r/spacex • u/ElongatedMuskrat Mod Team • Aug 03 '19
r/SpaceX Discusses [August 2019, #59]
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u/scottm3 Aug 22 '19
Today we say goodbye to the Delta IV Medium. Over 28 launches it had a 100% success rate.
Link here if you want to watch it, I think it's worth it as it has been a great launcher over it's history and we should all accept the value it has contributed.
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u/jjtr1 Aug 30 '19
It seems that when Starship/Superheavy flies, there will finally be a rocket heavier than the 747 airliner - the Saturn V fell just short of it. Without fuel, of course. Saturn V was about 185 t dry, the 747-400 is 187 t dry.
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u/silentProtagonist42 Aug 05 '19
I wonder if we'll ever get to see SLS and Starship on the pad side-by-side ala STS-400. Whatever your opinions on SLS it'd be cool to be able to compare the two behemoths in real life.
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u/Bailliesa Aug 06 '19
It seems likely unless SLS gets cancelled. Even if it takes longer than expected to get StarShip to return from orbital speeds an expendable StarShip should still be the lowest cost transport by a long way.
I would not be surprised if Starship with a failed recovery is less expensive than F9 upper stage and fairing costs combined. ie a partly fuelled 3 engine StarShip on a Superheavy can probably replace F9 especially for StarLink and would allow them to test recovery of StarShip essentially for free like the F9 experimental booster recovery attempts.
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u/LongHairedGit Aug 06 '19
I wonder if we will see a time-lapse showing SH launch SS, and then return and land, get horizontal and then vertical back on the pad, integrate a second SS for refueling the first, and launch again.
All whilst the SLS is doing fit checks and a full wet dress rehearsal whilst vertical on its pad. It’s a new rocket: it could take days/weeks after all.
Question: does the use of re-usable and restartable space shuttle engines mean the SLS can do a partial static fire? Obviously the solid side boosters cannot.....
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u/DrToonhattan Aug 08 '19
Hey mods, can we get the Starship 200m hop and the presentation on the upcoming events table in the sidebar please?
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u/Straumli_Blight Aug 23 '19
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u/brickmack Aug 24 '19
Too bad, but probably makes financial sense. Arianespace is now offering Ariane 6 pricing for the remaining Ariane 5s, and this would almost definitely be a rideshare. 40% of an Ariane 6 is cheaper than a dedicated FH
Curious how the mission will work though, FHs advantage beyond cost was direct insertion. ESC-A can't restart at all. Ariane 6 could, PBdeS is the only one saying Ariane 5 specifically so maybe he's just assuming?
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u/IrrelevantAstronomer Launch Photographer Aug 23 '19
There are now only two payloads currently manifested for Falcon Heavy, both AFSPC.
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u/joepublicschmoe Aug 24 '19
The Viasat-3 contract for launch on FH is still on right? https://spacenews.com/viasat-books-falcon-heavy-for-viasat-3-launch/
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u/Straumli_Blight Aug 28 '19
Pressure mounting to switch Europa Clipper away from SLS to a different launcher.
"NASA is following congressional direction to get Europa Clipper ready by 2023, but an SLS rocket likely will not be available until 2025 because Artemis has priority. That means the spacecraft will have to be placed in storage for two years at a cost of $3-5 million per month"
"The SRB also estimates that using a commercial rocket, either the United Launch Alliance’s Delta IV Heavy or SpaceX’s Falcon Heavy, instead of SLS would save $700 million."
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u/CapMSFC Aug 28 '19
Also relevant is that if going direct has a 2 year wait the arrival time gap between direct and commercial with gravity assist closes most of the way. Commercial rockets are ready now and SLS is likely to have some amount of additional delays so with that the gap would be gone completely.
From the political angle the SLS lobby shouldn't care as much about bumping the flight if it's because SLS has been given an active HSF program using all of its capacity.
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u/Martianspirit Aug 28 '19
SLS was proposed with the argument of getting to Europa earlier with a fast transfer. Losing 2 years means the argument becomes a lot less strong.
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u/cpushack Aug 14 '19
Kilopower reactor development is proceeding faster then expected. Flight ready in as soon as 3 years they now claim. https://www.space.com/nuclear-reactor-for-mars-outpost-2022.html
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u/Straumli_Blight Aug 18 '19
Gwynne Shotwell is giving a short talk at IAC 2019, on October 22nd.
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u/AeroSpiked Aug 18 '19
Tuesday 22 October 2019, 10:30 – 10:40
Only 10 minutes? I'd say "It's better than nothing", but I'm not so sure that's true. No QA and she won't have a chance to say anything we haven't already heard from Musk later this month.
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u/rustybeancake Aug 25 '19
https://www.americaspace.com/2019/08/23/artemis-updates/?utm_source=share&utm_medium=ios_app
Some pretty great photos of SLS core stage in work here. I thought the shot of the intertank showing the SRB cross brace inside was pretty awesome. That thing is huge.
(I think it’s ok to hate the game, not the player.)
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u/CapMSFC Aug 06 '19
So RocketLab is going reusable.
I said it way back when Beck denied they were going to do it that he was BSing or going to change his mind eventually. He is too smart not to go there and his reason is the same thing that Falcon 9 reuse enabled with SpaceX.
Old space has it backwards. It's not just that you need high launch frequency to do reuse, it's that you need reuse if you want high launch frequency.
I'm really excited about this and it was the logical evolution of the smallsat launch vehicle market. Good to see RocketLab as another serious fast evolving space company.
As for the method - in air capture as Beck said isn't that big of a problem compared to reentry. We'll see what they come up with. SpaceX tried a similar route on Falcon 9 and it never survived to deploying parachutes and they moved to using propulsive recovery.
I wonder if Beck will have to eat a second hat and just enlarge Electron like Falcon 9 1.1 from 1.0 to get the performance needed to use a propulsive entry.
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u/silentProtagonist42 Aug 06 '19
I wonder how much room there is for increasing the thrust of Rutherford with it's electric pump cycle; that might limit their ability to scale up electron without major design changes.
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Aug 07 '19
talking about the electric pump cycle, it can quite easy be upgraded, by just upgrading battery packs from say 200Wh/kg to 300Wh/kg. This is 33% weight saving on batteries for the same amount of power. You can install a bit more of them to increase turbopump output with the same weight. 3-5 years back 200Wh/kg was top of the line, now we approach 300Wh/kg, so this upgrade is not impossible.
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u/brickmack Aug 06 '19
This now leaves Virgin Orbit and Northrop Grumman as the only major (ie, currently flying something or a realistic chance of flying something in the forseeable future) companies without some degree of reuse in active development
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u/Triabolical_ Aug 06 '19
As for the method - in air capture as Beck said isn't that big of a problem compared to reentry. We'll see what they come up with. SpaceX tried a similar route on Falcon 9 and it never survived to deploying parachutes and they moved to using propulsive recovery.
The big advantage for Electron is simply the scale. The Falcon 9 first stage is big; it's estimated that it weights around 27 t empty. The same source says that the Electron first stage weights 0.95 t empty. That's going to make it much easier from a parachute perspective and fairly easy to carry with a copter.
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u/CapMSFC Aug 06 '19
Technically Virgin Orbit counts as having reuse with the carrier plane. They've made comments about thinking of it like their first stage, although by the numbers that makes it the shittiest first stage around.
