Amount of fuel onboard, Potential life expectancy? Options

[Guest_PhilCo126_*]

Great that made my sol

Remember Mars Global Surveyor worked for 10 years ( 7th Nov 1996 - 2nd Nov 2006 ) so fingers crossed that Mars Odyssey will go to 2010

[tedstryk]

Great that made my sol

Remember Mars Global Surveyor worked for 10 years ( 7th Nov 1996 - 2nd Nov 2006 ) so fingers crossed that Mars Odyssey will go to 2010

Not to mention that MGS was killed by a software error - it could still be chugging along.

[nprev]

Yeah...but then again, similar sorts of things could happen to any spacecraft, anytime. Gonna repeat the mantra again: 'redundancy, redundancy, redundancy...'

[tedstryk]

My point is that it didn't have anything to do with age.

[rlorenz]

My point is that it didn't have anything to do with age.

Of the hardware, no. But a project is more than that. There is continuing pressure
to cut costs of an ongoing mission to open up a funding wedge to buy the next big
mission. So you pay for fewer man-hours, have fewer pairs of eyes double-checking things,
maybe hire cheaper/less experienced people (indeed, even if you can pay for old hands
to stay on, some talented/ambitious engineers may see starting on a new project as better
for their careers than staying on an 8-year old project that could croak at any time.) So I'd
venture there is a 'project aging' effect independent of the space hardware segment.

It would be interesting to see statistics on commanding errors as a function of mission age.
I am sure the absolute rate may fall, since things become routine, but I wonder what the
errors-per-new-thing-tried is...

[djellison]

So I'd
venture there is a 'project aging' effect independent of the space hardware segment.

MGS was a particularly bad case of this, iirc. VERY old avionics compared to Mars Odyssey - (the very very inaccurate and brief version is....) and the guy who'd happily uplinked to MGS for years, retired, and his replacement didn't know the avionics inside out - hence the wrongly uplinked parameter that only got picked up during the solar array motor induced safing event.

[nprev]

Hmm. There are a lot of ways to think about this. Systems engineering models can't catch every critical dependency, of course, but it sure seems like you could define a point in a system's life-cycle where the total entropy (using the term very loosely) makes a fatal event almost inevitable. Heck, if you plotted entropy vs. time I bet it's some sort of exponential function that takes off right near the end of the curve.

[tty]

In my experience the critical resource in keeping old systems running is almost always people. It takes a long time to understand a complex system really well. You just try to go in to your boss and say "I'm retiring in 5 years, it's time to hire someone to take over after me". This is especially true if the system you're running is scheduled to be phased out in, say, 4 years. I know a system that has been a year or two away from phase-out for 15 years now, while the planned replacements have repeatedly failed spectacularily and expensively.

[brellis]

"The Odyssey mission is in excellent health, with none of its avionics redundancy yet exercised. With 37 kg of fuel remaining and fuel use at a level of less than 1 kg/year, it is possible that Odyssey could continue to provide relay services well into the next decade."

Since the article was published in 2006, two years of fuel should be substracted for current estimations.

Looking forward to many more years of Odyssey!

[kenny]

Hard to know quite where to put this post, but "fuel" seems appropriate somehow.

The Houston Brewing Company in Houston, Renfrewshire, Scotland (the original place of that name), is producing monthly space-themed beers, and the September one is a reddish ale called Mars Odyssey. I had some last night - rather pleasant.

Mars Odyssey beer