4 ms·
The simpler statement would be: the lander started to spin after the parachute opened, and the sensor properly detected that it rotated a lot, giving the maximu
by acqq 10y ago
The simpler statement would be: the lander started to spin after the parachute opened, and the sensor properly detected that it rotated a lot, giving the maximum value as an output, but the rotation lasted for at least one second and we made the rest of software without having any idea that this could happen, so this one sensor output confused the whole lander. Or even shorter "nobody here expected it could spin the whole second."
Once the model is so simple, there are many ways to program it wrongly.
To compare, NASA's Mars Climate Orbiter
https://en.wikipedia.org/wiki/Mars_Climate_Orbiter https://en.wikipedia.org/wiki/Mars_Climate_Orbiter
burned close to Mars in 1998 because the "ground based computer" programmed per contract by Lockheed used lbf·s values instead of agreed N·s values.
https://en.wikipedia.org/wiki/Pound_(force) https://en.wikipedia.org/wiki/Pound_(force)
The values generated on the ground were 4.45 times bigger.
Space missions are risky.
- fest 10y agoIMO it's more likely that accelerometer instead of gyroscope would saturate, and the sentence that explains IMU is shortened too much.
- acqq 10y agoMaybe. The only thing I can conclude from the description is just that the lander was simply spinning too long (too long as in "the whole second") for their software to handle the correct information from the sensors. Now it sounds too simple. But it's good that they made such an experiment before sending the whole rover, planned for 2020. https://en.wikipedia.org/wiki/ExoMars_(rover) https://en.wikipedia.org/wiki/ExoMars_(rover)