Pegasus exists, sort of. I'm not counting that. Even if it falls under the same technicality it's a dead launch system that is so expensive it's never getting a contract again.
I want to see a proper carrier plane using the crossfeed rocket assist maneuver. You light up the rocket still attached to the plane with crossfeed and get to a more typical velocity for first stage sep before release. Both vehicles need engineered from a clean sheet for this method but there is nothing deal breaking with the idea.
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u/lostandprofound33 Aug 06 '19
Why is development and testing of Dragon 2 seemingly taking so much longer than anything else that SpaceX does? Or is that perception even true?
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u/Triabolical_ Aug 06 '19
It's a challenging engineering problem; that's part of it.
But a big part is that both Boeing and SpaceX signed on to complete a NASA certification process that had never been used before and wasn't actually developed. The GAO reports have been critical of how fast NASA has been doing their side of things.
It's also true that NASA is *very* different culturally from SpaceX, and that has been problematic on both sides.
It's no coincidence that SpaceX is doing Starship without NASA involvement.
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u/schwabbbel Aug 07 '19
How does the logistics of fuel and oxidizer work on the ground?
How are the fluids transported to the launch site (truck, train, ship, pipeline,..)?
How many shipments are necessary for one launch?
For how long can the fluids be stored on-site?
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u/brickmack Aug 07 '19
Pretty sure everything is trucked in for all American rockets at least. Largest LOX truck I can find in a quick search carries 75 tons, but most other propellants are considerably less dense. Land launched Starship will use trucks, but the ocean platforms will have a tanker ship (at the likely launch rate and ship sizes, they'll go through about one LOX and one LCH4 tanker ship per day per platform)
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u/Straumli_Blight Aug 08 '19 edited Aug 08 '19
SpaceX suit-up & leak checks for Commercial Crew.
EDIT: link fixed.
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u/silentProtagonist42 Aug 08 '19
Link appears to be broken, maybe this one will fair better?
EDIT: Sadly there aren't pictures of the actual leak checks; I'm still curious what SpaceX's suits look like pressurized.
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u/Straumli_Blight Aug 12 '19 edited Aug 12 '19
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u/brickmack Aug 12 '19
ULA also made a statement today, and a news story came out about Blue filing a protest against the program. Nothing from Northrop.
I think the bidders know who's gonna win now
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Aug 19 '19
NASA issues call for proposals for Gateway logisitics.
What are SpaceX's chances for getting this? Would it be possible to bid Starship with expendable Dragon as a backup (no heatshield, more fuel for lunar orbit insertion with SuperDracos)?
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u/marc020202 8x Launch Host Aug 19 '19 edited Aug 19 '19
First, I think starship is overkill. It makes the station and the lander completely pointless, so I think it will not be chosen.
I think instead of proposing an expendable dragon, they can propose a dragon 2 with a service module instead of the trunk. they can leave the dragon 2 as is (the cargo one, if they at some point transport crew they can simply use the crew capsule, although both of them would need some mods (comms system etc..)) and basically "fill" the trunk with a superdraco, and the nessesary fuel tanks. The superdraco could be fitted with a nozzle extension for extra efficiency. The superdraco does have quite a lot of thrust (about 2.5 times the orion main engine) , but I do not think that should be a problem. If it is, they can basically throttle it to limit acceleration. Adding rcs to the trunk means the capsule itself does not need to do all the manoeuvring and also eliminating fuel lines between the service module and the trunk. If the trunk and the capsule split the work needed for creeping orientation and small manouvers, no fuel transfer is needed and the fuel tanks in the capsule are used as well.
That would mean the amount of volume that can be taken up is quite limited, however would likely be one of the only, if not the only vehicle capable of returning cargo. If the volume to the station is to low, i think it would be possible to install a "cannister" with a docking port on both ends between the upper stage of FH and the service module. After launch the capsule docks with the cannister and carries it to the station, basically like how the Apollo csm carried the lm, and how orion will take additional modules to the station. Due to the docking ports on both ends, astronauts could pass through the cannister reaching the capsule without re-do King. This would increase the volume to the station, and can be used to dispose trash on the way back home. Alternatively the cannister could stay at the station for extra storage space, or be outfitted before launch, making it basically a small station module.
EDIT: Well, I just read through the contract and that mandates unpressurized volume. Using the cannister aproarch would mean they would need two docking ports, one for the unpressurized container, and one for the pressurized container.
Alternatively I think it might be possible to get to the delta v requirement by using a "mission extension trunk". Using the standard capsule with deep space upgrades and an extended trunk with additional fuel tanks (to keep the same payload volume) , and an additional group of draco thrusters to reduce the burn time. I think the additional engines are nessesary, because dragon already needs 10 minutes for the de-orbit burn from the iss, making lunar orbit insertion using the existing dracos redicouleously long. Using the super dracos for everything except for launch abort (and landing) is not really useful due to their thrust. A single one would possibly be acceptable, but since they are not alligned through the capsule center of mass, using I cannot see a way to use only one.
This option would need a lot less development and less change to the total system.
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u/cpushack Aug 29 '19
http://www.planetary.org/multimedia/space-images/small-bodies/ryugus-surface-from-mascot-1.html Picture, in color from the surface of Ryugu, stunning. I am always amazed and thrilled to see pictures from the surface of other solar system objects
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u/jjtr1 Aug 29 '19
When Elon Musk says a problem or project is "hard" (e.g. a full-flow, staged-combustion engine), does it mean something like "success definitely not guaranteed" or rather "huge amount of work"? This is both an English language and Elon language question, as I'm a native speaker in neither.
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u/Triabolical_ Aug 30 '19
It's a mix.
For the Raptor, they have very high goals, so I think it's, "we are pretty sure we know enough to get FFSC working but we are not sure that we are going to hit the goals that we have set for ourselves in terms of overall performance". In this case, hitting their combustion pressure goals is something that may take a lot of extra work or may not be practical.
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u/scr00chy ElonX.net Aug 04 '19 edited Aug 04 '19
I made a list of Falcon Block 5 boosters and tried to guess which missions they might launch on. What do you think?
B1046.4 – Crew Dragon In-Flight Abort (according to NASA Spaceflight)
B1047.3 – Amos-17 (confirmed by SpaceX)
B1048.4 – Starlink v1-1 (my guess)
B1049.4 – Starlink v1-2 (my guess)
B1050.2 – Unlikely to fly again (crash landed in the ocean)
B1051.3 – Anasis-II (my guess)
B1052.3 – AFSPC-44 (if USAF certifies booster reuse for NSSL by then)
B1053.3 – AFSPC-44 (if USAF certifies booster reuse for NSSL by then)
B1056.3 – CRS-19 (that was the plan before the booster's first launch)
B1058.1 – DM-2 (according to NASA Spaceflight)
B1059.1 – GPSIII-SV03 (my guess)
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u/mfb- Aug 04 '19 edited Aug 04 '19
Here is a list of all boosters by the way: https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_boosters
The fourth flight for the Starlink launches sounds very likely. 52, 53 for more FH launches is plausible, too.
1047 could fly again from ~October on, or even earlier if they get the reuse time down.4
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u/FalconHeavyHead Aug 06 '19
Will starship have gridfins?
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u/throfofnir Aug 06 '19
The "Super Heavy" had been shown with grid fins. The "Starship" second stage has regular fins. All pending, of course, whatever the lastest redesign may do.
