Moonshot goes sideways as Intuitive Machines' second lunar lander seemingly falls over For the second time this week, a privately operated spacecraft has touched down on the Moon – but this one landed badly. The Athena lander, built by Texas outfit Intuitive Machines, set down at 1730 UTC Thursday in the Mons Mouton region just 160 km (100 miles) from the South Pole of the Moon, after riding a SpaceX Falcon-9 …
Go down memory lane back to your childhood and make your own "Yaoki"
https://rainydaymum.co.uk/cotton-reel-car/
For added traction, cut perpendicular grooves into the flanges of the reel, so they resemble a gear wheel
We used to run those along tracks made in the sandpit, sometimes past castles, sometimes through craters (artisanal craters, made - when adults weren't watching - by artful application of "meteorites" thrown down as hard as we could). Not in the least bit competitive, of course. But - use a warmed knife to cut slices of a candle, pull them of the wick and thread the elastic through the hole; reduces the friction. And wooden reels are better (It were all better in my day!).
After that, pullovers for goalposts...
These were great fun. The skill was in getting the tension just right: too many turns and it span out of control, too little and it had no endurance. The little grooves on the ridges enabled them to climb over small obstacles...... We sometimes put two on each side of a large matchbox to make a tank-like construction. This tank would 'attack' platoons of little plastic soldiers whose only defence was another rubber-band powered field-gun.
Football on the street; having to pause the game when a car/milk-float/coal-wagon approached. Any passer-by could join the game, if they dared....
Cheery times ---->
Great cars have little cars upon their backs to bite 'em,
And little cars have lesser cars, and so ad infinitum.[1]
An intriguing idea; the video talks about the dust affecting the rover, but - they didn't give the AstroAnt a broom?
[1] Sorry, not up to level of the velocity/viscosity variation; looking forwards to someone else's better attempt
It's often said that landing on the moon is hard. And the 50% or so failure rate seems to bear this out. But I'd like to point out that that applies to unmanned probes only.
When Eagle came down over a field strewn with large boulders during the Apollo 11 mission, Neil Armstrong famously took control and piloted the LEM away from almost-certain disaster (flying on his last few drops of fuel, if memory serves) and saved asses, the mission and the day. All Apollo landings went off without any major failures.
While I realize the sample size is limited, this suggests to me that, when landing on the moon, a skilled pilot at the controls makes all the difference. Which means that landing on the moon is hard... for robots.
That said, commiserations are in order. Intuitive Machines has got the "reaching the moon and landing softly" part all worked out. A shame about the "not falling over upon landing" part. Hang on in there, guys.
They seem to have landed well enough to survive so all the difficult stuff was OK, the issue seems to be more from creating a design that just isn't stable enough.
Ego can convince an engineer that their design is fine, or proximity to the boss can make them proclaim it as such, but they've done something different to usual practice that looks like it has inadequate supports and/or could topple easily and funnily enough it has now done that repeatedly.
For all the effort they maybe should have started with something slightly more conservative/known to work and only then iterated to something more innovative?
Or built systems to enable it to right itself after landing. Airbags, or extendable legs that are stowed up against the body seem the obvious answers.
I wonder whether the root of the problem is that they've worked on the basis of landing on a flat(ish) moon and in fact it's covered in boulders and craters that make the ground uneven enough.
Any additional kit will add to the volume and weight and increase costs.
I think it's the low gravity and lack of atmosphere that's the problem: bouncing is inevitable and there is no friction to limit the inevitable twisting and the centre of gravity has a much more limited effect. This is very hard to model, but having it happen twice suggests that they haven't learned all the lessons, the first of which is getting there in one piece is better than adding capability.
The low centre of gravity is less effective in low gravity. If the lander is moving horizontally then there is a very high risk that a leg will meet a random small boulder and start to rotate.
If it descends vertically with no lateral movement there is still a chance that one or two legs on one side will meet a boulder before the other side, or there will be a trench and again there will be rotation.
Maybe a design where it doesn't matter which way up it lands would increase chances of success.
"Maybe a design where it doesn't matter which way up it lands would increase chances of success."
-- Caltrops? They always land point up, given a mostly level landing spot. --
Surely, a design with an internal, spherical "rover garage," servos to rotate it to a post-landing horizontal orientation, along with multiple exit doors (think "wiffle ball" exterior) and either ramps, or maybe (redundant) external cranes, enabling lowering/deployment, no mater what angle the landing resulted in, could be designed?
Externally, maybe longitudinal tracks, with teeth, along with gears and servos to move packages, could result in semi-optimal solar panel, antennae, and (deployment) crane deployment?
Alternately, maybe some custom shaped, inflatable, airbags, or telescoping (pneumatic or hydraulic) legs on the exterior, to "correct" the orientation (push it upright)?
Cost (that old "project killer"), is the big problem. This would be much more expensive than the current "assume it lands upright" design philosophy.
This is an economic ("financing") problem first, then an engineering problem.
"the issue seems to be more from creating a design that just isn't stable enough."
It appears that Athena came down in a boulder field some 400 metres from its intended landing spot. That's exactly what Neil Armstrong managed to avoid, thus proving the advantages of a human pilot over the guidance system of an automated probe.
I imagine image recognition, more advanced terrain scanning upon final descent and more flexible algorithms (perhaps AI) will improve the success rates in the future. But for now (as it has been in the past 60+ years) the absence of a human looking down and saying "Hang on, this isn't going to work; let's pick that better spot over there instead" we're going continue seeing more of this.
It didn't matter what the landing conditions were like, all of the Apollo pilots were, well, pilots. There was zero chance that any of them would have allowed the computer to land them, not when they had perfectly good manual controls.
Fortunately it was fly-by-wire, so the computer was in the loop all the time to make sure they didn't mess it up ;)
and now empty fuel and oxidizer tanks are up high. They went with two stacked tanks, instead of Blue Ghosts four tanks arranged around the center and loiwer down.
This doesn't bode well for Starship landing on the moon either.
For example, most big (and little) cranes are spec'd to be level to within 1% or their load charts drop off precipitously. Just a little off plumb and things start looking really really bad.
I don't think the design is the problem. If you have sufficient fuel margin than a landing shouldn't be too difficult. But their choice of a laser altimeter over a radio altimeter turned out to be a mistake. The laser altimeter returned "noisy data" which the flight computer couldn't make sense of. I'm surprised they didn't resolve this during development since you should see similar results during testing here on Earth.
To me this sounds like "back to the drawing board" for Intuitive Machines. I doubt they can solve this with a software update.
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