JollyPieFedSadly, Athena toppled over on the moon. With a lunar eclipse coming shortly, why didn't they design in a secondary power source over solar?
www.theguardian.com/science/2025/mar/07/athena-…
Even if it landed correctly, why would they plan a solar powered mission to the moon when our next lunar eclipse is in like 5 days?
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Admiral PatrickIf you ask me, they gave up far too easily.
Did they try repeatedly extending and retracting the landing struts and blasting the RCS to try to upright it?
What about using the reaction wheels to roll it downhill and popping the struts right before the bottom to launch it back up and using RCS to ease it down? 1 times out of 10 in KSP, that works for me. That's why my later builds always tack on the robotic science arm to the base and use it to nudge it back up.
stargazingpenguinThey should really hire KSP players to do these missions. We might put a ladder over the hatch or forget landing legs, but at least we know how to fix this issue!
jqubed
https://github.com/mockingbirdnest/Principia
https://github.com/dkavolis/Ferram-Aerospace-Research
https://github.com/KSP-RO/RealismOverhaul/releases
Hardcore KSP players run KSP Realism Overhaul + Principia + FAR/FARC
Takes off the training wheels and makes things much more realistic.
Real solar system, scales and values no longer on easy mode, much more complex and accurate physics calculations for orbital manuevers, much more realistic aerodynamics model.
If you can get an 'Oberth Kuiper' manuever to work in all that, a NASA employee might actually take at least momentary notice.
I would be shocked if the vast majority of them don’t already play KSP.
We've all had Kerbal Space Program missions that went like that.
This article was amended on 8 March 2025. The Athena craft touched down 250 meters, not 250 miles, from its intended landing site.
I bet they had "250m" in the report and the too-US-brained reporter went "hmm, yes. 250 miles"
Well it’s also a US company.
Sciences and space has used SI for ever….
geneva_convenienceWell it’s also a US company.
Are you suggesting a US company that shoots rockets to the moon can't be arsed to follow even a global standard? Like, who the hell else can it be doing business with if the Imperial standard from a king 200 years ago is its ride-or-die baggage?
I do specialized scientific machining and design in the US and it's all imperial. Not because it's the best but it's what's been done.
The first one was tall and skinny and toppled over after a landing leg malfunctioned. So they sent a second tall skinny probe, loaded with expensive equipment. Aaaand it fell over.
Maybe somebody should tell them about center of gravity and redundant systems.
Cool, more moon litter. Will it end up like the path to the summit of Everest, we have to place signs telling the billionaires to please clean up after themselves?
Heidi the ShonkyI'd like to share a design concept with IM given that this is their second moon topple:
KokeshI think the only one that can solve all of their problems is elon. He would fix it in few weeks. Include him in next launch, he will troubleshoot directly on the Moon. Please, someone, send that asshole to space.
roofuskitAnd he's so full of hot air he doesn't even need a suit.
He would try to smoke the moon regolith and come up with some rad ideas. Occupy Moon! Yeeeeaah
ThrashyI mean, I would too, just to see if the moon is special.
I mean look, scientists (and random bored people) for thousands of years did the same thing. Tasted things, consumed things to see what they do..
Has anyone smoked the moon yet? No. So we don’t actually know. We can speculate it does nothing, but we don’t know.
Maybe snort moon dust? Probably more practical.
marshadowHad me in the first half, ngl
The first one fell over and sank into the swamp crater.
Sooooo we built another one
That sank into a crater. So we built a third one. That burned down, fell over, and then sank into a crater. But the fourth one stayed up. And that's what you're going to get, Lad, the strongest spacecraft on all of the Moon.
But I just want to sing
TheBrideWoreCrimson- Not to leave the room... even if you come and get him.
No, no. Until I come and get him.
- Until you come and get him, we're not to enter the room.
No, no, no... etc.
veeeWhen one day we get people back on the moon, is there a chance these devices could be brought back online?
More likely salvaged as part of a permanent moon base.
This was a plot point in The Martian which was pretty neat. There was also an episode of *Futurama* which was also neat
Well, if we have boots on the moon, at that point we don't need probes like these. At that point you just drop a sensor, or whatever experiment you want directly on the surface.
I was looking at it from the perspective of all the failed probes we’ve sent and whether or not the lost costs/missions could be recouped or completed somehow.
Depends on how long it sits there, the lunar surface has a pretty wide range of temperatures that cause wear, lots of radiation and the regolith is quite abrasive. But realistically by the time something gets there that could put it back it'll probably not be worth it from anything but a historical standpoint.
x00zBreaking news, space is really really hard
Tony Bark
1984Athena (goddess of wisdom and war, strange combo).
Why?
There is no wisdom in war.
embed_meWell that's a facepalm of a faceplant 😂
You'd almost think that by now they might have learned something from the Voyager 1 and 2 power systems and not relied completely on solar power...
