Odysseus Freezing? Fuggedaboutit!

The situation with Intuitive Machines IM-1 lander Odysseus - Odie - continues to change at a rapid rate.  Just two days ago, Monday evening as I type, there was talk that if something didn't change within hours, Odie's batteries would be depleted and the lander would freeze to death in the cold lunar night, just eight days away.  Today that dire future is completely reversed.  Not only is Odie expected to operate until night fall, they're planning to see if it wakes up in two weeks (and a couple of days) like JAXA's SLIM did.  

The story of getting from there to here is a tribute to determination, hard work, and refusing to give up from the crew of a young company flying its first space mission. 

An important backup story is from yesterday in Ars Technica, a long but a fascinating read.  Titled, "It turns out that Odysseus landed on the Moon without any altimetry data" it talks about the many issues the probe went through from launch to its first couple of days on the moon.  The missing altimetry data goes back to the story posted about on Friday, explaining how they realized someone hadn't removed a safety on their laser altimeters just before they were to activate them for landing, and used a NASA payload for that information.  That wasn't completely seamless. 

While this software patch mostly worked, Altemus said Tuesday that the flight computer onboard Odysseus was unable to process data from the NASA payload in real time. Therefore, the last accurate altitude reading the lander received came when it was 15 kilometers above the lunar surface—and still more than 12 minutes from touchdown.

That left the spacecraft, which was flying autonomously, to rely on its optical navigation cameras. 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.

That meant that as the lander approached the surface, the landing system "thought" it was 100 meters higher above the surface than it actually was. Because of that, instead of touching down with a vertical velocity of just 1 meter per second and no lateral movement, Odie was coming down at 3m/sec with a lateral speed of 2 m/sec.  That led to breaking one of the lander's legs. 

In this screen capture from this video, you can see the leg on the left is broken and doesn't look like the one on the right.  In this photo, the engine is still firing and keeping Odie vertical.  Moments after the engine was cut, it tipped over, taking about two seconds to come to rest.

Eric Berger noted:

Odysseus is a beastly machine, and the team flying it isn't shabby, either. They have certainly busted their asses. The offices in south Houston were littered with the remains of junk food, coffee, and other elixirs of long nights and wracked brains. It's all been a whirlwind, no doubt. Next to a bag of tortilla chips, there was a bottle of Ibuprofen.

Among the problems they've found ways around was that when the lander tipped over, the gain antenna that had been planned to send data back to Earth wasn't pointed at Earth.  When they tried to transmit, some of the signal hit the moon's surface reflected back up and created an interfering signal - multipath.  They figured out a way to add a signal that helped them separate the desired from interfering signals.  That left them with a weak signal and the only thing that can help that is a really big receiving antenna.  They were able to get access to NASA's Deep Space Network in Australia, to get a good angle on the lunar south pole.  Intuitive Machines has opted to run customers' payloads and download their data as much as possible.  They also downloaded this picture of Odie itself.

The lander fell on its side, with a helium tank or radio shelf contacting the Moon. This protrusion, combined with the 12-degree slope of the terrain, means that Odysseus is now gently leaning on the lunar surface at about a 30-degree angle.  Image credit: Intuitive Machines.  The dark stripe around the 1/3 point vertically in the picture, and just below the copper colored shape, is a nearby crater in shadow.

NASA and IM teamed up for another press conference today that runs just over 90 minutes. Lots of good information in there. This is where I heard the IM people talking about seeing if Odie wakes up  perhaps a day or two after lunar sunrise.  Ars Technica ran another article today, "That moment when you land on the Moon, break a leg, and are about to topple over."   

Intuitive Machines says they've downloaded about 50 megabytes of data, and that every paying customer's payload has worked.  Five of the six NASA payloads are working.  Only the one intended to take data on the interaction of Odie's engine exhaust and the lunar landscape appears to have been damaged.  Despite coming to rest at that 30 degree angle they're calling it an absolute success, and are talking of working on their next missions.