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Recent Moon landings
- Thread starter lpetrich
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lpetrich
Contributor
Smart Lander for Investigating Moon - SLIM - landed on the Moon recently, tipping over but releasing two rovers.- Japan Achieves a Soft Lunar Landing, but Its Life on the Moon May Be Short - The New York Times
- Japan Explains How It Made an Upside-Down Moon Landing - The New York Times - "The SLIM spacecraft survived its trip to the surface, but ended up pointing in a direction that now limits the duration of its mission."
- Japan's SLIM moon lander photographed on the lunar surface — on its nose (image) | Space
- SLIM, Japan’s precision lunar lander | The Planetary Society
- Japan’s SLIM achieved pinpoint moon landing with just one working engine - SpaceNews
- Japan's powered-down "Moon Sniper" lunar lander achieves major goals, despite engine malfunction - CBS News
- Stricken Japanese Moon mission landed on its nose
- Japan’s ‘moon sniper’ probe made incredibly accurate landing, but is now upside down | The moon | The Guardian - "Slim probe landed metres rather than kilometres from its target, but a rocket malfunction has left it in an undignified position"
- SLIM Lander Powers Down for Long Lunar Night; JAXA Releases New Batch of Moon Snapshots - The Japan News
- Japan's moon probe SLIM in dormant state with solar power generation unavailable: JAXA - Chinadaily.com.cn
- Japan's SLIM moon lander may be dead for good as freezing lunar night sets in | Live Science
Local daytime will start again on February 15.
I can't find out much on the two rovers, but they seem to be functional. Will they also survive the lunar night?
lpetrich
Contributor
Lists of spacecraft and List of missions to the Moon and List of lunar probes and List of landings on extraterrestrial bodies and List of artificial objects on the Moon and List of active Solar System probes- Astrobotic - the maker of the Peregrine lander
- Lunar Landers | Astrobotic Technology - Peregrine and a larger one, Griffin
- Moon Rovers | Astrobotic Technology - including a very small one, CubeRover, designed much like the cubesat platform for small satellites
- Future Missions and Technology | Astrobotic Technology
Japan, India and Russia Race to Land, or Crash, on the Moon - The New York Times
Nova-C - an upcoming lunar lander made by Intuitive Machines. Its first launch will be early this year, its second one in midyear, and its third one late this year.Another one is
Chang'e 6, likely in May of this year. Firefly Aerospace will send the Blue Ghost lander to the Moon late this year. VIPER (rover) will be sent to the Moon in Astrobotics's Griffin lander late this year.
lpetrich
Contributor
Blastoff! SpaceX launches Intuitive Machines 'Odysseus' lander to the moon - YouTube on February 15
Intuitive Machines Nova-C noting IM-1 the spacecraft that that rocket sent to the Moon.
That spacecraft went into low lunar orbit on February 21, and then landed near the Moon's south pole on February 22. However, it caught on something and it tipped over when it landed, and it is now on its side. But it is otherwise functional.
Another recent lunar lander tipped over, and it also survived. Japan's SLIM moon probe unexpectedly survives lunar night | Reuters
Intuitive Machines Nova-C noting IM-1 the spacecraft that that rocket sent to the Moon.That spacecraft went into low lunar orbit on February 21, and then landed near the Moon's south pole on February 22. However, it caught on something and it tipped over when it landed, and it is now on its side. But it is otherwise functional.
Another recent lunar lander tipped over, and it also survived. Japan's SLIM moon probe unexpectedly survives lunar night | Reuters
Shadowy Man
Contributor
The top-heavy intuitive machines lander was moving laterally around 2mph when it hit the ground downwards at 6mph on a terrain tilted by about 12 degrees. It had to rely on an experimental LiDAR system when their own system proved to not be operable because someone forgot to disable the laser safety feature before flight.Blastoff! SpaceX launches Intuitive Machines 'Odysseus' lander to the moon - YouTube on February 15
That spacecraft went into low lunar orbit on February 21, and then landed near the Moon's south pole on February 22. However, it caught on something and it tipped over when it landed, and it is now on its side. But it is otherwise functional.
Another recent lunar lander tipped over, and it also survived. Japan's SLIM moon probe unexpectedly survives lunar night | Reuters
Sigh… but they still technically landed, and very close to where they wanted, being able to communicate with the lander through lower gain antennae (high gain pointed the wrong way because of the sideways orientation).
