Japan's precision moon lander has hit its target, but appears to be upside-down
phys.org
phys.org
That juxtaposition is just uncanny. This japanese mission is surprisingly kerbal.
https://en.wikipedia.org/wiki/Smart_Lander_for_Investigating...
https://www.upi.com/Science_News/2024/01/25/Japan-SLIM-landi...
After ejected they both circle around and look for the mothership autonomously, and in this instance the wheeled LEV-2 rover found what it believes to be the ship and the hopper LEV-1 rover relayed the thumbnail back to Earth via direct downlink.
It was meant to use a rather odd "two-step" landing procedure where it first touches down on the lunar surface on it's rear/primary landing gear, then pivots forward/falls under gravity to also touch down on the front/secondary landing gear.
Presumably this landing procedure was simulated under lunar gravity, but it seems there are multiple potential failure modes:
1) After rear "leg" touchdown, over-rotate forwards over front leg (ending up on back), OR
2) After front "leg" touchdown, bounce/recoil backwards off front leg, flipping onto back, OR
3) Front landing gear hits rock on one side (left or right), thereby flipping it sideways onto back
The whole procedure seems to rely not only on having correctly simulated under lunar gravity (and with correctly simulated stiffness of the vehicle) to avoid scenarios 1) & 2) (which would be different under earth gravity), but also the softness of the landing site being uniform and as simulated - otherwise if landing site surface was harder (rock) or softer than expected, or uneven, then this type of pivot and bounce/not landing would not go as planned.
NASA seems to have done a better job in designing fool-proof landing mechanisms, from the bouncing ball of the first mars rover, to the sky-crane landing of the latest one (which appears over-complicated, but no doubt was chosen at least in part because it is in fact more predictable than the alternatives).
I wouldn't read too much into that choice.
More likely the velocity was a tad too high.
That being said I perfectly see how sub-ms automated command could make what I said wrong.
That's why I was never comfortable stopping in rollerskates or ice stakes.
Also I've said before and will say it again, the moon is not far away. Unlike Mars and other celestial bodies where we have to time launches around orbital positions, gravitational slingshots and such, the moon is really close by, and we should be lofting stuff onto it on a monthly basis.
> One of the lander's main engines lost thrust about 50 meters (54 yards) above the moon surface, causing a harder landing than planned.
When I first heard that they might have landed upside down, a part of me felt a pang of indignation and condescension, for about ten seconds. But I kept my mouth shut and realized these things are hard and something I didn't think of in the ten seconds as an armchair lander-designer might have occurred.
I found the tone of your comment pretty condescending, tbh. Hot landing is hot landing, and you're just speculating as a layman without any insight into their design and decision-making process. "Not simulating lunary gravity correctly." Like c'mon, that's just an insult to their intelligence.
Not really, it's only been used for a few Mars missions, and not recently. For lunar missions you don't have the benefit of aerobraking, so you have to use so much fuel to slow down already, the math doesn't work out to use airbags at the last step.
The purpose of this landing design was explicitly to allow landing in areas that wouldn't previously be considered acceptable: slopes.
I get being really, really proud of what you accomplished here, but...perfect? Really? You can't think of anything that maybe could have gone better?
I know it's a much more sophisticated problem than this, but my inner child thinks they just forgot "the planet(oid) has to be 'down' on both ends of the trajectory."
Probably, almost certainly, that isn’t what happened. But it could!
Chuck Yeager
But the passenger payloads deployed correctly, so we'll count that as walking away.
OTOH, in defense of the PM, the lander showed exceptional robustness against loss of an engine, so he'd have a reason to be proud of an explosionless landing.
It was just the juxtaposition of "perfect" with the picture of the thing upsidedown that made me laugh. "Near-perfect" I'll happily grant. Same with "impressive as all get-out." But "perfect" made me chuckle.
S rank! Play next time for SSS!
While most previous probes have used landing zones about 10 kilometers (six miles) wide, SLIM was aiming at a target of just 100 meters (330 feet). Improved accuracy would give scientists access to more of the moon, since probes could be placed nearer to obstacles.
The context of the comment in the article referred to the “pinpoint landing” aspect of the landing. They narrowed down the landing range from 10,000m (10k) to 100m… two orders of magnitude.
