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I don't know. But in any case, it's not just the fuel. Have you seen the proposed Moon-Starship? They'd require some quite impressive crane to even get cargo i

by qayxc 6y ago

I don't know. But in any case, it's not just the fuel. Have you seen the proposed Moon-Starship? They'd require some quite impressive crane to even get cargo into the ship. Additionally, there's the problem of the landing site. It's considerably more difficult to land a rocket on unprepared, rocky terrain than on a carefully prepared landing pad. Plus a suitable area has to be found first, too. There's simply no guarantee the first Starship(s) even make it to the surface in one piece, let alone ready for refuelling and launch.

_Microft 6y ago
The moon-starship will not require in-situ resource utilization (ISRU), i.e. no creation of fuel and oxidizer at the target. It is supposed to land with enough propellants to make it back.
- qayxc 6y ago
  I only mentioned the Moon-Starship, because illustrations show nicely how far away from the surface the cargo bay is. I don't suppose the Mars version will be all that different in that regard, but we'll see.
  - _Microft 6y ago
    Ah, OK. The cargo bay door being that high up wasn't an issue in my eyes. They can build rockets after all, so they should be fine with engineering a platform and a lift. Edit: Numbers - for fun: if the cargo bay door is 2/3 up the rocket (at 33m from the ground), and someone fell off the platform of the crane at half this height (16m), they would hit the ground with a speed of 7.2m per second which is the speed they would have after falling a distance of ~2.6m on Earth.
valuearb 6y ago
Have you heard how weak gravity is on Mars? The crane can be made out of LEGO’s.
pharke 6y ago
Two things to consider: 1) They plan on working out orbital refuelling before sending a Starship to Mars, this might not be enough to return it to orbit from Mars surface depending on how much fuel needs to be used for Earth orbit departure but I wonder if it would be enough to decelerate into Mars orbit and have enough left over to return to Earth, this could open up some other possibilities which leads to #2 2) If they wanted to do a sample return mission, they might not need to land the whole Starship on Mars. If they put the Starship in orbit they could use it as a command module and send a Mars Lander down that was kitted out with enough fuel to return a sample to orbit. They should have about 330,000 lbs of payload to play with.
- qayxc 6y ago
  Interesting idea. The only issue I see with that is that you now have two orthogonal problems: a Starship to get into Mars orbit and back to Earth orbit and a lander capable of landing on Mars and returning to Mars orbit. Had SpaceX not cancelled their Red Dragon project, they wouldn't even have needed Starship for Mars sample return. NASA should have funded that back in 2014 - there would have been a sample return vehicle today and ready for launch two years from now...

by qayxc 6y ago

_Microft 6y ago

The moon-starship will not require in-situ resource utilization (ISRU), i.e. no creation of fuel and oxidizer at the target. It is supposed to land with enough propellants to make it back.

qayxc 6y ago
I only mentioned the Moon-Starship, because illustrations show nicely how far away from the surface the cargo bay is. I don't suppose the Mars version will be all that different in that regard, but we'll see.
- _Microft 6y ago
  Ah, OK. The cargo bay door being that high up wasn't an issue in my eyes. They can build rockets after all, so they should be fine with engineering a platform and a lift. Edit: Numbers - for fun: if the cargo bay door is 2/3 up the rocket (at 33m from the ground), and someone fell off the platform of the crane at half this height (16m), they would hit the ground with a speed of 7.2m per second which is the speed they would have after falling a distance of ~2.6m on Earth.

valuearb 6y ago

Have you heard how weak gravity is on Mars? The crane can be made out of LEGO’s.

pharke 6y ago

Two things to consider: 1) They plan on working out orbital refuelling before sending a Starship to Mars, this might not be enough to return it to orbit from Mars surface depending on how much fuel needs to be used for Earth orbit departure but I wonder if it would be enough to decelerate into Mars orbit and have enough left over to return to Earth, this could open up some other possibilities which leads to #2 2) If they wanted to do a sample return mission, they might not need to land the whole Starship on Mars. If they put the Starship in orbit they could use it as a command module and send a Mars Lander down that was kitted out with enough fuel to return a sample to orbit. They should have about 330,000 lbs of payload to play with.

qayxc 6y ago
Interesting idea. The only issue I see with that is that you now have two orthogonal problems: a Starship to get into Mars orbit and back to Earth orbit and a lander capable of landing on Mars and returning to Mars orbit. Had SpaceX not cancelled their Red Dragon project, they wouldn't even have needed Starship for Mars sample return. NASA should have funded that back in 2014 - there would have been a sample return vehicle today and ready for launch two years from now...