The biggest problem with RTGs is the extreme cost and lack of availability. Pu-238 is very expensive and at any moment, there's only tens of KG of Pu-238 available for RTG use. They're not really a reasonable choice for private industry at this time.
As true as that is, they said that it cost them hundreds of millions of dollars, and the mission was only planned to last from 10 to 14 days or so. They could have used just a piece of a waste uranium rod or something as an alternate power source for such a short-lived mission.
I mean yeah, of course that would still add to the cost and complexity, and I don't even know what all that would take, but hell if you're already into the hundreds of millions of dollars range, you ought to consider redundancy and alternate power sources.
I imagine it's more complicated than that. For example, Pu-238 only emits alpha radiation. I doubt that reactor waste only emits alpha radiation, meaning you'd have to harden the electronics for a close and potentially extreme emitter of beta/gamma radiation. I also don't know if random high grade reactor waste gets hot enough to provide meaningful amounts of energy via thermoelectric means. Alternatively, it may be that it gets too hot.
I doubt they could have simply slapped something together. The cost of developing a new RTG capable of using reactor waste would likely be a significant fraction of the budget to develop the probe itself. It might have been worth it, but I feel that it's not clear-cut.
Eh... I think they should stick to solar power. Given how much trouble they've been having, let's not give them any weapons grade isotopes...
For what it's worth, just last week, Firefly stuck the landIng on their first attempt. They're seriously killing it these days, I'm happy for them.
Solar power? On the south pole of the moon?
That would just barely work on its own, even if the thing didn't topple over.
Would it barely work, or would it always work?
If you plan to land on the pole, at a high altitude, you could potentially have direct line of sight to the sun 24/7 all year round. From the ground, the sun would appear to travel left to right along the horizon, making a full circle over the course of a month. You just need your solar panels pointed to the sides, not up.
However, if they aren't directly on the pole, they could still plan their landing to be in a location that gets sunlight for 15 earth days straight, with 0 interruption. As that might be more than the necessary time period for their experiments, that's probably perfect. And that doesn't even require being at a high elevation.
Also, being on the pole doesn't result in dimmer sunlight than on the equator like it would on earth. No atmosphere means the poles get the same completely unfiltered sunlight.
Look, the vast majority of lunar landers (and there have been quite a few) have used solar power, it's the obvious choice in space.
Nah, solar is the obvious choice in space near the sun, and by not borking it up by landing sideways in a crater on the south pole of the moon.
Very limited scope for solar power, it don't work after landing sideways in a crater on the south pole.
Edit: By the way, our next lunar eclipse is in 6 days, do you really think that thing would go uninterrupted, even if it did land correctly?
We are in space near the sun... And we have successfully used solar as far out as Jupiter.
Haha, no I didn't account for lunar eclipses, but that lasts what, 2 hours?
But yeah, not falling over definitely improves the whole mission. No argument there.
I don't think it'd matter much. On earth the poles get less light, even in summer, because the angle of the sun is low so it has to pass through more atmosphere. This isn't true on the moon, obviously. The angle will be really low on the south pole, but as long as it's in sunlight it doesn't matter where it is. There are locations on the poles of the moon that never get sunlight, but I suspect it wasn't going there.
It landed sideways like 250 meters away from the intended landing zone. Did you know the moon has way more craters than Earth?
Craters = Shadows
The thing ain't got no sunlight yo, and its laying sideways in the shade, so no power...
I'm pretty sure they didn't expect it to land sideways. Yeah, there are a lot of craters. They can be avoided. Check out how Firefly's guidance system was able to change landing locations to avoid hazards.
I don't need to check Firefly's guidance system. The Athena team should check into that though, apparently this is their second similar failure.
Send them the email, not me, I'm just a nobody.
They also used the same design of a prior craft that met the same fate. But private industry are problem solvers. 🙄
RhaedasThis could have potentially happened to Apollo 11, had Armstrong not taken over manually to steer clear of the targeted landing site with some rough areas. Maybe it would have been just leaning and not a big deal, but at the time we had no clear idea what a real landing would end up like. And I would hazard a guess that even though we've done a lot over the decades, the polar regions of the Moon are still pretty unknown.
Seems Firefly Aerospace has got this all sorted, though. Amazing feat for them last week to have a flawless landing.
Landing a fridge on those spindly little legs did seem a bit... optimistic...
I really don't understand the tall moon lander strategy... I mean, if you're going to design it with a high center of gravity, then design it to fall over... Just use two landing legs instead of four, to ensure it falls over the right way. Then you put the solar panels on the side, so that when it topples over they're facing up.
I've literally done this in Kerbal space program, it's a pretty reliable landing system if your probe is tall.
Weight == $$$
Wait, I thought Eggs == $$$
🤔
Yes, and eggs have weight.
So they couldn't use eggs as a power supply.
Therefore, the only alternative was to rely entirely on solar.
