281–290 of 360 posts
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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.
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Humans - and the mostly empty space they require - up top. Fuel, engines, and water will be at the bottom. (For practical examples, look at the F9 first stage, or the Starship prototypes they've already tested.)
Fuel will be a huge percentage of the weight, and won't that be mostly exhausted after taking off and then doing a powered descent? The center of gravity will move quite a bit upwards.
Also you'll need to assume for at least the foreseeable future that any Starship HLS landing will require sufficient fuel to return to orbit.
With enough margin left you can very reasonably adjust the center of balance by using multiple tanks and pumping all the fuel into rear tanks.
That should be enough given that the Starship HLS is estimated to have around 1.5 million kg of fuel at max capacity and only 100k kg of payload to the lunar surface (200k kg payload max for non-landing starship). That makes the payload mass to lunar surface only 6-7% of the total fuel capacity.
So outside of an extremely risky "attempt landing with no fuel left for an abort or return to orbit", you'll have at least double to quadruple the weight of the payload in just fuel alone.
Now for an earth landing of course the calculus here is different, especially since Starship's earth landing strategy explicitly requires throwing the vessel on it's side during the "bellyflop" and only pulling out of that fall with a powered landing at the last possible second.
TLDR No. Where center of mass will be able to make a difference fuel will make up significantly more mass than the payload.
Good advice: 1. Never invade Russia in winter. 2. Make sure your robotic lunar lander has a low center of gravity.
With the lack of atmosphere is that there is no 'natural' attitude/orientation correction. If you're tilted 5 degrees then you'll stay that way. With an atmosphere drag and aerodynamic forces can be used to ensure a proper orientation.
'Just make sure you come down straight' isn't so easy because when you enter the Moon's 'orbit' (not necessary, speaking colloquially) you're traveling extremely fast. And so to land you need to zero out your horizontal and vertical velocities. You do this by literally turning around the opposite direction and thrusting. And then you need to simultaneously also ensure your vertical velocity stays near zero as you approach the surface.
And then finally you need to come down with your vertical velocity at near zero, your horizontal velocity at zero, and perfectly orientated. This is really friggin hard. If you have even a hair of velocity you're going to bounce, skid, and otherwise do nasty things - which is why so many landers end up on their side, if not upside down. And then there's the Moon's surface itself. Come in on an even slightly unlevel terrain and again you're in for a wild ride.
These 2 failures could have been easily avoidable both times. I really wish there was a push in the US government to create and stockpile plutonium-238 and ensure it's readily available, subsidized, and offered for all US probes/rovers/other scientific instruments in space (whether it be for NASA's use who currently has to ration because of how little they have left, or for private use after approval). Like, why aren…
1. https://www.jpl.nasa.gov/news/nasas-juno-spacecraft-breaks-s...
2. https://www.nasa.gov/missions/europa-clipper/nasas-europa-cl...
These 2 failures could have been easily avoidable both times. I really wish there was a push in the US government to create and stockpile plutonium-238 and ensure it's readily available, subsidized, and offered for all US probes/rovers/other scientific instruments in space (whether it be for NASA's use who currently has to ration because of how little they have left, or for private use after approval). Like, why aren…
But if you "just" want to put a probe on the moon, solar panels weigh less than plutonium.
These 2 failures could have been easily avoidable both times. I really wish there was a push in the US government to create and stockpile plutonium-238 and ensure it's readily available, subsidized, and offered for all US probes/rovers/other scientific instruments in space (whether it be for NASA's use who currently has to ration because of how little they have left, or for private use after approval). Like, why aren…
You are one internet search away from finding the specific power of RTGs and of solar panels on the moon.
These 2 failures could have been easily avoidable both times. I really wish there was a push in the US government to create and stockpile plutonium-238 and ensure it's readily available, subsidized, and offered for all US probes/rovers/other scientific instruments in space (whether it be for NASA's use who currently has to ration because of how little they have left, or for private use after approval). Like, why aren…
Generally I agree, but Moon is not a bad place for solar panels if a spacecraft has no contingencies and is able to harvest energy during Moon's day and store it in batteries to be used over the night. The sufficient power can be generated by a solar panel of the size (or even smaller) of the spacecraft itself. The other story is for missions like Juno [1] or Europa Clipper [2] which use solar panels near Jupiter - i…
There are always tradeoffs, it is almost never "why don't they just" case in spacecraft development.
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https://www.intuitivemachines.com/post/intuitive-machines-im... Look at the lander. Pray tell, if you want it shorter, where is everything supposed to go?
It could be two landers, one stacked on top of the other for takeoff, but separate for landing EDIT: or a horizontal lander, packed on it's side for takeoff. I'm sure it's more complicated than that, but landing something this tall seems quite complicated too in the first place.
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It could be two landers, one stacked on top of the other for takeoff, but separate for landing EDIT: or a horizontal lander, packed on it's side for takeoff. I'm sure it's more complicated than that, but landing something this tall seems quite complicated too in the first place.
go bigger this could be a pancake stack that separates into a swarm of puck like units according to some sequence
Seriously read digital apollo
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go bigger this could be a pancake stack that separates into a swarm of puck like units according to some sequence
You’d be paying the extra mass cost of landing gears for each pancake - something has to absorb the impact of landing or they’ll just break apart. These landers already operate at the margin.
This is probe #2 from the company - NASA did not get there until Apollo 11 they are not the same... Computers are almost a billion times faster.