NASA Extends Rover Occupation of Mars

iocat writes "Reuters reporting that NASA is extending the Rover missions on Mars by another five months. However, they point out that while the rovers look poised to greatly exceed their planned life cycle, they could basically die at any time. Still, it will be cool to see a little more exploration."

Almost first post

[Pi_0's don't shower]

I wonder how much terrain these rovers can explore in 5 months, or if they're basically useless because of range limitations?

Excellent!

[qualico]

Its always good for future missions if the current ones exceed expectations.

Looking at Mars, now a distant orange glow in the sky, it amazes me that we have intelligence there.

Good job NASA.

Let's hear it again for JPL

[Steve the Rocket Sci]

Pasadena's Jet Propulsion Laboratory (JPL) has done it again, it would seem. When the Voyager 1 and 2 missions were launched in 1977, they estimated that they would only last until the encounter with Saturn roughly four years later. Now, in 2004, they are still returning useful data, at a distance of over 90 AU from the Sun (in comparison, Pluto is only 40 AU from it). Sure, they had their problems during the mission, but it looks like Spirit and Opportunity may share a similar quality construction. It's definite that they won't last 27 years, but with how well they are functioning, I think the only limit will be the Martian dust collecting on their solar panels. When they Next Generation Rover lands on Mars in the latter part of this decade, it will hopefully use nuclear power, and overcome this obstacle.

Re:Almost first post

[AKAImBatman]

The difficulty is in their solar panels. Eventually they collect so much dust that they don't generate enough power. Also, the rovers stay very still at night to conserve power.

Interestingly enough, the engineers nearly had an RTG working for the Rovers. Unfortunately, the outcry about Cassini pretty much killed that. It's too bad, because with an RTG, the power source would outlast the rest of the components by some 50 years!

Re:unmanned missions

[morcheeba]

I hate to argue with your logic, but here goes:

Robots can run basically forever, until something breaks or they run out of juice.
Somehow running out of this consumable is better than a human running out of their consumables (food and air)? If you want to be accurate, there are mechanisms for both to regenerate these consumables -- solar cells and plants.

One unique thing about people (besides their intelligence) is their self-healing characteristics ... if a robot gets a little hole in a hydraulic tube, it'll leak until it's empty. A human would clot that blood and carry on. If a human breaks a leg, you can bet they'd figure out a way to complete the mission with just one leg... I wouldn't give a robot those odds, even if they lost only one of six legs.

But, I agree.. unmanned missions are great, just for totally different reasons: low cost and hence, the ability to many missions to many different areas, each with new instruments designed to test theorys proposed by the results of previous missions. A human mission would blow the whole budget with just one trip.

Re:Almost first post

[Mal-2]

Even with range limitations they're hardly useless. Both rovers landed in relatively fertile areas for exploration, and Opportunity would have still been a big success even if it proved unable to leave the crater it landed in. The main thing that comes to my mind is to find the edges of the ancient ocean and explore there -- partly because tidepools on Earth are teeming with life, and partly because shallow water means fossils (if present) won't be buried very deep. I noticed very early on that the rocks Opportunity was looking at looked an awful lot like tidepool rocks, at least ones from the eastern Pacific shore (the only ones I've seen firsthand). I knew there was good reason for NASA to be REALLY damn sure before announcing there was a lot of water on Mars at one time, but I pretty well was convinced as soon as I saw those distinctive wormholed rocks.

However, it looks like their lifespan will be determined by a few factors, some of which are within human control and some which are not:

1. Dust storms. Seems to me one good one would pretty well take a rover out of service from dust buildup on the panels alone.

2. Equipment failure, particularly the "always on and draining power" type. One has already made Opportunity a little bit gimpy, but I doubt a single such failure would be fatal. Cumulatively, several would just be too much to bear.

3. Shorter and/or darker Martian days as the seasons and distance from the sun change. This won't take out a rover outright of course, but they could compound the prior two problems. At least these events are predictable.

4. The Martian Defense System finally tracks the rovers down and explodes them. Turns out the reason they didn't shoot the first time is they thought it was just another shipment of punching balloons for their nitrous oxide-fueled nightlife. Once they realize we sent ROVERS and not RAVERS, they're going to be mighty pissed off.

