Space is hard... Intuitive Machine's lander nearly didn't make it
Several eye-opening details were revealed at NASA's press conference last night.
An American team just soft landed a craft on the moon for the first time since Apollo 17 in 1972, 52 years ago. This is incredibly exciting news for humanity. Even more exciting is the fact that this feat was largely accomplished by private companies. NASA invested $118 million in Intuitive Machines as part of their Commercial Lunar Payload Services program. NASA also built six science experiments for the mission and provided access to their deep space network. However at the end of the day it was Intuitive Machines that built and operated the lander. SpaceX provided the boost towards the moon using their Falcon 9 rocket.
In this post I’ll discuss some incredible revelations from NASA’s press conference yesterday in Houston. The mission almost failed, but luck was on their side. Two problems effectively canceled each other out in a very fortuitous way.
Context
The past decade there has been renewed interest in the moon, with several new players looking to develop lunar capabilities (China, India, and Japan) in addition to the US and Russia. Landing on the moon is not just a matter of national pride. Firstly, the moon is a great “training ground” for developing all the capabilities needed to go to Mars. Secondly, it’s much cheaper to launch the propellant needed for Mars missions from the moon than from Earth, owing to lunar gravity being only 1/6 of Earth’s. A lunar fuel manufacturing plant and depot starts to look attractive when one considers how much fuel will be needed to transport goods to Mars in order to build a self-sustaining colony.
On August 23, 2023 India’s Chandrayaan-3 successfully landed on the moon, an incredible accomplishment, especially given the tiny budget of the Chandrayaan program (US $170 million). This followed the loss of the Chandrayaan-2 probe in 2019 when it crashed into the moon.
On August 19, 2023 Russia attempted to soft-land a craft on the moon for the first time since 1976. Their 1.2 ton craft suffered an issue when an engine couldn’t be shut down. The craft crashed into the moon at high velocity, creating a crater that was visible from orbit.
On September 6, 2023 Japan landed their SLIM probe on the moon. The craft landed upside down and sustained damage to its antenna. Still, the mission was was deemed a success and the landing was within 100 m of their target, the first ever precision lunar landing.
On January 8, 2024 the startup Astrobotics launched their Peregrine lander towards the moon, which was also funded by NASA. Unfortunately, a propellant leak developed shortly after launch, leading to the decision to terminate the mission and and direct the craft back to Earth for a controlled re-entry over the Pacific Ocean.
Revelations from yesterday’s press conference
The initial orbit of the craft wasn't right - it was too elliptical. Additional burns were needed to correct it. This was actually good because they were forced to activate their laser rangefinders to help correct their orbit.
It turned out that the laser rangefinders didn't work - they forgot to disable a safety switch before flight! At first, they thought everything was working, but then after digging deeper the next morning they realized there were errors in the telemetry. That clued them into the fact the laser rangefinders were not working.
Under normal operations the rangefinders would not have been given the command to turn on until five minutes before landing. That would not have been enough time to develop a fix!
After Intuitive Machines CEO Stephen Altemus told CTO Dr. Timothy Crain they did not have rangefinders, Altemus says “his face got absolutely white, because it was like a punch in the stomach that we were going to lose the mission.”
The failure of the rangefinders led to a "hail Mary" moment. They had to develop a makeshift laser rangefinder using an experimental NASA instrument which by a stroke of luck happened to be on board. The situation had dramatic Apollo 13 vibes but under even tighter time pressure.
A team of over thirty engineers worked a "48 hour day" (!) to work through all the challenges.
They had to abort their initial landing and orbit one more time to give time to update the software. Guidance and navigation had to be shut down for a short period of time in order to do the update. As a result of these changes in the mission they had to disable EagleCam, a special camera that was going to deploy to film the landing.
They were running low on helium which was a cause for concern. (I believe this is used to pressurize tanks??)
They hit the lunar surface at 6 mph vertically instead of 2-4 mph and with a sideways velocity of 2 mph instead of 0 mph.
As a result the vehicle tipped over, possibly because they tripped on a rock, or because a leg got caught and broke (they don't know yet).
They had difficulty with communications the whole time. Because they were using fixed antennae, they had to lose signal during the roll maneuver during descent. After landing, communications got even harder because one antenna is aimed at the surface of the moon. Only sufficiently large radio dishes around the world can communicate with it so they do not have 24 hour communications.
Initially they thought they were upright, but they later realized the data they were looking at was "stale". It wasn't until several hours later that they figured out they were sideways by closely inspecting the readouts from the tank gauges.
As a last note, I found it interesting that the mission will only last two weeks since the lithium batteries on board cannot survive the cold of lunar night.
At the end of the day, they soft landed with all instruments and payloads operational and they expect to get all of the data they wanted. This is an incredible accomplishment!
Still, the details of what transpired are a sobering reminder that space is hard and that succeeding in space requires careful and concerted effort by humanity’s best engineers.
"They hit surface at 6 mph vertically instead of 2-4 mph and with a sideways velocity of 2 mph instead of 0 mph.... As a result the vehicle tipped over, possibly because they tripped on a rock, or because a leg got caught and broke (they don't know yet)."
-- Space is hard? Well yes, but it seems that SpaceX did all the hard work by launching Intuitive Machine's lander into orbit and on its way to the Moon.
Seems like the typical software design issues many projects (from the vending machines at the library where I often go that take my money and dispense no product) to "automation features" of appliances these days -- good intentions but poor thinking about what needs to go into a design and even poorer code in the implementations.
If they effectively crashed because they could not remove like 2mph velocity in both dimensions (I'm sure 4mph vertically would have been fine) .... come on.... this has nothing to do with space being hard.... but everything to do with the typical lousy software engineer out there.
Nice summation of this exciting space mission. If space wasn't hard, a lot more organizations would be operating on the moon right now. Hope we get all the data from this mission that we can. Better luck next time.