Mars Rovers Have Incorrect Instruments Installed

Christopher Reimer writes "The New Scientist is reporting that the twin Mars rovers, Opportunity and Spirit, has instruments installed in the wrong rovers. From the article: 'While the bungle does not undermine the main scientific conclusions drawn from the data collected by the rovers, it is an embarrassing slip-up for a space agency that once lost a Mars spacecraft because engineers mixed up metric and imperial units.'"

Comments

Confusion...Why differing configurations?

[Alpha_Traveller]

Creeping errors
Although their designs are identical, each instrument is unique because of quirks in the materials they are made from. So before the rovers were launched, each instrument was calibrated using known rock samples. The measurements from each rover are then processed using the calibration files, but because of the mix-up, researchers were using the wrong ones. As a result, small errors have crept into the APXS results, affecting measurements of sodium, magnesium and aluminium abundance.

Perhaps someone can clarify this statement? (Since I am not an engineer, eh?)... I'm wondering why it's so important to have differing configurations for the sensors in the first place. Wouldn't it be wise to collect exactly the same kind of information regardless of how complex if it's all being sent via transmission back to us anyway? Wouldn't it be extremely important to have the exact same configuration on BOTH sensors? I would think the end result would be useful when comparing the chemical composition of any particular area. It would be like hacking off a sensor "at the knees" when you had no significant reason to do so wouldn't it?

Re:Confusion...Why differing configurations?

[Anonymous Coward]

In the old days, if you bought a carbon +/-10% resistor, you could be assured that it was either -10% to -5% or +5% to +10%, and almost never in-between. The reason? They'd mark the ones that fell between as +/-5% and sell them for more moeny.

This doesn't work for +/-5% and the next grade (+/-1%) because the parts are built differently.

Cat calls from the cheap seats

[amightywind]

Let the New Scientist criticize from the cheap seats. It is hard to argue that the rovers have been anything other than a resounding success for over 400 days. I would have hoped /. would instead print the recent story of the Spirit Rover discovering salty soil.

Re:No big deal...

[Aglassis]

"Compared to the fact that the rovers are still running long after they were expected to die, this is a tiny, tiny thing."

Except for the fact that the same organization that made this error is designing other spacecraft. If they don't get to the root causes of the problem, like the failure of the technicians to properly follow the correct procedure to install the instrument and the failure of any other engineer or management to catch their failure to follow procedure, much larger problems could occur. Lets examine a couple of JPL's problem's in the last couple of years:

Galileo: High power antenna failed to deploy resulting in a much lower data transfer rate. This was due to technical specifications in the lubrication of the antenna not being reviewed when the project was delayed.
Mars Climate Orbiter: Burned up because the technical requirements were not met (converting from BES to metric).
Mars Polar Lander: Lost on landing. Cause is not known. Project team was rushed in accordance with faster, better, cheaper plan.
Genesis: Failed to deploy parachute and crashed on landing due to technical requirements not being met (backwards specification for G-force meters).
Mars Exploration Rovers: Software glitch early in mission due to failure to test software for its entire expected lifespan. Instruments swapped due to failure to follow procedure.

Some things we can get out of this analysis are that the QA was unsatisfactory. Procedures were not followed. Technical specifications were not verified. The culture was rushed (go-fever or product push environment). None of these are small problems, but they also point to much bigger problems: failure of the leadership to properly plan the project so that rushed timelines would not occur. This same culture is building new spacecraft. While JPL is a great agency and they do tremendous and incredible feats, they are not perfect and have lost several spacecraft and have had severe faults in others. These problems did not have to occur and more importantly these problems do not have to occur again in the future.