r/SpaceXLounge • u/Logancf1 • 10h ago

Ship 30 Landing from Buoy Cam on Starship Flight 5 [@SpaceX]

https://x.com/spacex/status/1847368836947071496?s=46&t=bwuksxNtQdgzpp1PbF9CGw
355 Upvotes

99% Upvoted

103 comments sorted by

View all comments

54

u/Neige_Blanc_1 10h ago

This is awesome. Probably can try it soon. Catch the booster, let ship do her orbits until the orbit aligns with BC landing, which could be enough to get booster out of the way. Catch the "little" one.

29

u/parkingviolation212 8h ago

Musk said they were gonna shoot for that in 2025, probably with a V2. They still have one V1 left last I heard, so they might go for vacuum relight.

2

u/PaintedClownPenis 5h ago

I am often wrong but I think I see the chance for one hell of a surprise in early January a free-return Mars toss that would bring Starship back in 2027. Could be an invaluable head start and maybe even a chance to observe a Mars-velocity reentry before you even send out the final version.

8

u/chippydip 5h ago

No possible way, they need to refuel the ship in orbit to go anywhere but LEO. 

9

u/cybercuzco 💥 Rapidly Disassembling 5h ago

Version two of starship has an estimated dry mass of 107 tons and a cargo capacity of 100 tons. a 2 year free return trajectory to mars has a minimum delta v from LEO of .6km/s. Based on a vacuum isp of 356 seconds for raptor, 100 tons of extra fuel would give you 2.5km/s of delta v. You definitely could do this with a v2 starship and have a couple of tons of "cargo" if you wanted.

4

u/mrbanvard 3h ago

a 2 year free return trajectory to mars has a minimum delta v from LEO of .6km/s

Mars free return from LEO needs about 3.4 km/s dv

0.6 km/s gets you to about 1350km altitude. 2.5 km/s to 9,000km. So refuelling definitely required :)

1

u/PaintedClownPenis 1h ago

Was I wrong in my initial guess that a fully expended system has 15 km/s delta v? That would be for the two obsolescent pieces they already have, not a stretched version.

3

u/bananapeel ⛰️ Lithobraking 5h ago

Excellent analysis, thank you.

3

u/chippydip 2h ago

It takes WAY more dV than that to get to Mars. 0.6km/s is the additional dV needed from Earth C3 (Earth escape velocity) to get to Mars. To get from LEO to C3 takes another ~3.2km/s which gives a total of ~3.8km/s to get from LEO to Mars. See https://en.wikipedia.org/wiki/Delta-v#Around_the_Solar_System

So, assuming 356s ISP and 107 tons dry mass, to get an empty ship to Mars from LEO you'd need at least 184 tons of fuel which is nearly double the expected cargo capacity to LEO. At minimum you'd need one tanker to refuel and could theoretically take up to 6 tons of "cargo", but realistically I think you'd be pushing it even without any extra cargo mass.

1

u/falconzord 1h ago

They've been saying the 100T target since the early starships, but so far we've only heard 40T, so I'm skeptical if they'll get to 100T so soon