Meanwhile, they now have nuclear diamond batteries. Hell, the Voyagers have been running on aging plutonium for nearly 50 years.
You'd figure a modern expensive system like that might have a modern secondary power source, at least enough juice to run for two weeks FFS...
Who has nuclear diamond batteries? Those are a total myth drummed up to get investor money. They don't actually exist.
Sure the concept exists, in the form of betavoltaic batteries, those have been around for decades. They are tough and last dozens of years if not longer. The only problem is, they put out microwatts. You can use them in very niche applications, but those are few and far between. It's hard to convey how little power a microwatt is, it's basically nothing.
What you care about when going to space is energy density, and the proposed energy density of nuclear diamond batteries is very poor.
Rtgs are very useful for longterm missions, but are crazy expensive. They also aren't being made anymore, so getting a hold of one is hard. The weight is an issue as well, they are super heavy.
These commercial moon missions are primarily demonstrator missions. They aren't meant to last, they don't really have a goal and often don't do something useful. The idea is to show you can do it, so you can sell a product. Other people that do want to do useful stuff can then pay to get their stuff to the moon. So if the mission is over when the sun sets in two weeks time, that's perfectly fine.
'They aren't being made anymore'
Yep, I think we've identified at least part of the problem. Once humans figure out a technology that can last decades, we test it, verify it works, and then stop using it in favor of cheaper shit meant to fail as fast as a dozen eggs rot..
Meh that may be true in some ways, but not really in this case. RTGs were made using a surplus from production for nuclear bombs. As that production ramped down combined with better solar and batteries, the demand went down and it became more expensive to produce them. So not making them made sense.
An RTG is really only useful for missions that go far away from the Sun, making solar non-viable. RTGs are a pain in the neck all throughout the process, are heavy and expensive (even back in the day). The amount of electrical power an RTG delivers is also very low. This is because an RTG only gets warm, nothing more. So we put TEG (Seebeck) devices on the sides to generate electrical energy from the thermal gradient. But TEGs suck ass, they are super inefficient. For example the RTG the big Mars rovers use put out 2000W of thermal energy, but they manage to get only 110W of electrical energy out of that. So if you are near enough to the Sun, solar is the much better option.
Because for the amount of power needed they would have to halve its payload capacity if they used RTGs
Eclipses end, though. Being tipped over does not.
Quite true. Strangely, here on Earth they have smart robots that you can literally kick over sideways, and their sensors and hydraulics and stuff kick right in and set them back upright.
If you're gonna dump hundreds of millions of dollars into such a project, why not utilize all known, available, and proven technology?
Weight. That's the only actual answer.
It's extremely expensive to send weight to the moon, everything you list is more weight.
More weight but functioning vs multi-million-paperweight?
You're looking at it with hindsight. Sure it feels like spending another million $ designing, testing, and adding additional weight, along with removing weight from other parts looks like the right decision now.
Every design makes compromises, and every failure looks stupid when looking at the end result. The team had decisions to make and if they had the extra time and money, then making the existing design more robust with more testing and reliability would have been the better solution.
How would a secondary power source save it from being tipped over? That's a mission ending failure no matter how many redundant power sources you have.
Being tipped over doesn't inherently stop all of its equipment from working, I'm sure at least some of the sensors could otherwise still work, if they had power.
Even if only 10% of the sensors and equipment could still work, 10% would still be better than 0%.
True, but communication could still be a problem.
Generally this kind of probe will have a highly directional antenna that has pretty strict limits on it's aim. We would have to be very lucky for the antenna to not get damaged during the fall and end up in a position where it can still establish a connection. Even if all the science is fine, it's as good as useless if it can't communicate any results or accept commands.
Ah, but it did send data back before the battery ran down, at least enough data to confirm it fell over when it landed.
It's all about weight when going to space. It's one of the basic parts of rocket science. If you want to send 1 pound into space, you need to add gas to cover that weight, and the weight of the gas you add. Eventually you reach a point where the combined weight of the gas is more than the thrust it provides and you can't add more. Solar is light, a few hours of no power isn't a big deal over months or years of operation time, if you are confident things will come back on when there's light again.
What other power source? There is only solar and nuclear in space. And not even NASA does nuclear unless absolutely required for the mission.
We have uranium in our tap water here. As long as it remains less that 43 parts per million, they consider it 'safe'. With hundreds of millions of dollars to throw around, it can't be all that difficult to filter enough uranium out for the energy for a two week mission.
And it was a private spacecraft, not made by NASA (although it carried some of their sensors and equipment).
You don't know how nuclear power works.
Not directly, no. But my late father was a nuclear reactor cooling technician, I did learn quite a bit more than the average person.
Sure you did.
That's just private-sector efficiency taking control.
Chief O'Brien would be so disappointed. he wouldn't like to be caught without a secondary backup in a crunch.