DBT
Contributor
Should search, but I wonder what reason there is for designing the lander to be top heavy and prone to toppling?
bilby
Fair dinkum thinkum
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They should have put Fritz van Noon on the job.
https://en.wikipedia.org/wiki/Unorthodox_Engineers
Get Away from Getawehi
Shadowy Man
Contributor
I believe it had to do with the way the fuel consumption would affect the center of mass, but I’m sure there’s a longer answer out there.
Had they come straight down instead of laterally it would have been less likely to topple, so they’ll need to understand what led to the trajectory they had.
But it certainly does seem to suggest potential redesigns.
thebeave
Contributor
The top-heavy intuitive machines lander was moving laterally around 2mph when it hit the ground downwards at 6mph on a terrain tilted by about 12 degrees. It had to rely on an experimental LiDAR system when their own system proved to not be operable because someone forgot to disable the laser safety feature before flight.Blastoff! SpaceX launches Intuitive Machines 'Odysseus' lander to the moon - YouTube on February 15
That spacecraft went into low lunar orbit on February 21, and then landed near the Moon's south pole on February 22. However, it caught on something and it tipped over when it landed, and it is now on its side. But it is otherwise functional.
Another recent lunar lander tipped over, and it also survived. Japan's SLIM moon probe unexpectedly survives lunar night | Reuters
Sigh… but they still technically landed, and very close to where they wanted, being able to communicate with the lander through lower gain antennae (high gain pointed the wrong way because of the sideways orientation).
How that never made it into the pre-launch check list is astounding. I used to be an engineer on missile development programs for a major defense contractor and all the engineers were nervous and edgy right before and after a launch, due to the nagging feeling that a multi-million dollar failure could be linked to some boneheaded thing you did or didn't do. I can't imagine how awful the person who was liable for that mistake must feel.
Shadowy Man
Contributor
A video I watched yesterday said they skipped certain prelaunch tests to save time and money.The top-heavy intuitive machines lander was moving laterally around 2mph when it hit the ground downwards at 6mph on a terrain tilted by about 12 degrees. It had to rely on an experimental LiDAR system when their own system proved to not be operable because someone forgot to disable the laser safety feature before flight.Blastoff! SpaceX launches Intuitive Machines 'Odysseus' lander to the moon - YouTube on February 15
That spacecraft went into low lunar orbit on February 21, and then landed near the Moon's south pole on February 22. However, it caught on something and it tipped over when it landed, and it is now on its side. But it is otherwise functional.
Another recent lunar lander tipped over, and it also survived. Japan's SLIM moon probe unexpectedly survives lunar night | Reuters
Sigh… but they still technically landed, and very close to where they wanted, being able to communicate with the lander through lower gain antennae (high gain pointed the wrong way because of the sideways orientation).
That’s how.
And in fact, had they not entered a slightly elliptical orbit first and decided to check on their orbital height with their laser system they would not have known it wasn’t working until during the final descent and would have crashed. They got lucky to find out it wasn’t working and frantically patched in the experimental nasa lidar system.
thebeave
Contributor
A video I watched yesterday said they skipped certain prelaunch tests to save time and money.The top-heavy intuitive machines lander was moving laterally around 2mph when it hit the ground downwards at 6mph on a terrain tilted by about 12 degrees. It had to rely on an experimental LiDAR system when their own system proved to not be operable because someone forgot to disable the laser safety feature before flight.Blastoff! SpaceX launches Intuitive Machines 'Odysseus' lander to the moon - YouTube on February 15
That spacecraft went into low lunar orbit on February 21, and then landed near the Moon's south pole on February 22. However, it caught on something and it tipped over when it landed, and it is now on its side. But it is otherwise functional.
Another recent lunar lander tipped over, and it also survived. Japan's SLIM moon probe unexpectedly survives lunar night | Reuters
Sigh… but they still technically landed, and very close to where they wanted, being able to communicate with the lander through lower gain antennae (high gain pointed the wrong way because of the sideways orientation).
That’s how.
I can believe it. Probably a decision by some clueless, non-technical manager.If you happen to have that video handy, I would love to see it, but if its long gone, no problem.
Shadowy Man
Contributor
A video I watched yesterday said they skipped certain prelaunch tests to save time and money.The top-heavy intuitive machines lander was moving laterally around 2mph when it hit the ground downwards at 6mph on a terrain tilted by about 12 degrees. It had to rely on an experimental LiDAR system when their own system proved to not be operable because someone forgot to disable the laser safety feature before flight.Blastoff! SpaceX launches Intuitive Machines 'Odysseus' lander to the moon - YouTube on February 15
That spacecraft went into low lunar orbit on February 21, and then landed near the Moon's south pole on February 22. However, it caught on something and it tipped over when it landed, and it is now on its side. But it is otherwise functional.