Mal-2

Re:Let's hear it again for JPL

[m11533]

Rather than going nuclear, maybe there is an ingenious way to clear the dust off their solar panels, thus extending their useful lifespan indefinitely. I can't imagine there isn't a solution to that problem... maybe something as "simple" as the ability to rotate the panels into a 90-degree position and then shake. Sure seems much simpler than engineering a nuclear based solution.

Re:Let's hear it again for JPL

[silentbozo]

Actually, the nuclear based solution IS the simplest. It's nothing more than a small mass of isotope, a thermocouple, and a pair of wires. It's certainly simpler than a pair of solar panels, or the gyrations you'd need to go through to get rid of the dust coating (electrostatic attraction probably is the factor here.) The Voyager series of probes use these radioisotope-powered thermocouples, and look how long their active life has been.

Re:So why not have wipers on the panels?

[AKAImBatman]

This is an old discussion, so I would recommend you do a search to fully answer your question. Basically though, it came down to several facts:

1. The dust would most likely be statically charged.
2. Wipers would tend to damage the panels.
3. The extreme environment is slowly degrading the panels anyway.

Re:Let's hear it again for JPL

[jwbing]

I remember reading about NASA contemplating some sort of 'blower' device be installed on the rovers. It was cancelled as it would have added more complexity and weight to the system. NASA determined it would be cheaper just to increase the dimensions of the solar panels, thus providing more juice for when they start to get dusty.

Re:Almost first post

[AKAImBatman]

Keep in mind that RTGs are passive devices, not reactors. As such, the radiation dosage will never exceed that of a pound of Plutonium-238. Plutonium-238 gives off a significant amount of radiation (half life of 87 years), but it's all Alpha particles. Since the Pu-238 is emitting Alpha particles, the radiation tends not to even make it through a piece of paper, much less the indestructible casing they pack these things in. Besides, the heat generated by the Alpha particles is what gives the RTG power. Doesn't make a whole lot of sense to let your power escape. :-)

I'm still waiting for the first mission where they use SRGs (Stirling Radioisotope Generators). Those little stirling engines are far more efficient than the heat differential of RTGs. If the tech works out, it could even be a boon for lower powered devices on Earth. I figure that a tiny SRG with about 5-10 grams of Pu-238 or Sr-90 could power your cell phone for 50 years. A laptop (depending on the design) could be powered by 100-600 grams.

Re:Software Issues

[QuantumFTL]

Justin, who names the rocks? You guys are clearly having too much fun in that department.

Actually, my friend Merideth considers herself to be the feature-naming goddess for Spirit, so if /.ers will reply to this post with possible names, I'll put in one of the highest moderated ones for consideration.

No promises though :)

Cheers,
Justin

Rock Names!

[efuseekay]

Here is my list (they are even slightly descriptive)

1. First Post
2. Troll
3. Hot Grits
4. The Insensitive Clod
5. Anonymous Coward

Mozilla!

[njchick]

Mozilla is red like Mars. Mozilla is strong like a rock. Scientists know Mozilla. Mozilla will go to Mars, and followers of Mammon will cower in horror :-)

Won't kill you next to the skin...

[Goonie]

According to the Wikipedia, plutonium emits alpha particles, which can't penetrate the skin. You have to swallow the stuff for it to kill you.

However, you wouldn't exactly want it lying around and getting thrown in landfills, either, so I can't imagine it being used in consumer products any time soon. At least Pu-238 can't be used in nuclear weapons (a big enough piece of the stuff to make a bomb out of would be too hot to be stable).

Name a rock, 'Tux'

[Megaport]

Actually, my friend Merideth considers herself to be the feature-naming goddess for Spirit, so if /.ers will reply to this post with possible names, I'll put in one of the highest moderated ones for consideration.

Hi Justin,
How about we get the ball rolling by naming a rock 'Tux', after the Linux mascot penguin?

Re:Software Issues

[Dirtside]

Well, given the forum, here's some ideas:

- Beowulf
- Soviet Russia
- Natalie
- Dupe (if you find two adjacent rocks that are extremely similar)
- Profit
- Overlord

I think that covers the bulk of common /. humor. :)