So SpaceX has been selected to develop a version of Starship that will land astronauts on the Moon, and return them to the Orion capsule orbiting the Moon. Is the Starship HLS (Human Landing System) profile substantially different than the Starship prototypes we have seen in the high altitude tests? By that I mean, will it look more like an Apollo lunar module, or more like a Starship prototype? Because if it is more like the Starship prototypes, I have a question.
The Starship prototypes are 165 feet tall; add landing legs suitable for a lunar touchdown and launch, and it could be even taller. If the crew compartment is near the top of the Starship, how are the astronauts going to get down to the lunar surface? An elevator? A ladder?? Neither seems practical or efficient.
Is this a challenge that must still be overcome, or have they got a potential design that avoids it?
Is that elevator located within the fuselage of Starship, terminating somewhere near the Raptor mains? Or is it bolted to the outside of the Starship? Either way, it seems problematic. Within Starship, it has to get past fuel and oxidizer tanks, then find room between the engines for the exit. And if it is bolted on the outside, it seems like it would create significant drag and mechanical stress during ascent though the atmosphere. Need more information.
I think the elevator is inside the hull; a door opens and a platform suspended from the top comes out, and then is lowered along the outside. I don’t think there are tracks on the outside of Starship, it’s just suspended from above, but I could be wrong.
Blue Origin’s design is also quite tall and uses what’s been described as the Ladder of Doom. The last design has only a small set of steps to enter.
I don’t think we kmow yet whether the elevator will have exterior tracks or not. I’ve seen renders of both. But it definitely descends on the outside of the rocket. Also, there are two of them for redundancy - one on each side of the rocket. But all that is still subject to change as the design evolves.
The lunar Starship has a huge advantage over the other entries - it’s fully reusable. Thr Blue Origin lander leaves its descent stage on the Moon like the original lander did. That’s fine for a one-off mission, but for a sustainable lunar presence, which NASA says it wants, throwing away all that hardware on every landing will get very expensive. Starship HLS can take off and land repeatedly after being refueled in lunar orbit.
The other interesting thing about Starship HLS is that it doesn’t land using the main engines. Rather, there is a ring of 28 smaller engines in the upper half of the rocket which will do the last part of the landing. This is to avoid blowing lunar regolith all over the Moon or even to Earth orbit on each landing.
The thing looks like a Starship, but it’s really radically different. No flaps, no heat shield, and a completely different landing system, plus a gigantic crew/cargo compartment.
Something more like a basket that’s suspended from a crane is certainly doable. The Moon (obviously) lacks wind, so that problem is solved. And the lower gravity means the crane, cable, basket, etc., can all be silly-flimsy by Earth-based standards.
There’s no pancaking in Kerbal, just the bottom bits of your vehicle will explode if you come in too hot. This is detrimental to the mission if those pieces were necessary for returning to orbit.
Bah. Jeb has the ability to stay on another planet indefinitely. In case of Rud, he can just wait a year or two until you get around to a rescue mission.
I think I left Jeb in orbit a few years ago. He’s a patient guy.
I guess the ability to deliver a lot of cargo is necessary for a continued presence. This apparently isn’t the Apollo Program done over, it is something out of a Ben Bova novel.
The most recent render shows tracks. Not that anything is set in stone yet, but that seems to be where they’re leaning.
The weight is still supported by a small crane, though. I don’t think the tracks would be very strong; they’d just be there to prevent the basket from swinging and possibly colliding with the spacecraft. No wind, but astronauts moving around or motor vibrations somehow creating a resonance could get the basket moving in a way they don’t want. A passive track would solve that issue.
Yeah,. I agree with all that. The downside is that it would really suck for the tracks to get gummed up with lunar dust and prevent astronauts from getting back into the ship. I imagine there could be some sort of emergency procedure to pop the basket off the tracks if that happened.
Or just have the cable connected to a quick-release hook, which could be disconnected from the basket and hooked directly to an astronaut. Then leave the basket behind.
The crane is just a winch with a cable. Gummed-up tracks couldn’t stop that from working as long as the cable could be disconnected and attached to something else, like a loop on the spacesuit.
There could be a concern if the basket got stuck halfway up. Even if the basket could be disconnected from the track, an astronaut would have to get there somehow and futz with the glider system.
At any rate, I think this is a pretty unlikely scenario. The track can be made with a lot of tolerance to it. It’s just there to prevent the basket from swinging all over the place. I’m thinking a shoe with plastic wheels on the inside and outside, and some springs for compliance, would work just fine. It could have centimeters of tolerance; more than enough to deal even with a lot of moon dust.