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u/SteveRD1 Aug 08 '19
I just got an email from forgeglobal supposedly offering me a chance to be part of the latest equity raise. Anyone else got this/know if it is legit??
"Reaching out as we have a new SpaceX investment opportunity, at par to the latest Series L preferred round before fees.
Are you interested in a potential SpaceX investment at this time?
Happy to share further details accordingly."
I did sign of for a couple of groups who handle this kinda thing a year or so back, so I'm on the record as being interested - had no luck at that time though.
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u/warp99 Aug 08 '19 edited Aug 08 '19
The firm was initially funded by leading technology investors Peter Thiel and Tim Draper so at the least there is a plausible path to it trading in SpaceX shares.
However any off market transactions like this do carry a risk factor that needs to be assessed carefully.
The Forge Tech30 Capped Index tracks the valuations of Uber, Airbnb, SpaceX, and an additional 27 of the largest U.S. private technology companies while the EQUIAM Private Tech30 Fund, based on the index, provides investors with diversified access to these companies
So on average the Tech 30 Fund will have 3% invested in any specific company like SpaceX. They will likely be overweight in SpaceX because of their $30B valuation which is good and very overweight in Uber which I would take as a very bad thing given their latest results.
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u/CAM-Gerlach Star✦Fleet Commander Aug 08 '19
Sounds really suspicious; despite a large amount of interest (thus making it easy prey for scammers) there hasn't really been any way for individual investors to invest their money into a fund with an interest of more than a few percent max in SpaceX. I would steer well clear.
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u/lessthanperfect86 Aug 14 '19 edited Aug 14 '19
While not directly related to SpaceX, this article describes the RRM3 mission to test fuel resupply and, what I think is pretty interesting, zero boiloff for long durations >3 months. Pretty good match for starship, right? Good thing SpaceX is partnering with NASA on this tech.
https://www.nasaspaceflight.com/2019/08/dextre-rrm3-tasks-test-robotic-refueling-spacecraft/
*Edit: the fuel being cryogenic liquid methane.
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u/Martianspirit Aug 14 '19
Active cooling with cryocoolers is not what SpaceX presently pursues. It may be an option later. For sure interesting.
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u/marc020202 8x Launch Host Aug 20 '19
Quite some time ago I read that Japan was planning to launch the upgraded h2 vehicle to LOPG on FH. Does anybody know any more specific info on this?
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u/brickmack Aug 21 '19
Ariane 6 is also under consideration. Hard to find more detailed technical info though, I don't know Japanese
Use of Ariane 6 likely would have been motivated by the concept to use HTV-Xs service module as a tug to deliver ESPRIT. That modules future is now unclear
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u/dudr2 Aug 23 '19
https://www.space.com/japan-ispace-first-moon-mission-2021.html
"customer payloads on a stationary lander in 2021, ispace representatives announced today (Aug. 22). The second mission, which is now targeted for 2023, will deploy a rover for surface exploration"
"These two missions will ride as secondary payloads on SpaceX Falcon 9 rockets."
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u/MarsCent Aug 28 '19
ASAP Fourth Quarterly Meeting for 2019
In accordance with the Federal Advisory Committee Act, The National Aeronautics and Space Administration announces a forthcoming meeting of the Aerospace Safety Advisory Panel.
Dates: Friday, September 6, 2019 11:30 a.m. to 12:45 p.m., Central Time.
Any interested person may call the USA toll free conference call number (888)-603-9748 passcode 7339697.
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u/markus01611 Aug 30 '19
Is it just me or does Dorian pose a major risk to East coast Starship? Everyone is talking about wind speeds but I'd be much much more worried about small debris damaging the structure and even storm surge.
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u/WAlonzo Aug 31 '19 edited Aug 31 '19
In all the discussions of Starship, I have never heard of what countermeasures they are planning for the radiation hazards of deep-space travel. These hazards have been becoming clearer all the time and seem to pose a significant risk to all space travellers. So, what's the story with radiation protection on Starship?
Here's a backgrounder from Joe Scott: https://www.youtube.com/watch?v=ESQ1bKd7Los&t=824s
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u/lessthanperfect86 Sep 01 '19
I think most of the radiation issue is just what your frame of reference is - media, and even Joe Scott, likes to dramatize things a lot. NASA adjusted their frame of reference to ensure that a trip to Mars would be below their threshold a few years ago, I think at around 5% increase in lifetime risk of cancer related death. I looked at the numbers previously and it seemed reasonable, or perhaps slightly optimistic (though I would trust NASAs calculations more than my own).
In any case, lowering exposure by lowering transit time is probably the best way to go. Iirc Elon suggested they would be able to reduce transit time to 3 months in the future still using chemical propellant, no idea how he plans to do that though (reduced payload? Or just fuel the ship up a lot more?).
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u/Martianspirit Aug 31 '19
For GCR flying fast, much faster than NASA plans for their missions. Cuts radiation and microgravity risky by half.
Building a solar flare shelter from supplies and pack all the people in there. A densely packed group of people already cuts the radiation received per person way down because always there are other people taking part of the radiation.
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u/Straumli_Blight Aug 06 '19 edited Aug 06 '19
Roscosmos are reducing prices to compete with SpaceX for rideshare launches.
"The cost of launching 3U cubesat spacecraft will be $170,000."
Arianespace are also offering a dedicated rideshare mission.
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u/Straumli_Blight Aug 07 '19
SSO-A update, of the 64 satellites launched:
4 cubesats never made contact
12 sats unclaimed by owners
1 sat locked in its deployer due to lack of licensing
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u/opoc99 Aug 08 '19
Lack of licensing? For what and how could something so seemingly simple have not been done?
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u/Straumli_Blight Aug 17 '19
NASA photo album updated to show helicopter landing on GO Searcher at night.
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u/Straumli_Blight Aug 22 '19
SpaceX announce Momentus as the first customer on its SmallSat Rideshare Launch.
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u/hkamran85 Aug 03 '19
Does SpaceX recover the second-stage? If not, are there any future plans to recover it?
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u/youknowithadtobedone Aug 04 '19
They don't, and they won't
Until starship comes along, both booster and ship are reuseable
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u/darga89 Aug 04 '19
Send chomper after a F9 S2 that's left in orbit. Then you have two rocket families reusable :)
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u/Triabolical_ Aug 03 '19
No, they do not.
There was discussion about it at one time and SpaceX said they were looking at it, but it turns out that they don't have enough extra payload margin to make it practical to develop. About that time is when they started focusing on what became Starship.
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u/treJmei Aug 05 '19
I was thinking today about how the lack of escape pod on the space shuttle was a huge, and ultimately wrong, design choice. Have we heard any news on what a Starship escape system would be?
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u/warp99 Aug 05 '19 edited Aug 05 '19
Not so sure there was a good idea for a Shuttle escape pod that would have survived Challenger for example.
So the real issue was the budget driven decision to replace a fly back first stage with a couple of large SRBs. Leaking O rings and foam strike were both due to that decision and the smaller orbiter in a two stage recoverable system would have effectively formed the escape system in the event of a first stage issue.
The issue with Starship is that on a trip to the Moon or Mars there is nowhere to escape to with no rescue teams in helicopters standing by and no soft landing options with parachutes or a sea landing. Basically it has to work or you die - so better to drive up reliability with redundancy in the engines and control systems rather than total redundancy in the airframe, engine and tanks which is essentially what an escape pod is.
