[rob74]

So the Artemis part of the program (the "pension plan") is just doing something that pretends to be marginally useful for insane amounts of money to secure political support through the jobs it enables at various companies strategically spread across the US (plus support from the international partners involved), while the hope is that the HLS part of the program (the "lottery ticket") will eventually succeed in making the other part redundant?

But still, I think the article has a point when it describes the difficulties of landing Starship on the moon and being able to lift off again several days later. Landing a rocket on its tail is cool when the only consequence of a failure is not being able to reuse the rocket, but when there are human lives in the balance, it starts to sound really scary. Not to mention the possibility of damaging an engine during the landing or of fuel loss preventing them from lifting off again...

[jlangenauer]

It's a fair point, but the only way at all to land on a body that has no atmosphere is to use rocket engines that point down. The Apollo Lunar Module landed on its "tail", though it did at least have a separate ascent stage with its own engine, so might have had some chance of taking off again if the landing was damagingly hard.

[kqr]

I would argue plenty of lander designs (including LM) were tailless and landed on their butts! That should be easier than the balancing act of standing on the tail.

[rst]

The point is more that compared to prior landers, the Starship version at least has a uniquely high center of gravity over a narrow base, which makes it a whole lot easier to tip, and amplifies the consequences of, say, leg damage.

[dotnet00]

The center of mass should be pretty low relative to the height of the lander, the engines and propellant are the heaviest parts, the engines are obviously at the bottom. The heaviest component of the propellant is the LOX, which is also at the bottom.

[williamDafoe]

This is false most of the fuel is gone by the time it lands and most of the payload is up high that's why the latest designs for starship have diagonal thrusters 2/3 of the way up the rocket so they can stabilize the top heavy part of the rocket without having to control it from a high moment arm

[dotnet00]

Starship carries ~1200t of propellant, of which ~950t is LOX, and 250t is Methane. While yes, most of that will be burned off by landing, it'll still need enough to return to lunar orbit. Even if we assume that only 10% of the fuel is needed to return to orbit, that's 95t right on the bottom with another 10t of engines and most of the 100t of dry mass of the Starship itself (plumbing, tank domes etc).

The thrusters you're (probably) thinking of are the landing thrusters that NASA thinks they might end up needing. Not to stabilize the rocket when on the ground, but because the Raptors might be too powerful and might dig out a crater underneath the vehicle when landing on an unprepared surface (such as the Moon, at least before a base is established or something is sent to prepare a proper surface). Placing weaker landing thrusters up top eliminates this issue, although at the moment they're still considered speculative in the sense that last we heard (which was admittedly a year or two ago), SpaceX are not convinced that this will be an issue.

Thrusters would anyway be a crazy approach to preventing a crewed vehicle from tipping over, as you wouldn't want them to be firing when the crew are doing any of the things that would involve the ship becoming potentially unstable (eg unloading cargo). For stability they'd have to use the large self-leveling legs from the original HLS design.