# Spacex Starship landing on the moon: how's that suppose to work? **URL:** \ **Category:** Factual Questions\ **Created:** [May 19, 2021, 1:47pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467 "2021-05-19T13:47:54Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [May 19, 2021, 1:47pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/1 "2021-05-19T13:47:54Z")
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? > **[Starship HLS](https://en.wikipedia.org/wiki/Starship_HLS?wprov=sfla1)** > > Pages for logged out editors learn more > > > > Starship HLS, or Starship Human Landing System, is a lunar lander variant of the Starship spacecraft that will transfer astronauts from a lunar orbit to the surface of the Moon and back. It is being designed and built by SpaceX under contract to NASA as a critical element of NASA's Artemis program to land a crew on the Moon in the 2020s. > The mission plan calls for a Super Heavy booster to launch a Starship HLS into an Earth orbit, where it wi... ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 19, 2021, 1:56pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/2 "2021-05-19T13:56:42Z")
An elevator, and it’s already designed and prototyped: > **[SpaceX rapidly builds, tests Starship Moon elevator for NASA](https://www.teslarati.com/spacex-starship-moon-elevator-nasa-prototype/)** > > As part of a NASA program that will select one or two commercial crewed Moon landers, SpaceX is busy testing Starship and prototyping hardware and most recently built and demonstrated an elevator “in a very short period of time.” Known as the Human... Iirc the SpaceX design overall was furthest along than the other two. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [May 19, 2021, 2:11pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/3 "2021-05-19T14:11:20Z")
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. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 19, 2021, 2:22pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/4 "2021-05-19T14:22:57Z")
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. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [May 19, 2021, 3:00pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/5 "2021-05-19T15:00:45Z")
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. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [May 19, 2021, 6:07pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/6 "2021-05-19T18:07:20Z")
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. ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [May 19, 2021, 6:25pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/7 "2021-05-19T18:25:19Z")
The proper Kerbal solution to this problem is jetpacks on your EVA suit. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [May 19, 2021, 6:29pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/8 "2021-05-19T18:29:16Z")
I thought the proper Kerbal solution was to pancake your rocket into the ground so you didn’t have far to climb out. Lithobraking also saves fuel. ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [May 19, 2021, 6:34pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/9 "2021-05-19T18:34:22Z")
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. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [May 19, 2021, 6:41pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/10 "2021-05-19T18:41:31Z")
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. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 19, 2021, 8:05pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/11 "2021-05-19T20:05:08Z")
> [@Gorsnak](#): > > The proper Kerbal solution to this problem is jetpacks on your EVA suit. Yes! Jet packs for the crew, a pulley and cable for cargo. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 19, 2021, 8:06pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/12 "2021-05-19T20:06:34Z")
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. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 19, 2021, 8:12pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/13 "2021-05-19T20:12:13Z")
> [@carnivorousplant](#): > > This apparently isn’t the Apollo Program done over Thankfully! We’ve been capable of much more for decades, but the will to do it has been lacking. Now we are finally pushing the boundary again. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 19, 2021, 8:21pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/14 "2021-05-19T20:21:59Z")
They will build living space, a solar array, and those little micro robots. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [May 19, 2021, 8:48pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/15 "2021-05-19T20:48:23Z")
> [@Sam\_Stone](#): > > I don’t think we kmow yet whether the elevator will have exterior tracks or not. The [most recent render](https://upload.wikimedia.org/wikipedia/commons/d/d3/Starship_HLS_Moon_landing.jpg) 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. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [May 19, 2021, 8:54pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/16 "2021-05-19T20:54:00Z")
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. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 19, 2021, 8:55pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/17 "2021-05-19T20:55:09Z")
I’m sure there will also be some kind of emergency ladder as well ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [May 19, 2021, 8:57pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/18 "2021-05-19T20:57:58Z")
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. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 19, 2021, 10:47pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/19 "2021-05-19T22:47:24Z")
I think the woory is that gummed tracks would stop the crane from working. They’d better have those jet packs, like Flash Gordon. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [May 19, 2021, 11:00pm UTC](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467/20 "2021-05-19T23:00:26Z")
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. Plus, there will be a second elevator as backup. [Next page](https://boards.straightdope.com/t/spacex-starship-landing-on-the-moon-hows-that-suppose-to-work/942467.md?page=2)