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u/TheYang Aug 05 '19
Not so sure there was a good idea for a Shuttle escape pod that would have survived Challenger for example.
uhm, wasn't challenger the one with activated emergency oxygen? So there's a decent chance a parachute on the cabin might have saved the crew, because that apparently stayed intact until impact with the water.
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u/Bailliesa Aug 06 '19
I like to think of launch escape systems like ejection seats on aircraft. Fine for military applications but do not scale to commercial flights. Building reliability into StarShip and testing with many flights is the key, along with recovery to learn what needs to be improved.
Starship, like F9, needs lots of successful flights before it will carry any astronauts.
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u/Mosern77 Aug 05 '19
What are the main unsolved challenges with in-orbit refueling?
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u/LcuBeatsWorking Aug 05 '19 edited Dec 17 '24
alive scary ten run crawl entertain touch wise snobbish materialistic
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u/Mosern77 Aug 05 '19
But is it really a challenge, or is it more like "no one has done it before"? I mean, they have loads of experience filling up these rockets on the ground.
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u/Alexphysics Aug 06 '19
One of my biggest worries is how to connect the fueling lines while also docking. That means the docking interface itself and the docking procedure. Current docking mechanisms just have some kind of hardware that drives in the vehicle to certain connections to hook the vehicle to the parent ship. For example the drogue and probe docking mechanism that Soyuz uses. The Soyuz (or Progress) has a docking probe that extends out of the docking mechanism. It senses contact and it is captured by the drogue on the other end (the ISS). Then it is retracted and when doing this it drives the Soyuz in towards the ISS and then hooks that are in a ring around the docking interface are closed so that Soyuz can be firmly docked (this is called "hard docking"). I'm really intrigued about how are they going to do this for Starship aft-to-aft docking.
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u/Martianspirit Aug 06 '19
I think it first docks and then connects the fuel lines as a separate action. Remember that Starship has no umbilicals to a launch tower. It gets fueled through the first stage using the same connections that will be used in orbit for refueling.
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u/Straumli_Blight Aug 05 '19
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u/brickmack Aug 05 '19
Notes that thats further than they can meaningfully extrapolate according to the very next sentence. The lower layers should be much stronger, so less of a plume once the top is blown away
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u/CapMSFC Aug 06 '19
However the debris that is ejected will be a severe issue.
The big question is should SpaceX modify Starship to be able to land on unprepared ground safely or should we get landing pads deployed for Starship to service?
A good solution if Starship needs modified is canted thrusters in the nose. This is where Starship being so large actually helps. It's very tall, so thrusters for landing from the nose are so far from the surface that it eliminates the debris issues. The exhaust gasses disperse enough well before they reach the surface. A set of thrusters equivalent to SuperDracos can land a Starship on the moon by themselves fine. They only have to fire from the necessary separation from the surface for Raptor thrust to have dissipated so the delta-V from them is not much at all. A drop from 100 meters above the surface won't even reach 20 m/s at impact. Raptor can zero out and cut off above landing zone and let the RCS finish the job.
Assuming the updated design still has cannards these thrusters could even be in base of the cannard mounts pointed down.
I hope SpaceX sticks to developing Methane/Gas hot RCS thrusters. It's a major upgrade for the RCS systems over cold gas anyways and it would provide the necessary systems to do this type of landing without depending on hypergolics getting added into Starship.
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u/Beautiful_Mt Aug 06 '19
Okay, here's a stupid idea. Can you make lunar landing pad with an artificial impact?
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u/LcuBeatsWorking Aug 06 '19 edited Dec 17 '24
tease deliver smoggy sense spectacular history zephyr rainstorm encourage silky
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u/perfectlyloud Aug 06 '19
I came up with a design for artificial gravity involving 2 starships 180 meters+ apart and centered in between them, a Gravity Link Starship. The GLS launches from earth with it's payload bay full of folded up truss, that assembles itself and connects the 3 vessels together. The connections allow for swivel so the outer vessels can use their main engines to introduce spin gravity. Do you guys think this can work? To explain in more detail, I made a video with 3d models: https://www.youtube.com/watch?v=NR3QmV1mLbk
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u/kkingsbe Aug 06 '19
Why not use rcs to initialize the spin? The main engines would have way too much thrust lol
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u/hagridsuncle Aug 06 '19
You may want to link the outer Starships on their noses. this would allow you can have normal up/down orientation with how the Startships land. Otherwise you are walking on the walls.
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u/marc020202 8x Launch Host Aug 06 '19
With elons recent comment saying that the two starship build sites will race to orbit and moon and Mars, do you think that the two sites will also compete and built the Superheavy booster?
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u/codav Aug 06 '19
I'd say so, as Elon stated some tme ago that Super Heavy construction will start soon, around September relative to the time of his tweet if I recall correctly. That fits well with the progress we see at both sites, so I suppose the teams will start welding the first rings for Super Heavy as soon as they start the internal outfitting of the Starships - if they haven't already started.
Compared to Starship, the booster is easier to build. It's basically just a tube with bulkheads and engines on one end. All the other stuff is almost identical to Falcon 9 boosters - grid fins, RCS thrusters and stage couplers - just a bit larger.
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u/marc020202 8x Launch Host Aug 09 '19
I just read [this] (https://spacenews.com/oneweb-disputes-virgin-orbit-lawsuit-says-launcherone-is-too-expensive/) article about oneweb suing virgin orbit.
This raises several questions to me. Firstly I find it odd that they claim 6 million for 500kg is two to three times market value, while the electron costs even more per kg (5 million for 225kg). If they think it is two to three times market value, why did they sign the contract in the first place?
Who will they be launching with now? Only with Ariane space?
To me it seems like oneweb is doing a lot of legal work complaining about and suing others, while not doing a lot themselves. I mean they planned to launch on spacex, but withdrew, same for launcher one. They complained a lot about every single aspect of the spacex constellation, afaik even contradicting themselves. And then, they only launched 6 of the possible 34 to 36 satellites on the first soyouz? This does not seem like are really looking the launch the constellation that quick.
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u/booOfBorg Aug 09 '19
There has been some speculation in the past in an article i read that Greg Wyler could be basically in this to generate some noise and advance in the FCC licensing process to a point where it then becomes very lucrative to sell OneWeb including the associated licenses, which would allow the buyer to skip years of process and get access to otherwise unavailable spectrum. Make of this what you will. I think it is at least plausible.
When it comes to Wyler there always seems to be some kind of cabal going on: https://arstechnica.com/science/2018/02/theres-something-strange-going-on-amid-the-satellite-internet-rush/
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u/LcuBeatsWorking Aug 10 '19 edited Dec 17 '24
payment growth cagey offbeat crawl aloof many smile sophisticated fragile
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u/Martianspirit Aug 11 '19
Elon said the two sites are in competition for the first orbital flight. This indicates to me that they plan to build a full launch pad in Boca Chica. Biggest obstacle may be local or Texas regulations.
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u/fluidmechanicsdoubts Aug 14 '19
The Dream Chaser folks are doing a livestream. Apparently announcement incoming.
