Skip navigation

Tag Archives: Mars Climate Observer

That would’ve made an arresting headline, wouldn’t it? Well, guess what, Star Wars fans – it really happened. The imperial units involved weren’t stormtroopers, though; they were things like inches, feet, and pounds. It’s hard to believe, but the good folks at NASA lost the Mars Climate Observer (MCO) – a $300 million mission – in 1999 due to a failure to convert to metric units. Here’s what the Mishap Investigation Board (what a delightful understatement, by the way – to call such a screw-up a “mishap”) had to say:

The MCO MIB has determined that the root cause for the loss of the MCO
spacecraft was the failure to use metric units in the coding of a ground
software file, Small Forces, used in trajectory models. Specifically, thruster
performance data in English units instead of metric units was used in the
software application code titled SM_FORCES (small forces). A file called Angular
Momentum Desaturation (AMD) contained the output data from the
SM_FORCES software. The data in the AMD file was required to be in metric
units per existing software interface documentation, and the trajectory modelers
assumed the data was provided in metric units per the requirements.

Besides being a redeeming story that you can triumphantly relate to the old math teacher who castigated you for every careless mistake, this incident does also evoke some worrying thoughts. Yes, we all make mistakes, but most of us aren’t in a position to cause a spacecraft to careen out of orbit to crash into a planetary surface. A lot of scientists, though, have access to a lot of things that – well, are capable of creating quite a big bang. What if someone had screwed up the insertion of a satellite into geostationary orbit around the Earth, for instance?

I’m not the sort who likes to foment panic about the dangers of rapidly advancing technology, and I suppose we’ve been pretty lucky so far. The LHC did not create a black whole that swallowed up the Earth, the National Ignition Facility in California did not set the atmosphere ablaze, and no nuclear power plant has turned out to be nuclear bomb (although I suppose the government of Iran may want to change that). But it is interesting to note that as our knowledge expands, our inimitable sense of curiosity becomes ever more potentially dangerous. In Kurt Vonnegut’s novel Slaughterhouse Five, a race of extraterrestrials called Tralfamadorians cause the extinction of the universe while experimenting with new energy sources. I wonder if a similar fate awaits us.