Comment by sho_hn | Hacker News Reader

Comment by sho_hn | Hacker News Reader

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Which gives me great amusement about the current human spaceflight plan to land upright Starship on the moon, and lower astronauts from the top of what is effectively a tower-like 13-story building (52.1m without landing legs, at 9m tube width) using some kind of elevator solution. To put things into perspective, this is roughly the same height as the Leaning Tower of Pisa, and with landing legs extended probably about the same width as well.

https://en.wikipedia.org/wiki/Starship_HLS#/media/File:HLS_S...

https://www.nasa.gov/image-article/nasa-astronauts-test-spac...

Sure, there's lots of details to consider, e.g. center of gravity, overall weight, maximum possible duration to hover and ability to accurately steer and pick your landing spot. But the inherent difficulty in "how do you not topple over" is definitely there, and it's clear the proposed Starship lander will have to outperform these IM landers significantly.

That said, if you want to scale out payload to the surface I guess you have to (which however eats into your center of gravity advantages from having lots of engines at the bottom, too).

At least they're likely to do unmanned test landings until they successfully land upright. But it seems nobody followed the design of the appollo lander, except the Blue ghost which landed successfully last week.

If they can control the angle of each leg with enough precision, that might be enough to compensate for (slightly) uneven terrain.

I understand that the recently successful Blue Ghost has sensors to detect suitability of the landing spot, and used it to re-position twice while landing. Starship would probably need something like that, too.

with enough energy(like starship would have), i suppose you could get out of an irrecoverable tipping over motion by just lighting the engines and trying again. Before you fall, obviously. "works in KSP"^TM

> how do you not topple over

Projectile grappling-hooks to embed into nearby ground then winch the line taught? Just have to make sure all are launched at the same time with force vectors that cancel out. Maybe even launch them before touchdown so it doesn't topple over during landing if one of the feet land on a random rock.

My vote is for a large BattleBots style flipper that they flop their rover around with until it falls in their preferred orientation.

Just don't land too close to where the house robots are...

Could you land a weeble? So it wobbles and does not fall down.

I saw this episode of For All Mankind! It didn't seem to end well

I wonder what height you can safely jump from onto the moons surface?

Probably around 12 meters (40 feet or so?). That would be like falling 2 m (6 feet) on earth, which isn’t very safe but pretty doable. Maybe 8 meters to make it more safe?

That’s based on impact speed.

Probably less than that. Consider your suit needs to survive without a tear.

Oh I guess the suit is going to prevent you doing a parcour roll!

Starship is simply due to the desire to have a Sci-Fi looking ship land on a planet. It’s not being done for practical reasons. It’s being done because it looks cool.

To learn more about the strategy for landing on the moon, listen to this audiobook. Extremely good.

The Man Who Knew the Way to the Moon

hey the leaning tower of pisa is still standing, clearly this precedent means that starship HLS will be stable

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