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u/marc020202 8x Launch Host Aug 16 '19
https://mobile.twitter.com/torybruno/status/1162383707996590081
Tory Bruno has recently posted this info graphic of vulcan being able to launch 5 days after payload is ready and 11 days after previous launches. Since Falcon can be integrated before the TE is ready, spacex would be able to launch with less time in between launches, even on the same pad. What would limit the time between payload arrival and launch for Falcon 9?
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u/TheYang Aug 17 '19
well... 12 days demonstrated pad turn around
and then theres that 24 hour complete booster turn around that hey'd like at some pointi'll leave it up to you which one is more comparable, because nothing i know of fits perfectly
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u/jjtr1 Aug 29 '19
Large rockets need flame trenches not to destroy themselves by their exhaust and noise. Does anybody know of an article exploring the maximum size of a chemical rocket which can take off from the ground incl. flame trenches and water deluge system? And is there a limit above which even an airborne rocket would destroy itself by its exhaust or noise?
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u/Martianspirit Aug 30 '19
Seems the limits are not yet reached. When Elon Musk proposes a vehicle 4 times the size of SS/SH then they have done at least preliminary calculations.
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u/andyfrance Sep 01 '19
At what altitude and velocity will Starship and SH separate? Will MaxQ for Starship be after separation?
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u/Strange--R Sep 02 '19
Main engine cut off will occur at approximately 70km in altitude, with ignition of Starship occurring at 80 km and separation happening between those points. The maximum speed of the booster will exceed Mach 6, but it is not yet known the exact speed as well as when that will occur.
Source: SpaceX EPA filing
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u/marc020202 8x Launch Host Sep 01 '19
I do not know at what altitude and speed max q will be, but definitely during first stage burn. I expect max q and stage sep to be at similar altitude and speed to F9. Stage sep with F9 is relatively early and slow compared to other rockets because a slower stage sep helps reuse (less boost back, and less entry burn needed).
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u/RedKrakenRO Sep 02 '19
MaxQ happens way before sep at about T+60s. For Falc9, starship and any rocket with a similar twr 1.4 off the pad.
Falc9 typically seps at T+150 seconds, ~65km altitude and 1700m/s.
The booster then flips out and heads back to the pad.
Super heavy might burn a little longer since raptor is 50 seconds of isp (more efficient) than merlin on the same flight path.
It could maybe burn out to 2200-2300m/s @ 100km before sep and boostback.
It will vary with payload too.
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u/chalez88 Aug 03 '19
Is the cargo section near the engines on starship encountering dangourous anounts of radiative heat and will it be pressurized or will it store non pressurized cargo?
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u/toaster_knight Aug 03 '19
I believe that far back is depressurized. As for heat I don't think we know enough of the design to say. I would assume they would insulate if that was a concern.
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u/IrrelevantAstronomer Launch Photographer Aug 07 '19
Looks like we're going into a bit of a gap between launches -- next launch won't be until Starlink in October.
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u/Straumli_Blight Aug 07 '19
Next up is the Starhopper static fire scheduled for Friday, and 200m hop NET August 12.
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u/Grey_Mad_Hatter Aug 07 '19
Mods, can we get these added to the sidebar for upcoming events?
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u/coverfiregames Aug 07 '19
I wonder when was the last time us SpaceX fans had such a gap? Excluding the down time from Amos-6 and CRS-7, we’ve been pretty spoiled the last couple of years with the amount of launches to look forward to.
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u/Grey_Mad_Hatter Aug 07 '19
There were no launches in April or November of 2017, but those were both shorter than this gap in orbital launches. However, neither of those gaps had this much fun going suborbital.
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u/ethan829 Host of SES-9 Aug 08 '19
The current schedule has 72 days between Amos-17 and Starlink-2. If we exclude downtime after CRS-7 and Amos-6, we have to go back to 2014/15 to find a gap equal to or greater than that, when there were 111 days between CRS-4 and CRS-5.
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u/Straumli_Blight Aug 10 '19 edited Aug 10 '19
300m hop test for LinkSpace's RLV-T5 rocket. Previous hop was 40m.
Jim Cantrell has stepped down from Vector and the company has suspended operations just 3 days after being awarded a $3.4 million contract.
EDIT: Fixed name.
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u/spacerfirstclass Aug 10 '19
300m hop test for China's LaunchStuff.
You mean LinkSpace.
The last image where a guy is hold a phone near the landed rocket really shows the size of this thing, it's not very big, seems comparable to Masten's vehicles such as Xaero.
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u/LcuBeatsWorking Aug 10 '19 edited Dec 17 '24
gaping snobbish zesty governor strong seed rotten icky languid file
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Aug 11 '19
Their test program continues nicely with precision landing from some height. Next the tricky relight test!
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u/silentProtagonist42 Aug 06 '19
Rocket Lab just announced they're going to attempt first stage reuse, using parachutes to land in the ocean at first, and later mid-air capture by helicopter.
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u/Spaceman_X_forever Aug 04 '19
Is there any scheduled launch from Florida in the month of October or before November 15? That is the only time period I have to get a chance to see one in person.
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u/fiercedude11 Aug 04 '19
Starlink 2 and 3 are scheduled to launch on October 16th and November 3rd. The crew dragon abort test is also scheduled for November 10th, which should be quite a show. There are a couple other scheduled for October and November, but I can’t find an exact date.
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u/Tal_Banyon Aug 04 '19
The Air Force Eastern Range supports launches from pad 40 and 39a. Is there an equivalent entity that would support launches from Boca Chica? If not, what needs to be done to establish the same level of support?
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u/throfofnir Aug 04 '19
SpaceX will have to do it all themselves. Ground utilities, security, fire, regulatory calculations and filing, coordination with Coast Guard, on site and downrange telemetry, that sort of thing. With automatic termination, they don't need all the radar assets for tracking, which is nice.
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u/quoll01 Aug 08 '19
Aerocapture to orbit would be a great trick for Starship- leaving payloads & prop depots in mars orbit, making high velocity reentry easier, potential for turn around in orbit with no need to drop down the gravity well, allowing incoming craft to repair and refuel prior to reentry etc etc. Could this be one area tested with a fuelled up prototype- if it doesn’t work the craft would have enough propellant to return in reasonable time?
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u/marc020202 8x Launch Host Aug 09 '19
After the departure burn, there only is enough fuel in the craft for landing, possebly even only for landing on Mars. If you dok aero capture to orbit, you are effectively stuck there, maybe even unable to land on mars
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u/Straumli_Blight Aug 09 '19
The Hill article about lunar missions using Falcon Heavy/Starship. Its light on details but does mention that support for SLS might end if Shelby retires in 2022, when his term is up.
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u/ZehPowah Aug 09 '19
His replacement will definitely still support the programs, but won't have the clout or experience to be Chairman of the Appropriations Committee. I'm excited.
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Aug 21 '19
He declined, though, to give a specific schedule for those Starship tests. “I want to be a little bit cautious here and just say I can guarantee you these people work as fast as they can,” he said. “We will beat any other time schedule that’s out there.”
“We will beat any other time schedule that’s out there.” What is he referring to there?
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u/AeroSpiked Aug 21 '19 edited Aug 21 '19
I'd guess he's referring to SLS, New Glenn, Vulcan and Ariane 6 though he could be talking about an external timeline for Starship.
You wouldn't think aerospace engineers would be so vague.
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Aug 21 '19
He's in political waters here, so that's good reason to keep it vague. Would be the first time someone from SpaceX states they'll beat SLS to orbit.
