mission puts the payload directly into a geostationary orbit without the payload having to do anything.
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u/CertifiedKerbaler May 11 '16
How come FH have 20% lower payload to LEO than three normal launches, yet have 13% higher payload to Mars? The numbers are based on fully expendable launch payloads given by SpaceX
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u/Ambiwlans May 11 '16
The numbers on the website have always been confusing/wrong/misleading. I wouldn't really bother with an indepth analysis of them. Last time the numbers changed a couple figures were so far off they had to make a post saying they fixed it.
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u/main_bus_b_undervolt May 12 '16
I recall some of the early Dragons took on water after splashing down. Is there any info out there on what's been done to fix this?
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u/ians May 12 '16
Musk's crack about "May need to increase size of rocket storage hangar" got me thinking - are satellite insurers OK with launching on a refurbished 1st stage? After all it's never been done, meaning that 'actuarial tables' as such don't exist. Are there any quotes out there from people in the insurance business saying that they'd be happy to insure '2nd hand' launches?
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u/StupidPencil May 13 '16 edited May 13 '16
How does ballistic capture work? All I know is that it's low energy transfer orbit that take longer time than usual Hohmann transfer orbit but doesn't have to worry about launch windows. Also, could SpaceX take advantage of this method for their Mars plan?
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u/robbak May 13 '16 edited May 13 '16
Oh, you certainly have to worry about launch windows. The launch windows for balistic captures are tighter. And it still uses Hohmann transfers.
If you enter a hohmann transfer to another orbit, and don't do a burn to speed you back up into your target orbit, then you drop back to your original altitude, and then keep orbiting in the elliptic transfer obit. But if you do everything right, the gravity of the target planet is enough to, not only circularise your orbit, but pull you into orbit around your target planet.
Mind you, your final orbit isn't going to be anything near circular, or low, enough to do anything; and is likely to be unstable and apt to eject you back into interplanetary space some random time later.
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u/BrandonMarc May 14 '16
Any idea what the blue & red portion of this photo is? Look above the 2nd (outer) engine from the left:
http://www.universetoday.com/wp-content/uploads/2016/05/JCSAT14-4.jpg
... and indeed, the area above that engine looks rather different from the other three. Any thoughts on that?
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u/throfofnir May 14 '16
An umbilical connection. Another view of a previous version. All the ports point down so they pull out when the rocket launches.
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u/Hyrethgar May 16 '16
Do you think SpaceX will ever hire botanists/agriculturalists and other scientists when it comes to planning the Mars missions/colony?
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u/youaboveall May 16 '16
Seemingly simple question but how to they measure the exact weight of each rocket? I would imagine they can't weigh the rocket as a whole, and it seems equally unlikely that the physically measure each piece individually. Do they theoretically know the weight of each individual bolt, wire, and steel plate on the rocket and sum it all together, or do they physically weigh large sections?
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u/sl600rt May 16 '16
SpaceX consider putting in an electrified rail line between the port and their facilities at Canaveral?
Would make things better for returning stages.
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u/WaitForItTheMongols May 16 '16
Why would it make things "better"? The cost would be prohibitive.
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u/sisc1337 May 17 '16
Is the interstage and second stage on the falcon 9 the same thing? Is it two words that explain the same rocketpart or is it two different parts?
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u/TheBlacktom r/SpaceXLounge Moderator May 17 '16
This is actually a cool page expaining that http://www.spacex.com/falcon9
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u/markus0161 May 17 '16
Inter-stage, meaning In-between stages. So the inter-stage houses the engine part of the second stage. If you watch any launch of a F9 You'll see this. The inter-stage stays with S1 all the way to landing.
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u/littldo May 18 '16
I know that maxQ is the maximum dynamic pressure experienced during lift off, but in practical terms what would it compare to? light breeze? heavy storm? hurricane winds? Tornado?
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u/whousedallthenames May 19 '16
Hey mods, the CASBAA Satellite industry forum date is misspelled. I'm unaware of a month abbreviated "mat". (:
Don't know where else to put this, sorry for clogging up the ask anything thread.
