Amount of fuel onboard, Potential life expectancy? Options

[briv1016]

Assuming that there are no MGS type anomalies and funding holds out (according to NASA's FY09 budget, the current extension ends in September); how much longer can Odyssey remain operational with the fuel onboard?

(I know you guys are strict about starting new threads, but I couldn't find any other thread related to this topic.)

[nprev]

...Don't think that anyone is strict about new threads per se, just relevant ones.

This one seems relevant indeed to me, anyhow, because I've been worrying over the loss of relay capability for surface missions. Relying solely on DTE links for future missions just doesn't seem like a good option, and there are no new Mars orbiters in the pipeline at present.

I sometimes fear that the embarassment of riches we currently have around Mars--three, count 'em, three!!!--orbiters doing hard science and providing relay service for three (count 'em!) active surface missions may lead to a sense of complacency. If nothing else, the comm infrastructure will have to be replenished to support future surface missions, and I find it worrisome that MRO looks right now like the long pole in the tent for MSL, ExoMars, and ASL.

[djellison]

http://mars.jpl.nasa.gov/odyssey/newsroom/.../20040825b.html
...The spacecraft has enough fuel onboard to keep operating through this decade and the next at current consumption rates.

A google search hints at far more details here - http://www.sciencedirect.com/science?_ob=A...78ab683f86ac8c3 - but it's clearly a pay-for paper.

"Odyssey was the first Mars relay satellite conforming to the CCSDS ... With 37 kg of fuel remaining and fuel use at a level of less than 1 kg/year, ..." Not sure if that's a contiguous citation from the ScienceDirect paper.


Doug

[TheChemist]

It probably is Doug. Citing from the above article :

Odyssey
"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."

MGS
"Current orbit operations have achieved very efficient fuel usage at the level of 1–2 kg/year; with over 8 kg of usable propellant available, operation through the time frame of the Phoenix 2007 mission is very likely; operations through the 2009 Mars Science Laboratory is possible but less certain."

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

*Edit*. Pardon the accidental necrology ....

[MahFL]

MGS died......

[nprev]

Yeah, and that's my point. Not getting a warm fuzzy for lander relay capability during the next decade at all, and I'd sure love to see a mission proposal for at least a gapfiller orbiter to cover the next three surface missions. When it comes to Mars, you need to wear a belt and suspenders, IMHO.

Long ago on another thread far, far away I proposed a transient event detection (TED) capability for a follow-on Mars orbiter. This would look for things like landslides, dust devils, CO2 geysers in the South Polar region, and maybe, just maybe, H2O hot spring detection. This seems like a viable science objective: understanding the nature and frequency of currently active surface processes is manifestly of interest across many disciplines, and certainly of great interest to long term manned mission planning. And, of course, any orbiter would have a relay capability for surface missions.

To me, this looks like a desirable convergence. Hell, I'll even admit that I invented TED to sex up the idea of a new orbiter...because the bottom line is that sooner or later we're gonna need one quite badly.

[djellison]

Not getting a warm fuzzy for lander relay capability during the next decade at all,

Well - I'm not getting a warm fuzzy feeling for a requirement for lander relay capability during the next decade either.

Seriously - MSL is the only landed asset firmly scheduled. That's it. The next up to the pad is, currently, the last.

We do have the next scout, which will be an orbiter with at least Odyssey like relay ability - which will (if you presume a decade lifespan) relay capacity out to at least 2020+. There's no reason to expect MRO, MEX and MODY to all die especially soon either. MRO, imho, will last a LONG time.

Doug

[nprev]

Hope so...but as an old crusty avionics maintenance guy, I'll naturally advocate redundancy, redundancy, redundancy!

I see your point, Doug. One thing I didn't mention though is what might be planned for MSR, if anything. By the time it flies (2020+) under the current schedule it becomes increasingly less likely that any present orbital assets will still be operational. Hate to rebuild infrastructure from scratch all the time, every time. We've GOT one now, and that certainly provides a supporting argument to maintain the mission pace.

[elakdawalla]

Thanks guys, this'll be this week or next week's Q and A

--Emily

[briv1016]

Thanks guys.

[andrea]

One thing to consider is that not all relay capabilities in the existing orbiters are equal.

MRO relay capabilities (higher data rates and the capability of changing data rates during a pass) will allow MSL a 4x,5x times the data volume is possible with ODY (MEX has even lower data rate 128 kbps and an eliptical orbit that do not make the tactical planning easy). Phoenix and the MERs have the same UHF radio as ODY and cannot really take advantage of the MRO capabilities. So while I am extremely proud on how Odyssey relay worked all this year, the functional redundancy does not offer the same capabilities. If MSL lasts many many years this could be indeed a problem.

For EDL communications also more the better. The overall MSL launch/arrival strategy is terrible complicated amongst the other things so that at least one orbiter will cover.

This is an area where Europe should definitely step in and help fill in some gap.

Well - I'm not getting a warm fuzzy feeling for a requirement for lander relay capability during the next decade either.

Seriously - MSL is the only landed asset firmly scheduled. That's it. The next up to the pad is, currently, the last.

We do have the next scout, which will be an orbiter with at least Odyssey like relay ability - which will (if you presume a decade lifespan) relay capacity out to at least 2020+. There's no reason to expect MRO, MEX and MODY to all die especially soon either. MRO, imho, will last a LONG time.

Doug

[Mariner9]

I rather doubt having 3 operational orbiters and 3 landers is something that is likely to be the norm for the next decade.

Aside from the fact that Mars Express was a one-shot mission, I think the main culprit is cost.

Looking at the ballpark cost figures for the Mars missions,

MGS - 250 million
Mars Odyssey - 300 million
MER - 800 million
MRO - 700 million
Mars Phoenix (scout) - 400 million (really closer to 500 when you consider they got the base spacecraft for free).

Then looking at the future (that is far from set in stone, and is shifting as we speak)

MSL - 1.9 billion
Mars Scout 2011 (now 2013) - 425 million
MSO 2013 (now 2016 +) - 700 million
Mars Exobiology Rover - 1.5 billion
Mars Networking mission - 1 billion plus



Roughly speaking, we seem to have left an era where the mission costs were 300-700 million, and went into one where they are 450 - 1.5 billion.

In other words, we got our current infrastructure at mission costs roughly half what the upcoming missions look likely to cost.

So, while on the surface of things it makes sense to argue to "keep the mission rate up", the problem is that the upcoming missions are much more expensive. If we were talking Mars Surveyor and Mars Scout missions, it might be possible under the NASA budgets. But I just don't see how they can keep launching a mission every 26 months if they keep increasing the cost per mission.

[Guest_PhilCo126_*]

Mars Odyssey performed well (Launched April 2001, Mars orbit since 24th October 2001) but its second extended mission was due to end in October 2008. Will NASA keep it alive after Phoenix Lander gave its last breezy breath ?

[nprev]

I don't see why not. An operational mission is worth an infinite number of mere mission proposals. Don't think we've ever just shut one down, we just run 'em till they break.

[MahFL]

It's good till at least September 2010.

"NASA's Mars Odyssey is altering its orbit to gain even better sensitivity for its infrared mapping of Martian minerals. During the mission extension through September 2010, it will also point its camera with more flexibility than it has ever used before. Odyssey reached Mars in 2001"

http://www.jpl.nasa.gov/news/news.cfm?release=2008-191

[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