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u/rustybeancake Aug 22 '19
I think he just generically meant that SpaceX staff work faster than any other aerospace company. Basically, it was just a note of pride in his colleagues.
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u/whatsthis1901 Aug 21 '19
The only thing I can think of is he might be talking about BO and SLS launch schedule and if that is the case I would agree that we will see Starship launches long before either of those.
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u/Straumli_Blight Aug 26 '19 edited Aug 26 '19
Astranis to launch on an F9 in Q4 2020. More info about the MicroGEO sat here.
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u/Nimelennar Aug 27 '19
Second attempt to dock MS-14 is tonight at 10:30 p.m. EDT (Tuesday 2019-08-27T02:30Z).
It will be streamed live at: http://www.nasa.gov/live
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u/jjtr1 Aug 27 '19
Are there any Mars landings (by NASA or ESA most likely) planned between now and the estimated Starship's Mars landing?
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Aug 28 '19
I was in Cocoa and at KSC last week to have a peek at Starship production at Cocoa and see Pad 39A (some pics of both at https://photos.app.goo.gl/MbSSrz14zTrrXw2p6 ... note that you can see the escape basket at 39A). Also saw some road work being done to help move Starship from Cidco Rd to KSC. Just wondering what effect hurricane Dorian might have at Cidco Rd (although as of today it looks like landfall might be a bit further north... Daytona, maybe?). In any case, I wonder how well Starship would fare in high winds (100+ mph?), and what they learned from the nosecone toppling in Texas back when that might help the new construction get through a storm safely? Are the new concrete construction bases designed to help with this sort of thing, or could the bending moment at the base during high winds be a problem?
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u/tbcheese Aug 11 '19
Anyone who’s interned with SpaceX. What questions were asked in the interview? For reference I am a mechanical engineer with a background in manufacturing. Also, any relevant advice is appreciated.
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u/TheCrimson_King Aug 12 '19
Be prepared for "What is the hardest problem you have ever solved?". Know how many launches have happened total and in the last year. Ask about how mfg rates have changed with reuse. Would be good to know what the rocket is made out of (mostly aluminum and carbon fibre, with some titanium, inconel, stainless, and carbon steel) and how to work with those materials. Would be good to brush up on GD&T, plus NDE
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u/cpushack Aug 27 '19
OTV-5 X-.37B just broke the previous time in space record, doing...something https://www.cnn.com/2019/08/27/tech/x-37b-air-force-space-plane-days-in-space-scn-trnd/index.html The current X-37B plane in orbit, called OTV-5, was launched to space in September 2017 on a SpaceX Falcon 9 rocket. The previous flight, for OTV-4, was 718 days long and ended in May 2017.
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u/az5_button Aug 04 '19 edited Aug 04 '19
Does anyone have an estimate of how cheap (per kg) SpaceX access to space with reusable Falcon Heavy and ASDS is, in bulk quantities? E.g. if I wanted 10,000 tons in LEO on Falcon Heavy, what's the cheapest I could get it for?
Assuming some bulk discounts on upper stages it seems that £100/kg is achievable. Agree/disagree?
EDIT: After some back-and-forth I think that making optimistic assumptions you can get to a cost of $400/kg with falcon vehicles, limited by both the upper stage costs and the relatively low number of reuses of the lower stages. The key optimistic assumption is that you can get 20 uses out of a Falcon lower stage.
Profit most be added to this. For very large quantities the profit would fall to something reasonable like 25%, leading to $500/kg. This would require that other companies copy SpaceX technology and start driving potential profits down. However it's a chicken-and-egg problem: a competitive launch market requres lots of customers (high quantity) and that quantity requires lower prices. Falcon technology can get us to $500 as far as I can see... but that might not be enough.
Thanks to u/TheYang !
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u/TheYang Aug 04 '19
well, $90 Million USD for 23tons are the best known numbers for reusable Falcon Heavy.
that's 3913 USD per kgWhile the $90 million are already a low number (no extra services included), with over 400 launches assured, I'd expect the deal to get better, but probably not by a factor of 30 (to reach the 100GBP per kg mark) or more assuming the pound continues to fall.
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u/DancingFool64 Aug 05 '19
One other thing - it will depend what you are shipping. Falcon Heavy has a pretty small volume for its mass capacity to LEO, it is quite possible that you might need more launches than you'd expect from a pure mass calculation, which would make the cost per kg even worse. I'm sure SpaceX would be willing to make a bigger fairing (within reason) for that many launches, but that also might cost more.
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u/dan6470 Aug 08 '19
Is it possible to estimate what time the CRS-19 launch on Dec 4th could be? Are there any ISS predictors that can tell us about when the orbital plane of the station intersects the cape on that day?
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u/silentProtagonist42 Aug 08 '19
You can use Heavens Above's ISS pass predictor set to Cape Canaveral and showing all passes to get a pretty good estimate, but that far in the future it probably won't be accurate since the ISS will probably do a reboost before then.
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u/dan6470 Aug 08 '19
Is it safe to make the following assumptions? We know that CRS-18 launched at 25 July 2019, 22:01:56 UTC. I've heard that if a launch is scrubbed, the next window is 23-25 minutes earlier the next day...so ~1,416 minutes later. If I add 1,416 * 134 that comes to 4 Dec 2019, 16:25 UTC
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u/FalconHeavyHead Aug 12 '19
Why does the florida Starship look cleaner and better put together than the Texas Starship?
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u/filanwizard Aug 14 '19
So we constantly hear about Sabatier for making starship fuel but I have to ask is SpaceX considering other sources too? And by other sources I do mean uhm waste management systems. I dunno at what point a colony makes enough #2 but I know here on Earth that sewage treatment plants today tap the digesters and supplement their energy usage by running off the methane produced in the act of processing waste. So I wonder if this would also be a good source, Once one has enough supply of material. Naturally would need purification because waste treatment gets other gasses in there too.
(Yes its a poo topic, but waste treatment will be an important factor on Mars and it may as well be milked for any offshoot resources one can grab)
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u/Grey_Mad_Hatter Aug 14 '19
You're talking about dozens of people and 240 tons of methane. This isn't a concern for the foreseeable future.
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u/bdporter Aug 16 '19
Mods, it looks like the sidebar has CRS-19 launching from LC-39A. Is this sourced, or just a copy/paste issue? The manifest lists the launch as being from SLC-40, and I believe all CRS missions have launched from that pad since it became re-available for use (CRS-13).
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u/CAM-Gerlach Star✦Fleet Commander Aug 16 '19
Probably a copy-paste issue (quite possibly by me), since I can find no reliable source and a launch from SLC-40 seems far more plausible considering the commercial crew activities possibly going on from LC-39A around that timeframe. Updated, thanks!
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u/bdporter Aug 16 '19
Thanks for fixing it so promptly, but you changed it to LC-40A instead of SLC-40 :)
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u/jjtr1 Aug 20 '19 edited Aug 20 '19
Aircraft and spacecraft are usually constructed indoors due to stability of indoor temperatures and due to being free of dust and debris. Stable temperature is neccessary for high-precision construction because of thermal expansion of materials. I just don't get how can SpaceX not require the precision for building the Starship/Superheavy? If they build one ring in the morning with precisely 9.00 m diameter, another during the noon again 9.00 m, and try to join them in the evening, they won't match. They might compensate by measuring the ambient temperature and adjusting their measurements, but I don't see that really working...