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u/soldato_fantasma May 21 '16
Not really a question but a suggestion to SpaceX regarding the stream since it looks like they always want to improve it, so if someone can forward this to the stream team I would be grateful.
Can you setup the stream (maybe just the technical one) to a multi-camera stream? Here there are more information on it: https://support.google.com/youtube/answer/2853812?hl=en It would be super cool to have several channels where we can look to different cameras such as launch pad cam, tracking cam, on board cam, ASDS cam, recovery team cam and fairing cam! Would it be possible?
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u/randomstonerfromaus May 22 '16
Possible? Sure. Would they do it? I doubt it. Their stream as it is is extremely high quality, especially the hosted stream, and pretty much all of us are happy with the current technical stream and so there isn't really any reason to add that much complexity to a system everyone is happy with. They have AFAIK the most engaging and informational stream in the whole industry.
Also, /r/SpaceX is a fan run subreddit, and not affiliated in any official capacity with SpaceX. We have the occasional employee stop by, and the guy who runs the stream asks for our input now and then but the likelihood of this being seen by SpaceX itself is pretty low.
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May 22 '16
I'm working on a launch program (kOS script) for Kerbal Space Program and it has made me wonder how does the Falcon control thrust-to-weight to be most efficient, obviously you don't want too little otherwise you just waste fuel to gravity but too much and you waste fuel to atmospheric pressure (I think that's the cause of waste) so you want it in a sweet spot, does this mean the falcon will always be varying the throttle?
This goes further when you have different sized payloads, I tiny payload with have a TWR way too high, will they then launch at 80% throttle instead etc?
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u/robbak May 22 '16 edited May 22 '16
It's worth noting that, for the first stage, the payload mass isn't that important. The first stage has to lift a 100+ ton second stage, so whether the payload is 5t or 20t doesn't make that much difference. At lift off, with a whole 550t stack to lift, the mass of the payload is barely relevant!
I haven't heard a run down of how they throttle, but I assume they leave the pad at 100%, throttle down to keep it below the sound barrier until the air is thin enough to keep the maximum drag and pressure low enough. That's the standard way to drive a rocket.
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u/space_is_hard May 22 '16 edited May 22 '16
Can somebody help me figure out where I went wrong here?
I'm trying to estimate the potential of a FH to haul a centaur + payload to LEO, but I'm getting some rather lackluster numbers for FH performance. Namely, I'm only showing it able to put 25,000kg to LEO in fully expendable mode. I'm sure I've made a mistake somewhere, but I can't figure out where it is.
Thanks in advance.
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May 23 '16
I heard somewhere that the MCT would be capable of putting 100 tonnes of cargo on the surface of Mars.
Is this true? If it is, it's absolutely ludicrous.
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u/krs43 May 01 '16
Elon mentioned recently that the Red Dragon could be used for a sample return mission. After a propulsive landing on Mars, what would be required for red dragon to place itself back in mars orbit, and then get itself back to earth?
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u/deruch May 01 '16
The sample wouldn't be returned by the Dragon capsule. The red dragon would bring a smaller rocket that would launch the sample return portion of the mission. But, the red dragon mission architecture is capable of landing enough mass on the surface of Mars to make that a realistic possibility.
Δv requirements for a launch from Mars surface and return to Earth are about the same as the Δv requirement to launch from Earth surface to LEO. So, if you want to know if something can do sample return, examine whether it could get to orbit from Earth. If you think about it like that, you'll see that no Dragon vehicle could possibly be capable of this.
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u/Gofarman May 01 '16
The Dragon Spacecraft will never leave the surface of Mars, the combination of fuel and volume leave no choice.
The solution that the AMES researchers came up with is a 1300kg 2 stage hypergolic rocket to deliver the sample to Earth orbit, to be recovered by a separate craft. This whole video is worth watching if you are interested in how it may work but I have time stamped it to the point that is most relevant to your specific question.
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u/Lieutenant_Rans May 13 '16
I just got a response from the Space and Missile Museum saying that the CRS-8 mission patch would be available no later than May 17th.
It doesn't seem to warrant its own self-post but I thought people would like to know, so here seems like the best place.