Odysseus’ tip-over likely caused because it landed without good elevation data
It appears that the improvised switch to a NASA range finder instrument just before landing only partly worked during Odysseus’s landing attempt on the Moon, causing the spacecraft to hit the ground at too great a speed with too much laterial motion, resulting in the snapping of one leg and the lander tipping over.
Apparently, Odysseus could no longer process altitude data from the NASA instrument once it was within 15 kilometers of the surface. It had to rely on its optical cameras, a poor substitute.
By comparing imagery data frame by frame, the flight computer could determine how fast it was moving relative to the lunar surface. Knowing its initial velocity and altitude prior to initiating powered descent and using data from the inertial measurement unit (IMU) on board Odysseus, it could get a rough idea of altitude. But that only went so far. “So we’re coming down to our landing site with no altimeter,” Altemus said.
Unfortunately, as it neared the lunar surface, the lander believed it was about 100 meters higher relative to the Moon than it actually was. So instead of touching down with a vertical velocity of just 1 meter per second and no lateral movement, Odysseus was coming down three times faster and with a lateral speed of 2 meters per second.
Though the spacecraft landed upright, the high speed and sideways motion caused one leg to snap, and the spacecraft then fell over. In this sideways position Odysseus’ main solar panel could not get enough sunlight, forcing the mission to end prematurely.
A final press conference summing up the mission is scheduled for 2 pm (Eastern) today.
Was the mission a success? The failures and problems during touchdown illustrated engineering and management issues that must be addressed before the next flight. At the same time, the mission’s number one goal was to soft land on the Moon, and it did do so, even with those serious engineering problems.
More important, this flight’s first and foremost goal was an engineering test of that technology. In this sense that mission succeeded brilliantly, revealing those last technical issues.
Readers!
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In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
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It appears that the improvised switch to a NASA range finder instrument just before landing only partly worked during Odysseus’s landing attempt on the Moon, causing the spacecraft to hit the ground at too great a speed with too much laterial motion, resulting in the snapping of one leg and the lander tipping over.
Apparently, Odysseus could no longer process altitude data from the NASA instrument once it was within 15 kilometers of the surface. It had to rely on its optical cameras, a poor substitute.
By comparing imagery data frame by frame, the flight computer could determine how fast it was moving relative to the lunar surface. Knowing its initial velocity and altitude prior to initiating powered descent and using data from the inertial measurement unit (IMU) on board Odysseus, it could get a rough idea of altitude. But that only went so far. “So we’re coming down to our landing site with no altimeter,” Altemus said.
Unfortunately, as it neared the lunar surface, the lander believed it was about 100 meters higher relative to the Moon than it actually was. So instead of touching down with a vertical velocity of just 1 meter per second and no lateral movement, Odysseus was coming down three times faster and with a lateral speed of 2 meters per second.
Though the spacecraft landed upright, the high speed and sideways motion caused one leg to snap, and the spacecraft then fell over. In this sideways position Odysseus’ main solar panel could not get enough sunlight, forcing the mission to end prematurely.
A final press conference summing up the mission is scheduled for 2 pm (Eastern) today.
Was the mission a success? The failures and problems during touchdown illustrated engineering and management issues that must be addressed before the next flight. At the same time, the mission’s number one goal was to soft land on the Moon, and it did do so, even with those serious engineering problems.
More important, this flight’s first and foremost goal was an engineering test of that technology. In this sense that mission succeeded brilliantly, revealing those last technical issues.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
Okay, the NASA range finder instrument was nice, but what they really needed was Neil Armstrong at the controls, calmly and coolly guiding the craft to a soft landing.
Very odd. Its pretty flat there and the LRO digital elevation model should have got them there pretty well without an instrument. They could not store the data? They could not read their position and relate it to the model?
Steve,
It landed on a 12% slope. That is 50% steeper than a wheelchair ramp. Not flat.
Space.com reports it broke a leg.
I’m just an amateur, but this lander looks top-heavy, to me.
Just sayin’….
Do we know where the actual center-of-gravity is located?