Another recent lunar lander tipped over, and it also survived. Japan's SLIM moon probe unexpectedly survives lunar night | Reuters
Sigh… but they still technically landed, and very close to where they wanted, being able to communicate with the lander through lower gain antennae (high gain pointed the wrong way because of the sideways orientation).
That’s how.
If you happen to have that video handy, I would love to see it, but if its long gone, no problem.
thebeave
Contributor
That was interesting..thanks for sharing. Despite it being an embarrassing screw up at prelaunch (
), it actually was pretty impressive that they were able to send a software patch to the lander during lunar orbit and get it to at least make it to the surface (albeit crippled). So, 
for that.
), it actually was pretty impressive that they were able to send a software patch to the lander during lunar orbit and get it to at least make it to the surface (albeit crippled). So, for that.
Shadowy Man
Contributor
Yeah. I saw an interview that stated the process they undertook in about an hour and a half would have taken a month to do had they followed standard software development and test procedures prelaunch. That they were able to patch in a system not designed to work with their lander in such a short time and hit their target within about 1.5km or so is quite a feat.That was interesting..thanks for sharing. Despite it being an embarrassing screw up at prelaunch (
Shadowy Man
Contributor
Even more information:
Yikes!
Yikes!
KSP player here: It's hard not to. Short and squat is far easier to deal with in space--but short and squat is a big problem in getting through the atmosphere. And KSP physics are far more forgiving as you don't need as high a propellant fraction in the stock game. And fuel flow is much more forgiving--pipes carry infinite fuel without regard for gravity. Adding some extra boosters to get an abomination into space isn't a big deal.
Straight down will cost you extra fuel, you do not want to kill your horizontal velocity any earlier than you have to. If you're moving at less than orbital velocity you will be accelerating towards the body below you and that is undesirable. It's called gravity loss. You minimize it by flying at orbital speed for as much of the flight as possible. Earth rockets actually tip late because atmosphere loss from tipping at the "ideal" point costs you more than the gravity loss you're avoiding. On an airless body you tip as soon as possible on takeoff, you straighten out as late as possible on landing. The exact tip depends on your thrust to weight ratio and how much control authority you have.
They had to kludge the landing because it flew with a remove-before-flight safety pin still installed, didn't get it perfect.
Those remove-before-flight pins don't fly and thus aren't subject to weight limits. I'm surprised they don't go with a system of putting some sort of transmitter on them as a cross-check.
On the other hand, I tend to keep getting surprised at how manual so many things are handled. I'm thinking of the failure of the first Ariane V launcher. They used some code from the Ariane IV, but it was wired to a new sensor--oops, the new sensor could return a higher range of values than the old one. In it's normal operating mode this was of absolutely no concern, it returned the same actual values. It was meant for precise measurements of where the rocket was on the pad, needed for on-the-fly computation of the flight profile if it didn't go off at the originally scheduled launch second--completely moot once you light the engines.
However, did they have some sort of automatic handling of this? No--the program simply continued to run for many seconds past the scheduled launch, giving the operators enough time to extend it if there was a hold. This meant that the program continued to operate while in flight. The inputs became garbage and the outputs were thus also garbage--but since nobody wanted those outputs any more it didn't matter. That is, until the new sensor could return bigger garbage than the logic could handle. Divide overflow--with no error trap as that was never supposed to occur. Primary guidance computer locked up, the backup took over--same garbage, same code, same result. While there wasn't much thrust vectoring there was a bit--and it locked hard over. The rocket couldn't handle the turn, broke and then suicided in response to the break.
Shadowy Man
Contributor
By “straight down” I was referring to the final moments. They hit the ground moving at an unplanned 2mph horizontal speed. The plan was for 0mph horizontal speed at the time of touchdown.
The second video I posted suggested that they weren’t able to successfully use the NASA lidar system because they couldn’t process the information in real time, even after patching the software. So they were likely flying on rate sensors or other hardware and thus did not have accurate enough information for the navigation system to properly stick the landing.
Which doesn't change the basic issue. Killing your horizontal velocity before you have to costs you fuel. The optimum course has your rocket only reaching no horizontal speed/entirely vertical orientation at touchdown. There is also the issue that control authority always costs, you don't put more of it than you need. (Note: KSP is a horrible model in this regard, control authority is way, way overdone for the sake of gameplay.)