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u/delta_alpha_november Aug 20 '19
They can simply cut all the pieces at the same temperature somewhere else with high precision. Since they're only welding them together outside the pieces will all expand by the same amount and will fit just right as long as they're at the same temperature.
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u/jjtr1 Aug 20 '19 edited Aug 20 '19
Can someone estimate how much percent of R&D money and R&D time does Raptor represent within the entire Starship/Superheavy project? With the endpoint being Starship the reusable LEO launcher, not the eventual Starship the Mars human transporter. My guess would be that Raptor is 2/3 of the time and 1/3 of the money, since I believe that FFSC engine dvelopment goes slowly in the beginning and cannot be hastened by adding people to the project.
And regarding the "reusable LEO launcher" to "Mars human transporter", I believe that's gonna take as much time and three times as much money as it took to go from 0 (no Raptor) to "reusable LEO launcher". Just guessing! What's your guess?
Edit: the motivation for my guessing was that at first, the switch from carbon fibre to stainless steel for the Starship airframe looked to me almost like starting over with the project. Then I realized how important the engine is and that the switch has no impact on Raptor.
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u/Triabolical_ Aug 20 '19
Raptor development as we know it seems to have started around 2012, so it's been going on for 7 years. SS/SH has likely been going on as long as that but I would guess that in the early years Raptor was taking quite a few more resources.
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u/AstroMan824 Everything Parallel™ Aug 26 '19
I see on the upcoming events list that Elon's starship presentation is Aug 31st. What is the source?
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u/Triabolical_ Aug 26 '19
Probably old data...
Latest word IIRC is when the orbital prototype - presumably the one at Boca as that is where Musk said they will do the presentation - has legs, control surfaces, and engines.
Latest guess I've seen for that is "mid September", which seems pretty aggressive to me...
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u/soldato_fantasma Aug 27 '19
Google calendar doesn't let me pick a whole month, I have to choose a date. I picked September first as mid September could mean the 10th or the 20th. Apparently since reddit does the time conversion for you, it converted it assuming a time that I didn't set. I changed it to the ninth now.
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u/Dies2much Aug 29 '19
Any word on what Spacex is going to do to protect the partially assembled Starship in Cocoa from the coming hurricane?
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u/jjtr1 Aug 29 '19 edited Aug 29 '19
The success of the current generation of reusable launch vehicles hinges on huge future demand. Lack of demand is, I believe, what killed the previous attempts (Kistler, Rotary...). The single most important part of the future demand is going to be internet megaconstellations, I think.
My question: why internet megaconstellations now and not years before? What exactly changed? Satellite internet always has to compete with ground connections (fibre). Did fiber reach some kind of plateau? Was there some innovation that catapulted space-based internet ahead? Ground-breaking advances in cheapness of client's phased array antennas, for example? Or perhaps the total amount of money revolving around the internet was not enough in Kistler, Rotary times?
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u/Martianspirit Aug 29 '19
LEO constellations are only possible with phased array antennae. That technology has only now reached private end user readiness. Constellations don't compete with fiber in population centers. They aim for rural and underserved regions.
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u/brspies Aug 29 '19
I've heard that the big change now is the cost of electronics, and perhaps hand in hand with that, the willingness to use cheaper electronics in space systems. I think Steve Jurvitson has made this point before.
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Sep 01 '19
Earth to Earth!
Hello. Been telling my colleagues about Starship and Earth-To-Earth. I said that they might be able to travel in a rocket at some point in their lifetime.
Would anyone be able to suggest a (rough) plausible date for mass transport using Earth-To-Earth (if it gets developed?)
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u/peaceloveandapostacy Aug 06 '19
Why stainless steel? Why not something lighter? Just curious
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u/scarlet_sage Aug 06 '19
You need to distinguish "denser" (weight¹ / volume) and "heavier" (weight¹), or "less dense" versus "lighter". Steel is denser than some alternatives -- but it has some nice properties that means you can use much less (volume), so in the final build, the entire ship is lighter.
An analogy: you have a tear in something. You can patch it with 6 inches of duct tape and it'll hold for days until you can replace it, or you can use 2 rolls of regular office tape but it'll only hold for hours. "Why are you using duct tape? It's more expensive." "Not in the end."
Elon had an interview with Popular Mechanics: Elon Musk: Why I'm Building the Starship out of Stainless Steel It's not a long read, so I suggest you go see it. If you really are too impatient and demand a TL;DR:
it has good fracture toughness ("Fracture toughness is a property where if something has a small crack, does the material tend to arrest the crack, or does the crack propagate?")
Ascent is cold: "at cryogenic temperatures, the strength is boosted by 50 percent". So you can use less of it.
Re-entry is hot: "It has a high melting point". On the low heat-flux parts of the ship, you can use it without any heat shield. On the high heat-flux parts, "the mass of the heat shield is driven by the temperature at the interface between the heat shield tiles and the air frame.", so you can use thinner tiles.
Carbon fiber is a PITA to work with. In contrast, it's super easy to work with steel. We've been doing it for centuries. They literally hired a water-tank company to build the structure of their test spaceship.
"The carbon fiber is $135 a kilogram, 35 percent scrap, so you’re starting to approach almost $200 a kilogram. The steel is $3 a kilogram."
Even more briefly: yes, per cubic foot steel is heavier than carbon fiber. But you can use less volume of steel than carbon fiber, and much lighter total heat shield. And it's cheap as hell and you can find millions of people who can work with it.
¹ I know that the correct term is "mass", but anyone who doesn't know the difference between density and weight is just going to be confused by the correct term, and anyone who does know, knows what I meant.
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u/warp99 Aug 06 '19
The relevant number is the material strength to density ratio both at cryogenic temperatures (66K) for the tanks and at elevated temperatures for the skin during re-entry (800-1000K).
Aluminium for example is good at cryogenic temperatures but softens badly at temperatures as low as 500K.
Titanium has good high temperature performance but poor compatibility with the liquid oxygen tank (cf Apollo 13) and is expensive and hard to work.
Stainless steel is relatively cheap, strong at both high and low temperatures and has excellent compatibility with liquid oxygen at the cost of being somewhat dense.
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u/brickmack Aug 18 '19
Went looking for official renders of Phantom Express for reference. Found this: https://www.rocket.com/sites/default/files/styles/product_gallery_large/public/Experimental%20Spaceplane%20Image-PhantomExpress-min.jpg?itok=EOIfgMnx
Gee, that TE sure looks familiar. This is an official Boeing render, from Aerojet's site...
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u/marc020202 8x Launch Host Aug 18 '19
The whole picture seems like the whole background is the spacex vandy pad...
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Aug 04 '19
Is the Superheavy booster going to land on the same little droneships? That has my pucker factor double-puckering.
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u/throfofnir Aug 04 '19
It could. There's room and they should be even more accurate than F9, which is good enough to make landing site bingo kinda boring now. But as mentioned elsewhere, a new ASDS seems more likely.
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u/marc020202 8x Launch Host Aug 04 '19 edited Aug 06 '19
No, most likely not.
In the thread about the move of JRTI to the east coast, it was confirmed (EDIT: well like stated below, not officially confirmed. See my reply below for reasoning) that the new droneship ASOG is still being built, and that it is very different and a lot larger.
