NASA Mars Rover Spirit May Move Forward By Spinning Its Wheels 175
coondoggie writes "As NASA celebrates its Mars rover Spirit's sixth anniversary exploring the red planet, it is hunting for a way to keep the machine, which is mired in a sand trap, alive to see a seventh year. On its Web site, the space agency this week noted there may indeed be such an option. That option would be spinning the wheels on the north side of Spirit, letting it dig in deeper in the Martian sand but at the same time improving the tilt of the rover's solar panels toward the Sun."
maybe next time they can put a little backhoe... (Score:0, Interesting)
Heh (Score:4, Interesting)
You know what the solution to this problem is? Send more rovers. Lots more. If we had a spare rover near Spirit, we could probably have it roll over and give Spirit a tow...
Re:Heh (Score:3, Interesting)
You know what? I'm not a NASA planetary exploration scientist, but that sounds like an interesting idea.
Send rovers in pairs, each with half the instrumentation load, but tethered together by a cable. One gets stuck, the other pulls it out. Give the cable a release so if one rover dies, the other can continue with the remaining instruments.
Re:Heh (Score:5, Interesting)
One of the key issues is having power enough to heat them in the winter.
If the supposedly 'enlightened' greenies wouldn't raise a huge ruckus, the answer is to either alloy Gadolinium 148 into the frame or just have a block of it hanging around. It gives off a huge amount of heat, and essentially no radiation that would harm the rover (it's one of the few strong pure alpha-emitting isotopes).
A fascinating paper [nanomedicine.com] on powering medical implants with radionuclides states:
A ~0.2 kg block of pure Gd148 (~1 in^3) initially yields ~120 watts, sufficient in theory to meet the complete basal power needs of an entire human body for ~1 century (given suitable nucleochemical energy conversion and load buffering mechanisms, and a sufficiently well-divided structure).
Also from that paper, an amazingly small sphere of Gd 148 can power small implants:
Among all gamma-free alpha-only emitters with t1/2 > 10^6 sec, the highest volumetric power density is available using Gd148 (gadolinium) which a-decays directly to Sm144 (samarium), a stable rare-earth isotope. A solid sphere of pure Gd148 (~7900 kg/m3) of radius r = 95 microns surrounded by a 5-micron thick platinum shield (total device radius R = 100 microns) and a thin polished silver coating of emissivity er = 0.02 suspended in vacuo would initially maintain a constant temperature T2 (far from a surface held at T1 = 310 K) of [ 600 K ] with a 75-year half-life, initially generating 17 microwatts of thermal power which can be converted to 8 microwatts of mechanical power by a Stirling engine operating at ~50% efficiency.
Re:And one should add (Score:5, Interesting)
Was it really designed for 90 days? It could be that the only way they could sell it to Congress was if they told them that they only had to pay for technicians for 3 months.
Well, yes and no. The models suggested that the solar panels would be clogged up with dust so it'd be like a car with an empty gas tank, after 90 sols it'd be still in great condition but out of juice so that was the mission. In practice dust devils clear most of the dust, but noone knew that before they arrived. Perhaps some speculated and hoped, but certainly not knew or assumed. Nothing about the rover was intentionally limited to three months, though if they knew they'd be out there for many years I'm sure some design choices would have been different. But that's why we can send a second generation if and when these rovers finally kick the bucket.
Re:Heh (Score:3, Interesting)