Opportunity Mars Rover Still Working After Twelve Years

Mildly viral.

Really? That's nice!

Depends on the virus he's got, I suppose.

A pedantic engineer (like me) would contend that the Opportunity rover must have been grossly overdesigned for the job it was supposed to do. On the other hand, the non-pedantic engineer in me is thrilled with the achievement.

John@3: Speaking from experience, I can tell you that it is quite common for space missions to last significantly longer than the design lifetime. One of the big issues is exposure to energetic particles: MeV electrons can do nasty things to your electronics. So they take steps to mitigate against that, and as a result you get something that lasts for years. One project I was associated with was designed for a two year mission but was actually operated for 12 years.

Another issue is budgets: NASA doesn't want to commit to more than two or three years of full mission operations, because Congress might come along and cut their budget. I have seen operating missions in good working order that were terminated purely for budgetary reasons. So the instruments are officially designed for a prime mission phase plus a bit more for an extended mission, but are often operated for much longer.

Mars surface missions have other issues, such as dust, to deal with. But as with MeV electrons, the small steps that you take to mitigate against dust can greatly extend the lifetime of the rover.

Eric, I didn't know that you're in space tech! Is any of your hardware currently operating out there?

Eric,thanks.That's interesting and very understandable. I'm trying to think of what could qualify to give spectacularly over-length life for earth structures. Anything built by Roman engineers (2,000 year old roads and aqueducts still being used is pretty impressive), I guess, but they thought they were building for an empire that would last forever.

I always wanted to build a Roman aqueduct, but my time machine is malfunctioning.

@Martin: Yes, there is one instrument I worked on before launch that is still operating (15 years and counting). Another instrument has stopped working, but that was expected: it required a consumable (specifically, a supply of a certain gas) to operate, and the supply has long since been exhausted.

With terrestrial structures, you have enough examples to see long tails. Particularly in the days before they had a systematic approach, any structure that actually held up would hold up for a long time, barring war or natural disaster. The ones that didn't quite measure up are no longer standing. So it is with colonial area houses in the area where I live: the ones that are still around are quite solidly built, whereas the ones that weren't so solid have fallen apart. You can probably find medieval stone bridges here and there in Europe that are for pedestrian/bicycle use (of course they weren't designed for automobile traffic): the weight of the structure is much larger than the weight of the load, so if it held at all it could probably hold for centuries. Of course, terrestrial structures can be maintained, which is not the case with hardware in orbit.

That's amazing Eric! What mission / satellite is that? What instrument? Or is this military hardware that you can't talk about?

In the seventies, Britain launched a satellite that is still operating. Then they decided the government would support supersonic passenger air travel instead of this frivolous space thing...
Another sturdy device: "Rebooted Kepler spacecraft hauls in the planets" http://www.nature.com/news/rebooted-kepler-spacecraft-hauls-in-the-plan…

The Science Museum in London has a lot of interesting stuff from the sadly scrapped British space program. But I suppose they help fund ESA nowadays.

Yes, the UK still does space missions through ESA. There is at least one group that still builds instruments--they are affiliated with University College London, but the lab is actually in the Surrey Hills east of Guildford.

It makes sense to over-engineer anything you send out into space. I had a room mate back in the 70s who managed a small X ray observing satellite, possibly the first. He had to share the satellite with another group whom I would rather not name, and he was constantly fuming about what those guys at XXX would do to his satellite. They burned out a star camera (for orientation) by aiming it at the sun. They put it into a spin and somehow or another overwhelmed the nutation damper. As far as he was concerned his partner in the operating consortium was his dumb kid brother who always drove the car home on the fumes.

Luckily, there were two more star cameras. There were several other ways to damp the nutation though they did waste several orbits. Other stuff would burn out, but he'd just work around it. The satellite was apparently crammed with spare parts and launched with plans A through Z in mind.

They always used the toughest components they could get, usually MILSPEC, that is, meeting military specifications. He had a burned out MILSPEC transistor on his desk, and people would actually drop by to see it. MILSPEC transistors are over-built, tested and burned in. Most engineers had never seen a burned out one, though it looked like any other transistor to me.

NASA has taken some lumps over the years. Like the ESA, budgets vary with the winds and economic trends, but the engineers keep on plodding along.