Mars Rovers' Mission Extended Another Six Months

what_the_frell writes "Looks like the Mars rovers, Spirit and Opportunity, will be online and in use for at least another six months, after surviving the lowest point of the Martian year, in terms of sunlight. New Scientist has a fascinating article on this and some of the other hurdles the rovers have tackled. It's pretty cool how the rovers have far exceeded their initial 30-day mission (today is Day 263), and that their new projected mission is now well over 365 days."

Comments

What was behind the initial 30 days?

[Marxist Hacker 42]

Ok, so what part only had a 30 day warrenty, and who built it to exceed tolerances by a factor of 10?

Re:What was behind the initial 30 days?

[I_Love_Pocky!]

NASA's high failure rate makes modest goals a reasonable expectation. Any number of things could have gone wrong, but luckily they didn't.

Re:What was behind the initial 30 days?

[noselasd]

Solar panels, which they assumed would be covered with dust after a while, and not provide enough power.

Re:What was behind the initial 30 days?

[Anonymous Coward]

NASA's high failure rate makes modest goals a reasonable expectation. Any number of things could have gone wrong, but luckily they didn't.

I think you mean the high failure rate of robotic probe missions to Mars in general. Look it up yourself if you don't believe me, but the failure rate of the total missions to Mars, from four different space agencies, is about 33%. NASA, by the way was reponsible for a significant proportion of the total successes.

Re:What was behind the initial 30 days?

[Anonymous Coward]

Even if everything went right they still only expected the rovers to last maybe a hundred days.

The solar panels undergo a chemical reaction with the dust in the air which causes them to become less and less productive over time. (no, they can't be cleaned, the dust actually chemically bonds to the panels). They apparently overestimated the rate of this decay.

It is quite surprising they have lasted this long. Now that they have good data on how fast the solar panels actually are decaying, their current estimate should be right on the money, however a mechanical failure becomes a more likely failure mode as the parts overextend their expected lifetime by so much and this can't as easily be predicted.

Re:What was behind the initial 30 days?

[eingram]

Couldn't they just attach some kind of minor vent system that would blow off at least some of the dust that collects on the panels?

Re:What was behind the initial 30 days?

[Mark of THE CITY]

Mars has a thin atmosphere.

On Earth, standard atmospheric pressure is 101.325 kPa.

On Mars, it is 0.7-0.9 kPa.

Re:What was behind the initial 30 days?

[eingram]

Still seems enough to blow dust around the entire planet, surely it could blow a little off some solar panels? Especially if it took in air and compressed it then let it go.

Or even bring our own "canned air" and use it when the solar panels are working x% of normal.

You can't tell me there isn't some sort of solution to combat this problem for future missions (well, unless of course problem was money/budget related, then I understand).

Re:Oh really?

[Anonymous Coward]

Read the article? You're new here aren't you?

Fascinating?

[traveyes]

That was a fascinating article???

Whoah... you'd better stay away from here.

You just might have a coronary thrombosis.

.

Sorry

[bobdotorg]

Heard on a local Martian newscast,

"I for one welcome our new roving overlords."

Re:Sorry

[Tablizer]

...welcome our new roving overlords."

Shortened to "Roverlords"

Time for something exciting...

[Lindril]

Enough moving 0.27 meters at a time and staring at rocks. There's nothing left to do that hasn't been done in that department. It's time for something new.

Let's have the rovers meet up and let the operators play a game of Martian chicken.

Re:Time for something exciting...

[Anonymous Coward]

Enough moving 0.27 meters at a time and staring at rocks. There's nothing left to do that hasn't been done in that department. It's time for something new. Let's have the rovers meet up and let the operators play a game of Martian chicken.

And glue the most annoying slashdotters on the bumpers, giving them really thin suits.

Expectation managment

[HaiLHaiL]

Is this really just a case of expectation management? NASA says "the rovers will last 30 days," to cover their asses if some unknown factor takes them down far sooner than the hardware could manage? Then when they last longer, NASA can do some gloating? Not that it's malevolent, but did the rover engineers really expect them to only last 30 days?

Re:Expectation managment

[Anonymous Coward]

Is this really just a case of expectation management? NASA says "the rovers will last 30 days," to cover their asses if some unknown factor takes them down far sooner than the hardware could manage? Then when they last longer, NASA can do some gloating? Not that it's malevolent, but did the rover engineers really expect them to only last 30 days?

No, because they were initially advertised as 90 days. The summary has it wrong, but the article has it right.

Re:Expectation managment

[Tablizer]

IIRC, some of the contractors who built them are not fully paid unless related subsystems last at least until the "warrantee period" is up. Thus, the warrantee periods are not (just) political boundaries.

Re:Expectation managment

[snake_dad]

No. Several components (4 or 5, at least that order of magnitude) have already failed or degraded. Luckily all those failures could either be repaired (the onboard computer failure on Spirit, early in the mission), or worked around (a sensor on the arm of Opportunity IIRC, degraded wheel on Spirit), or has not caused significant damage (stuck heater on Opportunity,switched off now with risk of damaging the Miniature Thermal Emission Spectrometer). On the other hand, the solar panels power did not degrade as much as feared. (And, as other said, original mission was 90 days, not 30).

Mars is tough on probes

[Tablizer]

Ok, so what part only had a 30 day warrenty, and who built it to exceed tolerances by a factor of 10?

Mars is a tough environment. The biggest problem is the wide tempurature range between day and night. On earth, thermal cycling is part of what cracks rocks into sand.

Such cycling can crack or damage electronics without warning.

Related is lubricant problems. The lubribant has to work in a wide range of tempuratures, and survive the "cooking" phase when the rovers are dissinfected on earth. One of the rover wheels seems to have lubricant problems, limiting the rover's range.

Then there is the dust that is everwhere on Mars which coats everything, including solar panels.

30 days?

[Omeganon]

That's inaccurate. The original mission was slated to last 90 days, not 30.

Re:30 days?

[stevesliva]

And the unit of measure is underspecified. It's 90 Martian days, or Sols.

Obligatory rover home page link

Not just the dust...

[Chmcginn]

It wasn't just dust accumulating on the panels that was supposed to degrade their performance... the change in season, and the eventual loss in maximum battery charge after cycling them so many times... This page sums it up.

From what I understand, it wasn't directly a money related problem, it was a weight related problem. As in, they had a set size limit for the rover itself, which was set by the size of the transport, which was set by the size of the rocket used to get it from Earth to Mars. Since it was assumed the lower inclination of the Sun after about 90 days would make the rover unable to hold a charge, they didn't figure it was worth the effort to include a broom. Of course, then, after they got it there, somebody had the idea to park it with the southern side uphill, so the panels would be more directly hit by the sun. Of course, now other stuff is starting to fail...