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What really happened to the software on the Mars Pathfinder spacecraft?

rapitasystems.com

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Re: What really happened to the software on the Mars Pathfinder spacecraft?

#4

Post by ams6110 »

Engineers later confessed that system resets had occurred during pre-flight tests. They put these down to a hardware glitch

This doesn't really ring true to me. Sounds like the sort of programmers who are inclined to blame "cosmic rays" for odd behavior that they don't understand.

I would think on a mission as expensive as the pathfinder, and knowing that once the hardware is launched you will never have physical access to it again, ANY anomalous behavior would have been tracked down to root causes during testing.

Re: What really happened to the software on the Mars Pathfinder spacecraft?

#6

Post by gizmo686 »

ams6110 wrote: post #4

Engineers later confessed that system resets had occurred during pre-flight tests. They put these down to a hardware glitch This doesn't really ring true to me. Sounds like the sort of programmers who are inclined to blame "cosmic rays" for odd behavior that they don't understand. I would think on a mission as expensive as the pathfinder, and knowing that once the hardware is launched you will never have physical acc…

>\Sounds like the sort of programmers who are inclined to blame "cosmic rays" for odd behavior that they don't understand.

In fairness, they go out of their way to harden they computers against cosmic rays. I am sure that they make a decision about what an acceptable amount of cosmic ray induced error is, and design the system knowing that it will happen. Having said that, I agree that having unexplained problems on the ground should get an explanation before being launched. Even if it was a hardware glitch, they should either have told the hardware people that there was a glitch, or the level of error was within the designed for range and they should not have been suprised when it happened in space.

Re: What really happened to the software on the Mars Pathfinder spacecraft?

#7

Post by joezydeco »

comatose_kid wrote: post #5

I did some embedded sw on vx works based systems back in the day. Any embedded engineer we interviewed had to know what priority inversion was.

Yeah, this has been a common topic in any embedded job interview I've had since the 90s, and not just on VxWorks jobs. The Pathfinder case study is pretty well known.

Re: What really happened to the software on the Mars Pathfinder spacecraft?

#8

Post by nknighthb »

gizmo686 wrote: post #6
ams6110 wrote: post #4

Engineers later confessed that system resets had occurred during pre-flight tests. They put these down to a hardware glitch This doesn't really ring true to me. Sounds like the sort of programmers who are inclined to blame "cosmic rays" for odd behavior that they don't understand. I would think on a mission as expensive as the pathfinder, and knowing that once the hardware is launched you will never have physical acc…

>\Sounds like the sort of programmers who are inclined to blame "cosmic rays" for odd behavior that they don't understand. In fairness, they go out of their way to harden they computers against cosmic rays. I am sure that they make a decision about what an acceptable amount of cosmic ray induced error is, and design the system knowing that it will happen. Having said that, I agree that having unexplained problems on…

In further fairness, Pathfinder's name was also its job description. It was built on a relative shoestring and in a way, fulfilled its most important function the moment Sojourner rolled onto Martian soil. It was basically a combination prototype/advance scout.
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