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Mars Global Surveyor Died from Single Bad Command
wattsup writes "The LA Times reports that a single wrong command sent to the wrong computer address caused a cascade of events that led to the loss of the Mars Global Surveyor spacecraft last November. The command was an orientation instruction for the spacecraft's main communications antenna. The mistake caused a problem with the positioning of the solar power panels, which in turned caused one of the batteries to overheat, shutting down the solar power system and draining the batteries some 12 hours later. 'The review panel found the management team followed existing procedures in dealing with the problem, but those procedures were inadequate to catch the errors that occurred. The review also said the spacecraft's onboard fault-protection system failed to respond correctly to the errors. Instead of protecting the spacecraft, the programmed response made it worse.'"
Not the error itself, but the fact NASA was able to figure out what happened in such detail, when the spacecraft it happened to is not giving any diagnostic information and cannot be examined directly.
TFA:
MGS was well into bonus time in the sense that the original goals had been reached. The project was running on a reduced budget and this made a mistake inevitable. I can't help thinking that at a higher level this was considered to be a good thing. When you have new missions to run and a fixed budget to run them on you want your old missions to stop so that you can draw a line under it and go on to the next thing.
The last thing management want is to have to decide to shut the spacecraft down because they don't have the budget for operations on the ground. Reducing the budget is a way of inducing the shutdown.
http://michaelsmith.id.au
They don't get to build the best damn space probe they can build, they get to build the best damn space probe they can build for $X. Thermal management isn't easy; controlling orientation allows them to spend money on the stuff they are interested in, rather than insulation and shielding.
Nerd rage is the funniest rage.
There are an awful lot of posts here that disparage the people who have built and operated this system. To me it looked very much like the explanation for an aircraft accident. The easy failure modes are all known, so the really hard ones are left. In aircraft accidents, and it seems space accidents now too, a fatal result is generally the result of a number of seemingly disparate factors including system states, environmental state, and human impressions of what is going on.
In one major aircraft accident I know a lot about, the (Airbus) jet crashed in part because it ended up being a tug of war between a human pilot and a robot autopilot that should have been disengaged, causing and up and down roller coaster ride. There were lots of other distracting things that were maybe wrong or maybe not, but a key part was the difficulty in knowing what state the machine was in.
It was a similar situation with this accident, it seems, and though the misuse of metric units caused another recent accident it appears that these incidents have elements in common. They are also made more probable it strikes me by funding pressures and also in the way that operating these systems involves radical commands while the systems also lack enough power to be self-aware enough to preserve themselves.
I am not going to do any more guessing because the people involved can probably figure it out themselves, and it seems that these combined factor accidents at least are not costing human lives, while they are adding to knowledge about how not to make the accident the next time.
In that regard my hope is that some of the money being spent on Mars can be used to improve autonomous robotic systems to reduce accidents both on Mars and on Earth.