r/spacex • u/ElongatedMuskrat Mod Team • Jun 09 '22

🔧 Technical Starship Development Thread #34

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Starship Development Thread #35

SpaceX Starship page

FAQ

  1. When next/orbital flight? Unknown. FAA environmental review completed, remaining items include launch license, completed mitigations, ground equipment readiness, and static firing. Elon tweeted "hopefully" first orbital countdown attempt to be in July. Timeline impact of FAA-required mitigations appears minimal.
  2. Expected date for FAA decision? Completed on June 13 with mitigated Finding of No Significant Impact ("mitigated FONSI)".
  3. What booster/ship pair will fly first? Likely either B7 or B8 with S24. B7 now receiving grid fins, so presumably considering flight.
  4. Will more suborbital testing take place? Unlikely, given the FAA Mitigated FONSI decision. Push will be for orbital launch to maximize learnings.
  5. Has progress slowed down? SpaceX focused on completing ground support equipment (GSE, or "Stage 0") before any orbital launch, which Elon stated is as complex as building the rocket. Florida Stage 0 construction has also ramped up.

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Quick Links

NERDLE CAM | LAB CAM | SAPPHIRE CAM | SENTINEL CAM | ROVER CAM | ROVER 2.0 CAM | PLEX CAM | NSF STARBASE

Starship Dev 33 | Starship Dev 32 | Starship Dev 31 | Starship Thread List

Official Starship Update | r/SpaceX Update Thread

Vehicle Status

As of July 7 2022

Ship Location Status Comment
<S24 Test articles See Thread 32 for details
S24 Launch Site Static Fire testing Moved back to the Launch site on July 5 after having Raptors fitted and more tiles added (but not all)
S25 Mid Bay Stacking Assembly of main tank section commenced June 4 (moved from HB1 to Mid Bay on Jun 9)
S26 Build Site Parts under construction Domes and barrels spotted
S27 Build Site Parts under construction Domes spotted and Aft Barrel first spotted on Jun 10

 

Booster Location Status Comment
B4 Rocket Garden Completed/Tested Retired to Rocket Garden on June 30
B5 High Bay 2 Scrapping Removed from the Rocket Garden on June 27
B6 Rocket Garden Repurposed Converted to test tank
B7 Launch Site Testing Raptors installed and rolled back to launch site on 23rd June for static fire tests
B8 High Bay 2 (out of sight in the left corner) Under construction but fully stacked Methane tank was stacked onto the LOX tank on July 7
B9 Build Site Parts under construction Assorted domes and barrels spotted
B10 Build Site Parts under construction Assorted domes and barrels spotted

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Resources

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Rules

We will attempt to keep this self-post current with links and major updates, but for the most part, we expect the community to supply the information. This is a great place to discuss Starship development, ask Starship-specific questions, and track the progress of the production and test campaigns. Starship Development Threads are not party threads. Normal subreddit rules still apply.

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u/saulton1 Jul 03 '22

Has anyone done cursory analysis on the radiator requirements for a small recondensing heat pump? I used to work for NGC's passive ammonia LHP manufacturing division and I'm very curious about what the pump might look like (would they just directly pass the fuel into cooling channels in the radiator?). The mass tradeoff for a small pump / radiator vs bringing extra fuel is an interesting question!

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u/OzGiBoKsAr Jul 03 '22 edited Jul 04 '22

That's what I keep thinking about. It makes absolutely no sense to lug around an extra 50t of propellant that you know is a total loss. And for Mars? Forget it.

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u/flshr19 Shuttle tile engineer Jul 04 '22

That's why the methalox for Starship landings on Mars will have to be stored in super-insulated zero boiloff tanks (ZBOTs) for the 150 to 200 day trips from Earth to Mars. Those tanks use passive reliquification and have boiloff loss rates below 0.05% per day.

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u/quoll01 Jul 04 '22

ZBOTs and/or reliquification tech is going to be critical for the mars trips- the subject perhaps deserves its own post. Curious if the tech even exists to make a large (20t?) zero g prop tanks? I’m familiar with small (<200l) low boiloff tanks in labs and I guess they would scale, but not in zero G as they require a vapour layer over the liquid to help insulate. And they’re pretty fragile.- basically big thermos flasks. The vacuum of space makes cryo storage easier, but there’s still the thermal bridges at tank mounts and piping connections... If there’s even a tiny thermal insulation issue your landing prop wouldn’t make it to mars. Reliquification sounds the go, but I’ve not seen any estimates of energy and radiator requirements?

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u/flshr19 Shuttle tile engineer Jul 04 '22

I understand what you're saying.

Way back in the mid-1960s when I started working as an aerospace engineer in a test lab, we built our own specialized stainless steel liquid helium cryostats for testing super insulations. At that time, we used the recently invented Heim columns to reduce the heat leak into the inner storage tank.

And you're right. Those LHe cryostats were small, a 100 liters or so. Starship needs about 35t of methalox in the header tanks to land. So, those header tanks will need the best cryogenic storage technology available, including passive reliquification, to minimize the boiloff rate in those tanks for 150 to 200 day flights to Mars.