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Bad Code May Have Crashed Schiaparelli Mars Lander (nature.com)
cadogan west writes "In the accordance with the longstanding tradition of bad software wrecking space probes (See Mariner 1), it appears a coding bug crashed the ESA's latest attempt to land on Mars." Nature reports:
Thrusters, designed to decelerate the craft for 30 seconds until it was metres off the ground, engaged for only around 3 seconds before they were commanded to switch off, because the lander's computer thought it was on the ground. The lander even switched on its suite of instruments, ready to record Mars's weather and electrical field, although they did not collect data...
The most likely culprit is a flaw in the craft's software or a problem in merging the data coming from different sensors, which may have led the craft to believe it was lower in altitude than it really was, says Andrea Accomazzo, ESA's head of solar and planetary missions. Accomazzo says that this is a hunch; he is reluctant to diagnose the fault before a full post-mortem has been carried out... But software glitches should be easier to fix than a fundamental problem with the landing hardware, which ESA scientists say seems to have passed its test with flying colours.
The most likely culprit is a flaw in the craft's software or a problem in merging the data coming from different sensors, which may have led the craft to believe it was lower in altitude than it really was, says Andrea Accomazzo, ESA's head of solar and planetary missions. Accomazzo says that this is a hunch; he is reluctant to diagnose the fault before a full post-mortem has been carried out... But software glitches should be easier to fix than a fundamental problem with the landing hardware, which ESA scientists say seems to have passed its test with flying colours.
This wouldn't have happened if they'd used imperial not metric!
New age hippie liberal airheads. If it's not a hogshead, it's not fresh!
"First they came for the slanderers and i said nothing."
They're still unwilling to concede that their defenses against the Martian's OBDS (Orbital Bombardment Defense System) is inadequate.
Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
How are you going to issue a software patch to the pile of rubble on another planet? This is not a situation where you can ship the product without testing and fix it in firmware later!.
It's Agile. The product owner will raise this issue as a priority in the backlog, they'll fix it in this sprint, and it will ship in the next release.
John
I know people that work in companies that design chips. Those manufacturing cycles are MUCH longer and expensive - you can't just recompile when you test and find a bug. This, their QA is probably more like 10 people doing simulation (behvioral, thermal, timing, power, emissions, RF susspetabiliy, etc) before a design is even fabricated.
I would imagine that in Space Exploration - this would go even higher - given the time and expense of these missions. The point is - saying "it's just software" doesn't help you here. Software is *very* complex and the intricacies of advanced logic, variability of factors - trying to do this stuff probably dwarfs that of the hardware components in this day and age.
Testing on another planet is not that easy, though.
Yes, test it all in production.
Since testing is sooooooooo hard.
Landing is the most complicated part and Beagle and others have failed exactly here. There should be x100 or even more code for unit and integration testing than the actual code itself for the landing code. And, those tests should run through every permutation possible of every possible failure point or bad sensor readings.
There is no way it thinks it has landed with that many sensor inputs. It is simply code that is not put through a good enough testing system.
Usually when that sort of thing happens, it's not because the programmer did something obviously wrong. It's usually because the programmer had two (or more) competing scenarios to design for. He tried to design something which would split the difference, and ended up erring too much to one side.
Lufthansa flight 2904 is a good example. The plane had to land in an expected crosswind on a wet runway. A crosswind landing requires landing with the plane's orientation misaligned from the runway. The plane is pointed into the crosswind, so is actually landing diagonally, then when it hits the ground it has to quickly yaw so it's aligned with the runway (so the wheels are pointed in the right direction). The way this is done is it lands on one gear first, pivots around on that gear to point the nose at the end of the runway, then drops down the second gear, then the nose gear.
The A320's flight computer was programmed to avoid the disastrous scenario of a thrust reverser deploying in mid-air. It prohibited deployment of the thrust reversers unless both rear landing gear had 6.3 tons of force each on them. Full deployment of the spoilers (disrupts lift to plant the plane firmly on the ground) was prohibited unless the 6.3 tons criteria was met or the wheels were spinning faster than 72 knots.
Unfortunately, in flight 2904's case, the crosswing landing maneuver placed most of the initial the force on a single landing gear, so the thrust reversers didn't deploy. The wet runway caused hydroplaning so the spoilers failed to deploy, hindering the pilots from getting the second landing gear down. By the time the above criteria were met and the plane began slowing down, it was well past the halfway point of the runway, and ended up going off the end. Design criteria selected to prevent one type of accident inadvertently caused another.
everything is going to hell.
No, everything is calling hell() as a function.
systemd is Roko's Basilisk.