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ESA: European Mars Lander Crash Caused By 1-Second Glitch (space.com)
An anonymous reader quotes a report from Space.com: The European Space Agency (ESA) on Nov. 23 said its Schiaparelli lander's crash landing on Mars on Oct. 19 followed an unexplained saturation of its inertial measurement unit (IMU), which delivered bad data to the lander's computer and forced a premature release of its parachute. Polluted by the IMU data, the lander's computer apparently thought it had either already landed or was just about to land. The parachute system was released, the braking thrusters were fired only briefly and the on-ground systems were activated. Instead of being on the ground, Schiaparelli was still 2.3 miles (3.7 kilometers) above the Mars surface. It crashed, but not before delivering what ESA officials say is a wealth of data on entry into the Mars atmosphere, the functioning and release of the heat shield and the deployment of the parachute -- all of which went according to plan. In its Nov. 23 statement, ESA said the saturation reading from Schiaparelli's inertial measurement unit lasted only a second but was enough to play havoc with the navigation system. ESA said the sequence of events "has been clearly reproduced in computer simulations of the control system's response to the erroneous information." ESA's director of human spaceflight and robotic exploration, David Parker, said in a statement that ExoMars teams are still sifting through the voluminous data harvest from the Schiaparelli mission, and that an external, independent board of inquiry, now being created, would release a final report in early 2017.
https://en.wikipedia.org/wiki/...
How in hell did they test their Kalman filter to allow such bad data to reach the decision logic? (I assume they used one.)
Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
To be fair, few people did. Multiple cases of overflows and bad data problems have occurred and still continue to occur not just in space programs around the world but in other industries too.
even barometric altitude information
I'm interested to know how you calibrate your barometric altitude information, and even more so what vacuum followed by a sudden atmospheric entry will do to such a sensor.
If I'm going to take a guess I'd so no, an instrument capable in operating that range of pressures, temperatures, vibration, etc is not the size of a thumbnail weighing a gram.
He never said there was another person involved. He's just complaining about never managing to make it to the end of the pornhub clip.
Unicode killed the ASCII-art *
Dynamic range. Sensors which can measure from 0 - 100 g's are not as sensitive in the 0-1 g range you may be more concerned about. So you instead opt for accelerometers which max out at 10 g's and try to deal with the periods of max acceleration in software.
A more elegant solution is to use both the sensitive accelerometer and an accelerometer with a greater max threshold. That way you keep the higher max limit without giving up low-gain sensitivity. But spacecraft tend to be both weight- and budget-constrained...
More troubling to me was that there wasn't some basic sanity checking going on. Like a calculation that says "3 seconds ago I was at 4 km high. Now I think I'm on the ground. Does it make sense that I could've traveled that far in that little time? No? Then the instruments saying I'm on the ground are probably wonky, and I should give other instruments a higher priority in calculating my altitude for a bit." Same way I write my code (and spreadsheets) to calculate important numbers two, three, or sometimes even four different ways to make sure they all agree before proceeding to act on it.