Picture the time: it’s 1999, and we’re in a new era of peace. We’re between major wars, communism has been cornered in small pockets, the economy’s doing fine, the Berlin Wall fell some time ago, and the hole in the Ozone Layer at least isn’t getting any worse. And 9/11 hasn’t happened yet.
It really felt like this was the era we’d get to Star Trek levels of technological advancement! The future was bright and ready for humanity to take the next big leap forward.
Enter: NASA. We’d landed on the moon, we’d launched satellites, and we’d sent landers to Mars. Now, we were going to send more, with better tech and better tools. It was still kind of a flex of US propulsion systems, but it was more about the learning we’d get from it.
Mars is a popular target for many reasons. The primary one is the lack of acid clouds and hellfire found on Venus – landers sent there don’t last very long at all. Besides that, Mars is more likely to support life. It has some amount of frozen water on the surface, a thin atmosphere with weather, and some movement in the mantle. If there’s anywhere people could live besides Earth in the solar system, it’s probably going to be Mars. Moon bases are a cool idea, but the moon doesn’t have nearly as much water as Mars does, and no atmosphere is a big downgrade from thin atmosphere. Not to mention things like gravity – astronauts who spend a lot of time in space come back with weaker bones and elongated spines. The moon will make you taller than Mars will, but you’ll also get weaker, faster.
The Mission
The orbiter being sent this time was meant to analyze the atmosphere of Mars, safely, from a high orbit. The orbiter was assembled by both NASA and outside contractors who could make the specialized equipment, and nothing had gone wrong during the building process – yet. What had actually happened was a piece of software made by Lockheed Martin was delivering results in the wrong units. It was using the American pound-seconds, instead of Newton-seconds like the rest of the craft.
Lockheed had been sending their data like this the entire time. The NASA team assembling the orbiter was aware of this and was translating their data into the correct format, but they hadn’t yet programmed this into the craft. Final assembly came and went, and officially, no issues were reported. Unofficially, a couple of software engineers on the project had discovered an issue with data sent to the orbiter during tests, but – allegedly – didn’t fill the forms out correctly, so the problem was dismissed.
The orbiter is launched into space. Several months pass, and all is going according to plan. Everything at this moment is relying on other, in-house software without the conversion problem, so the launch goes fine, the thing’s on the right trajectory, etc. etc. When the orbiter is sent out on its own, however, engineers discover a problem they can’t fix: the thing’s not where they thought it would be. It’s very close to Mars. It’s at the lowest it can be and still survive, so engineers didn’t panic right then and there. They don’t know about the software bug. They began corrective maneuvers, but lost contact with the orbiter as it disappeared behind Mars. Anxiously, NASA waited for it to reappear, but it never did. They’d lost a project.
The silence in that room must have been deafening.
The AfterMath
Wikipedia calls its death “unintentionally deorbited” which is kind of funny. NASA accepted full blame for the project’s failure, and essentially said their quality control hadn’t been up to snuff. Errors detected when the orbiter was still on the ground went ignored, and Lockheed was supposed to be converting its software to metric before it sent it to NASA (allegedly – Simspace mentions this, but NASA’s release does not).
Ultimately, the unit the contractor’s software was using was 4.45 times greater than anything the rest of the craft was using. The software reads some measurement it’s getting from it’s thrusters vs. its real position, and panics, because it can tell it’s not where it’s supposed to be. It gets closer and closer to the planet, and all the while it’s still panicking because now it’s not the right speed or at the right place. Eventually, Mars consumes it, like it consumes everything we send it.
All because the unit measure was supposed to be tested at the contractor facility.
Positives
To quote Josh Bazell, “In metric, one milliliter of water occupies one cubic centimeter, weighs one gram, and requires one calorie of energy to heat up by one degree centigrade—which is 1 percent of the difference between its freezing point and its boiling point. An amount of hydrogen weighing the same amount has exactly one mole of atoms in it. Whereas in the American system, the answer to ‘How much energy does it take to boil a room-temperature gallon of water?’ is ‘go [CENSORED] yourself’ because you can’t directly relate any of those quantities.”
NASA had been working in a strange hybrid system that made data translation ugly and added steps to sharing valuable data with other nations. As seen in this Mars mission, anything that adds steps also adds room for error. Spaceflight calculations don’t need weird, arbitrary numbers to clutter up the already-complicated systems in place.
Between this mission’s failure and other nations’ requests, NASA announced a plan to switch entirely to metric in 2007. As they say on their website, standardizing units also means that we’ll be easier to cooperate with in the future! And there’s less chance of misunderstandings between co-op projects on other planets. Imagine getting to Mars and realizing the US rover’s 3 miles away instead of 3 kilometers! Or wasting valuable weight on fuel because US gallons are larger than metric liters.
It feels like a miracle that this was the first time an issue like this had ruined a mission!
Sources:
https://www.britannica.com/science/calorie
https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbiter-metric/
https://science.nasa.gov/science-news/science-at-nasa/2007/08jan_metricmoon
https://www.nationalgeographic.com/science/2019/12/first-active-fault-system-found-mars2/
https://solarsystem.nasa.gov/missions/mars-climate-orbiter/in-depth/