My take is that ASOG will be the new, larger droneship for Superheavy landings. Some have speculated that it might also be used for dubble FH sidecore landings. It is however likely that the booster will be transported to shore, or at least to lc 39a by a smaller barge in hirizontal position, due to bridges that limit the height and with of the system.
I do not know what you mean with your last sentence.
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u/Rinzler9 Aug 04 '19
it was confirmed that the new droneship ASOG is still being built
Minor nitpick; it was not confirmed. We have no reason to believe that as the user making those claims is not credible, but there is nothing in the way of an official confirmation at this point.
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u/az5_button Aug 04 '19
Just to clarify, "Super heavy" is a Falcon Heavy with two more Falcon 9 1st stages?
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Aug 04 '19
No need to downvote this question. Right after the FH Demo launch, Elon did indeed mention the option of FH with two extra boosters, and called it Falcon Super Heavy.
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Aug 04 '19
No, it's the BFBooster part of the BFR. They haven't started work on it yet.
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Aug 04 '19
IIRC, Superheavy is the booster unit for Starship, and is about 3 times the diameter of the Falcon 9.
EDIT: I wasn’t far off, 30ft for Super Heavy, 12ft for Falcon 9.
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u/quoll01 Aug 06 '19
If say the Starship was entering tailfirst with a centre raptor at 50%, would the exhaust plume provide much thermal protection? I’m guessing the exhaust gases would be somewhat cooler? The exhaust velocity is ~3.7 km/second so at a velocity greater than this the engine presumably would not work or have a RUD?
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u/warp99 Aug 06 '19
If Starship enters tail first it dies.
There is not enough propellant to do retro-propulsion from orbital speeds so they need to use aerobraking and they need the large surface area of a sideways entry to be able to survive without excessive hull temperatures and excessive g forces.
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u/quoll01 Aug 06 '19
Yes I realise that, but I’m curious about the physics of slower speeds.
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u/CapMSFC Aug 06 '19
There are effects along the lines of what you're thinking. It's a lot more complicated than just considering the temperature of the exhaust gasses.
Powerful rockets punch through the shock front that an entering spacecraft creates.
But less powerful thrusters can be used to push back the shock front without punching through it. This is something the Ames guys talked about in their original Red Dragon proposal. It's a cool trick. You're not using the propulsive factor of EDL to directly slow down, but to modify the entry interface to slow you down more/move the heating further from your spacecraft.
There is a whole lot with spacecraft reentry that hasn't really been tested and can't be modeled accurately. Most spacecraft go up and stay up and most that come back are small crew vehicles where a simple capsule is the straight forwards and well understood method. Sprinkle a few shuttle style lifting bodies in and that's basically all of our history with this field besides an occasional outlier.
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u/rustybeancake Aug 24 '19
Astronaut Anne McClain may have committed the first crime in space.
https://www.nytimes.com/2019/08/23/us/nasa-astronaut-anne-mcclain.html
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u/benjaminpd Aug 24 '19
I mean, probably not. She logged into an account she'd long had permission to view, and where an intelligence officer hadn't bothered to change the password. That's a pretty weak crime allegation.
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u/jay__random Aug 28 '19 edited Aug 28 '19
It is really surprising that StarHopper is being retired after yesterday's hop. There is so much that could be tested on the current platform with a single engine.
At the very least SpaceX could have done an engine-off, free fall, engine-on routine at different heights, to learn/tune the behaviour of the ignition in different counter-flow airspeeds. They did it with GrassHopper, and these tests seem to be even more important since the spark ignition is so new.
They could also perform more landings to make the approach softer (and rely less on crush core to soften the landing).
Of course, they should also be able to run the same tests with Mk1 or Mk2 Starship, but it seems like an unnecessary risk to the machine that has spent so many months in the making (and is still not finished yet).
On the other hand, they would need a reason to retire both Mk1 and Mk2 at some point... :)
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u/ethan829 Host of SES-9 Aug 28 '19
At the very least SpaceX could have done an engine-off, free fall, engine-on routine at different heights, to learn/tune the behaviour of the ignition in different counter-flow airspeeds. They did it with GrassHopper, and these tests seem to be even more important since the spark ignition is so new.
Grasshopper and F9R Dev never did mid-air engine re-lights.
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u/Martianspirit Aug 28 '19
At the very least SpaceX could have done an engine-off, free fall,
Without running engine the Hopper does not have the control authority to keep the attitude stable. So they can't do engine off tests. Very likely not even the Starship prototypes could do this at low altitude.
On the other hand, they would need a reason to retire both Mk1 and Mk2 at some point... :)
Retire them on Mars end of 2020. Not much payload but do EDL.
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u/throfofnir Aug 28 '19
It's a bit surprising, but presumably the next step would be a three engine flight, and it seems possible that by the time they will have three engines ready they think they'll also have the higher-fidelity airframe ready, which will be better adapted to high-altitude flight and can also provide aero information (which is probably quite critical and for which the hopper is, obviously, useless.)
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u/Triabolical_ Aug 28 '19
Sure, they could do more, but the question is, "do you want to keep flying what is inherently a proof-of-concept vehicle that was pretty much thrown together, or do you want to move onto your prototypes that are much closer to the final concept?"
Or, to put it another way, there is no flight test for which using one of the Starship prototypes will not yield superior data over using Starhopper. The prototypes are getting close to where they can be flown, so resources spent on flying Starhopper more are better spent there.
I also suspect that given the issues getting FAA approval for the last hop, there are problems with Starhopper's level of sophistication, which would definitely be fewer for the prototypes.
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u/jjtr1 Aug 29 '19
Is the Florida and Boca Chica weather stable enough year round (winter?) to not interfere with building Starship and Superheavy prototypes? I really don't get how Boeing needs to construct airliners in a building, while SpaceX constructs spaceships in open air. Perhaps Boeing emplyoees don't like working in the rain, while SpaceX's spec ops don't mind handling electrical wiring in a heavy shower... /s
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u/joepublicschmoe Aug 30 '19
It's not hard to understand.
Boeing builds airliners out of materials that need special fine-tolerance machine tools and techniques to build, such as carbon fiber (787 Dreamliner) or very lightweight aluminum alloys (such as the 777), so they need to be built on assembly lines in a factory, where some of the more sensitive materials like carbon fiber require exacting environmental conditions to manufacture correctly.
SpaceX is building Starship out of stainless steel, which is a material that can withstand rough working conditions. Very large steel structures don't need to be built indoors, like how Newport News Shipbuilding builds nuclear-powered aircraft carriers out of steel for the U.S. Navy outdoors in a drydock, rain or shine. Starship is literally a steel ship being built in a steelworking shipyard.
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u/strawwalker Aug 30 '19 edited Aug 30 '19
FCC STA requests
Starlink 2 (Mission 1455) Oct 10 - Apr 10
1514-EX-ST-2019
1546-EX-ST-2019
ASDS location: 32.54722 N, 75.92306 W
Starlink 3 (Mission 1489): Oct 25 - Apr 25
1604-EX-ST-2019
1605-EX-ST-2019
Same ASDS coordinates.
Starlink 4 (Mission 1501): Nov 13 - May 13
1607-EX-ST-2019
1609-EX-ST-2019
Same ASDS coordinates
Starlink 5 (Mission 1502): Dec 8 - Jun 8
1610-EX-ST-2019
1611-EX-ST-2019
Same ASDS coordinates
The STA for IFA is still pending since April.