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?

[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?

[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.

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"

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

[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.

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...