From the the article, emphasis mine:
> For the pinpoint landing, Sakai said, he would give SLIM a "perfect score."
> "We demonstrated that we can land where we want," Sakai said. "We opened a door to a new era."
I don’t know if this comment was made in English or Japanese, but I could see how a very specific comment about the pinpoint aspect of the landing in Japanese could be vague when translated into English.
I don’t think anyone is disillusioned enough to think the overall landing was perfect.
> いろんな意味で新しい扉が開き、今後、これまでできなかったようなミッションができるようになるのでは。そこが一番の意義ではないか
I'm far from a translator... but it is not "We opened a door" but "A door is open to do missions that were not possible before". And he says that might be the most important takeaway from this project.
https://news.yahoo.co.jp/articles/08a8bfdd7a41486140a97a8570...
You're being overly literal. Omitting the subject is normal in Japanese; translating that to a passive-voiced sentence in English is usually misleading.
が makes the subject the door, not JAXA. Plus it would be very uncharacteristic of a Japanese person in that position making such a bold claim. It goes against Japanese society norms.
Translation for those wondering.
[0] https://en.wikipedia.org/wiki/Apollo_12#Lunar_orbit_and_Moon...
On the context of the "perfect score", they initially gave themselves a 60 out of 100 score during their first press conference after the landing, and today a member of the audience explicitely asked them to revise that score knowing what we know now.
The speaker made the point that achieving that much of precision is just ground breaking and will completely change how we frame the "where do we land" question from now on,so giving it a perfect score is I think legit.
The problem may have been in their metrics. The KPI should have been a successful landing for the full range of 'successful'.
But that all depends on whether, "land upright and measure things with the expensive instruments we sent it with" was originally included as a primary objective and whether they've just moved the goal posts to minimize the appearance of the failure.
My opinion is that it should be: "Japan's space agency said Thursday that its first lunar mission hit the tiny patch of the moon's surface it was aiming for. It was a successful demonstration of its pinpoint landing system although the probe appears to be lying upside-down."
> But after the landing mishap, the craft's solar panels wound up facing the wrong direction, and it cannot generate power. Officials said there is still hope the probe will be able to recharge when the moon enters its daytime in the coming days.
Robotic Moon Landing Missions in 21st Century
Chang'e 3(2013)
Chang'e 4(2019)
Beresheet(2019)
Chandrayaan 2(2019)
Chang'e 5(2020)
Omotenashi(2022)
Hakuto-R(2023)
Luna-25(2023)
Chandrayaan-3(2023)
Peregrine M1(2024) [1]
https://twitter.com/IndianTechGuide/status/17446149885918046... 2
It’s vindicating to learn that even the pros struggle to land on a particular spot and end up knocking over their moon lander anyway.
Of course, their environment is much more detailed than KSP and doesn’t have a quick-save button.
Space is hard.
See this X thread: https://twitter.com/MADOguchimoto/status/1750415013343596786
The artist has anthropomorphized the lander - along with the "Sora Q" probe coming to document its misfortune.
That’s an incredible result.
Life imitates art. Astonishing.
Undoubtedly, I'll forget all this by tomorrow morning and remember Asia :-)
Is Moon's gravity strong enough to cause damage to solar panels or antennas if probe tips?
1: https://www.isas.jaxa.jp/home/slim/SLIM/assets/img/SLIM_exp....
And, after a hard landing, the RCS system may be damaged - so attempting to use it might result in a RUD event. Or the needed thrusters might be extremely close to the lunar surface (which could direct thruster exhaust and lunar soil back at the lander). Or the RCS might have been given a one-way ticket into a Safe Mode (to minimize potential issues) when the lander touched down. Or...
'Ha, they told me a million times exactly _where_ I should land, but they never specified _how_ I should land'
https://forum.kerbalspaceprogram.com/topic/79115-where-is-th...
"Mun or Bust!"
For model names, it’s more possible that it could be in Japanese, but even then I think it’s rare. Even outside of the realm of global industries like cars you’ll find English words and phrases being used to brand everyday local products all over the place. Japan is far more full of English writing than the Anglosphere is of Japanese…or any other language. When actually talking about these products, though, it’ll usually be written in Japanese (not least because most people in Japan aren’t confident enough in their English ability to use/remember those words and their often unpredictable spellings).