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Comment by thePunisher | Hacker News Reader

I don't see Starship landing on the Moon. It's just too big and unwieldy and will likely topple upon touchdown.

The lunar lander variant they submitted to NASA has terminal landing thrusters at about >half of it's height (so about >25 meters high) for fine guidance during last stages of landing & to reduce the amount of dust and rocks sent flying by the rocket exhaust when landing on an unprepared spot.

Can be seen on picture in this article: https://spacenews.com/nasa-evaluation-sees-spacex-lunar-land...

Are you an aerospace engineer? Because the credibility of your comment hinges on that.

Hey, Kerbal Space Program is a perfectly valid alternative to a degree in Aerospace engineering!

EDIT: Obviously kidding.

Resume: -Designed and simulated entire spacecraft and rocket system for hypothetical moon landing. -Simulated thousands of spacecraft lithobraking events to assess spacecraft durability

Lithobraking might well become viable with some combination of tethers and electromagnetic accelerators to mediate.

No, but a friend of mine is and he said exactly the same thing.

Lots of it’s weight is in its butt. It will land fine.

Not really. The passenger and cargo area are on top and the fuel tanks are at the bottom, which will be mostly empty after landing.

IIRC Starship has a cargo capacity of 100 metric tons, all of it topside. The Raptor engines at the bottom will counterbalance this somewhat but it will still be top-heavy.

IIRC at least in some iterations starship has cargo pots at the bottom inside the "skirt" next to/between the vacuum optimized outer engines. That could help weight distribution & makes the pods easily acessible once you drop them to the surface post landing.

That’s my point. Those Raptors are heavy.

Not that heavy. A Raptor weighs 1500kg (1.5 metric tons) so 6 of them makes 9 metric tons while the weight at the top of Starship should be almost 100 tons.

That's actually a good remark. Dr. Zubrin argues that a full-sized version of Starship cannot land on the Moon unless it uses a landing pad, as it would create a large crater [1] and thus topple, and would also blow up the lunar rocks and dust in orbit [2], which would endanger any object orbiting the Moon (and Lunar dust is also quite corrosive).

One can speculate that's one of the reasons why the NASA proposal uses a mini-starship version.

[1] https://spacenews.com/op-ed-toward-a-coherent-artemis-plan/

[2] https://www.thespaceshow.com/show/11-feb-2020/broadcast-3459...

SpaceX already offered a solution: separate thrusters a few dozen meters off the ground. Current plan is for Raptors to be off for landing.

It's disappointing that Zubrin didn't mention that.

Zubrin has a recurring tendency to ignore things that don't support what he plans to say.

Fortunately, NASA does. That's why they accepted SpaceX's proposal bid to design a full version.

Gravity differences will make things very different from an intuition point of view.

To me it’s the huge distance astronauts would have to travel from the ship to the surface that seems like a serious demerit.

Given the low gravity, could they abseil down and just climb back up?

Ladders are hard. Proposal is elevator

Or a crane?

https://comicpunch.net/reader/mangas/The%20Adventures%20Of%2...

https://lh3.googleusercontent.com/proxy/I91epbDCEioqEofHg7FK...

And what if the lift fails? How are they gonna climb up 40 meters with a huge and bulky Moon suit?

It would be bummer if you had to die on the Moon because you couldn't climb back up into your spaceship.

The proposal has two separate crew access airlocks with their own lifts, two separate cargo cranes that can be used in an emergency, and presumably some rope on board that the crew remaining in the vehicle can jury-rig to drag the EVA team up if necessary.

The sheer scale of Starship is stupefying. If it ever gets there, it will in one go transport tens of times the payload of every previous lunar mission put together. The scale of what it can do will allow it to be quite a bit less efficient about things than everything else has to be, and so it can spend some mass on redundancy of important systems.

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