Mars Rover Spirit Down a Wheel

riflemann writes "NASA is reporting that two years into its 90-day mission, Spirit has lost one wheel and is now running on five wheels, dragging the broken wheel. With this reduced mobiity, the rover still needs to make its way to a slope where it can catch enough sun over the Martian winter to keep it operating. 'Even though the rovers are well past their original design life, they still have plenty of capability to conduct outstanding science on Mars.', says project leader Dr. John Callas."

Comments

At first read, I get dissapointed

[R2.0]

Then I remember a story Spider Robinson told about a cheap digital watch that died on him. He was pretty pissed off, but then he remembered that:

a) it was originall a Crackerjack prize or some other freebie.

b) it was 5 years into it's projected one year battery life.

At this point he gave it a solemn memorial service and kept it in a revered place (I think he may have buried it).

Whenever they finally die, I hope that they find an honored place in whatever museum the future Mars colonists decide to set up.

R2.0

Re:At first read, I get dissapointed

[HoneyBunchesOfGoats]

Or, car manufacturers could decide that you'll assume "longer warranty == longer-lasting car," raise their warranty to 80,000 miles regardless of the fact that the car is crap, and bank on the fact that you'll want a new car within a couple years anyway.

exploration will continue

[MoFoYa]

I think its great that the mars rovers lasted as long as they have. when you consider the failed mars mission attempts, spirit and opportunity are huge successes that have long outlasted their expected lifespan. The new mars orbiter "MRO" is sure to provide more information about the surface of mars, and possible landing sites for even more capable landers in the future. my question to /.ers is this: should we be focusing so much on mars or should we be looking toward other possible outposts/life harboring worlds like europa. and the new horizons mission to pluto - a waste of time, or an exciting new learning opportunity? personally, i doubt life will be found on mars. and i'm doubtfull any significant life will be found anywhere in our solar system. but, we are natural explorers who will continue to explore, even with a bum wheel.

Re:Not so surprising

[slightlyspacey]

What do you expect? The rover has lasted *8* times longer than design. That's the equivalent of driving 400,00 miles on tires rated for 50,000 miles. It's a heck of an accomplishment and I can only applaud the terrific job the design engineers and builders did.

I'm still amazed....

[zappepcs]

This robot was supposed to last about 9 months... I think it has gone waaayyyy past the rated mileage for that wheel. The fact that it is free-wheeling and not a major hinderance is just a testament to how well it was actually designed. This 3x life-span thing is incredible if you take into account all of the challenges that the designers faced. I dabble in hobby robotics, and I can attest to the fact that designing a robot that does as well as it has done for as long as it has done, is a major accomplishment. Think about the warranty that you get on a new automobile... if it performed past its expected lifetime of usefulness to the tune of 300 percent, people would be driving vintage cars all over the place.... it is an amazing robot and planetary exploration vehicle!

Re:I'm still amazed....

[zappepcs]

Those are very good points, but I think that most of the reason for the unexpected longevity of the mars rovers is that they expected dust from dust storms to critically hamper the solar panel operation. What was a surprise is that the wind quite effectively kept the solar panels clear of dust, giving a much longer lifetime. I don't think that the engineers expected to have to worry about the motors lasting 36 months or more since it was not expected. Mars has quite extreme temperature swings, so the engineering is probably worth what it cost to build the rovers. Mother nature is something that just can't always be anticipated, unless, of course, you anticipate problems due to mother nature. In that case, any positive turn of fate leaves you in the position of underestimating vehicle longevity.

The temperatures, radiation, dust, vibration... these are very harsh environmental variables. It is just amazing that they are still running. I'm sure that NASA is still as amazed as we are, and pleased to be continuing the scientific research at what amounts to a budget bonanza.

You are most probably right in thinking that what was learned this time around will be incorporated in the next planetary exploration vehicles, and a longer lifetime expectation will be part of that. In line with that, recent NASA un-manned missions have been incredibly successful. I look forward to more solar system exploration, and also to commercial exploration based on NASA work.

Now that we know how to build robots to explore Mars, we can build them to explore other planets, and that ion engine thing is a Trekie's dream. The expectation bar is rising, and that is a good thing. The X-prize and similar efforts are creating huge scientific 'wealth' for all to use. Its all very cool.

Re:Failed brushes?

[HoneyBunchesOfGoats]

I have a hunch that the brushed motors NASA used in the rovers are probably a little bit more expensive and higher-quality than what you're used to dealing with on miniature airplanes. There are most likely some design issues we don't know about that made them use a brushed motor.

Tire tracks, not water

[tilde_e]

It is so interesting that we leave tire tracks on other planets. They may be that the first signs of life we find, or that other beings find.

Imagine the tension if we found ourselves face-to-face with a foreign martian rover!

Re:Failed brushes?

[Tablizer]

While NASA is very proud to have exceeded expectations with the Rovers, I think this is mostly because their expectations of solar powered vehicles were so abominably low. Perhaps they will take things more seriously from now on.

Their budget was for 90 working days. That is how the contracts stipulated payment. Further, the solar panels have been cleaned repeatedly by dust devils. Experience with the 2 Viking landers showed that dust builds up pretty quickly on probes and they understandably factored this into the design. The dust devil cleansing was a lucky accident. They had no certain landing areas picked out when the rovers were being designed, so they could not expect to rely on landing in whirl-windy areas, even if such could be identified from orbit. (It appears there are more dust devils near the equator than where the Vikings landed. However, there are probably also regional variations, based on the "criss-cross" patterns seen from orbit and created by dust devils.)

In fact, it has been a while since Spirit has been cleaned by one, and that is one reason they have to rush to sun-facing slope. Future crafts that land in non-whirl-wind areas of Mars may face an early demise if they rely on solar (unless they bring their own cleaning systems).

I believe Spirit had about 2 whirl-wind "cleaning sessions". Next year when the winds pick up it may have 4 or zero. It is the luck of the cards that determine it, and so far only during the summer. Thus, Spirit may have a sluggish spring.

In short, I see no reason to bash Nasa's general approach. Sure, it would be nice to have a fat budget to include bells and whistles for extended missions, but the budget is the budget. Plus, they had a fairly short ramp-up time between approval and build. They had to use a lot of existing Sojourner technology almost as-is to reach the deadline.