The Rovers That Just Won't Quit 299
smooth wombat writes "Like the Energizer bunny, the two martian rovers just won't quit. Spirit, after climbing to the top of Husband Hill during the past year, spent two months examining rocks at the top of the hill and scientists confirmed that those rocks were similar to rocks found along the side of the hill indicating that Husband Hill is probably the result of an impact crater.
It will take about two months for Spirit to make its way down the hill after which the next target will be a feature called Home Plate located about a half mile away.
Opportunity is exploring the northern rim of Erebus Crater, the largest crater between already-explored Endurance Crater and its next destination, Victoria Crater.
The rovers were only supposed to last three months but have been operating for almost two years. NASA has also released a 360 degree panorama of images taken by Spirit as it explored Gustav Crater."
Read this book. (Score:5, Informative)
I read Roving Mars [amazon.ca] a few months ago. It was written by Steven Squyres, the principal investigator for the Mars missions. A very good book with some behind the scenes scoop on the politics and squabbling involved in getting these things build and sent. Highly recommended.
Larger version... (Score:5, Informative)
Re:One thing no one is really talking about... (Score:5, Informative)
Gustav Crater? (Score:5, Informative)
Re:Read this book. (Score:5, Informative)
Re:conversion error? (Score:5, Informative)
One of the designers gave a presentation to our conference the day after they landed. It's easy to say they sandbagged their estimate, but they have had a host of challenges such as
So yeah, say they sandbagged it, but in reality, it was entirely possible that they could have worked only for a day (or not at all) and they would have been ostracized for being incompetent when they actually did a fine job. Congratulations to them.
Re:Any ideas? (Score:4, Informative)
Re:Larger pictures? (Score:3, Informative)
- Opportunity panoramas [nasa.gov]
I'd assume all there are available in anything from small to huge images in typical NASA fashion.
Re:Hmmmm (Score:3, Informative)
Also the probability of finding something out of the ordinary get's higher with more data. If on 1 in a 10000 pictures would capture some rare kind of rock in mars, with the extended lifetime of the rovers it will be more probable to find that rock, among the data.
Great Link for Rover Updates (Score:2, Informative)
Cornell/Athena Updates (Pops) [cornell.edu]
Re:conversion error? (Score:5, Informative)
There was no landing foam. There were inflated bags that cushioned the impact as the lander bounced. The bags had cords attached to them that were retracted after landing to pull the deflated bags under the lander out of the way. The retraction didn't work 100%, and there was concern that the rover's wheels would get tangled up in the bags or the cords (which turned out not to happen).
The rover actually got stuck on mostly flat terrain. It was crossing some low wind swept dunes which the wheels eventually just dug into (think a car on the beach). By wiggling back and forth they were able to back out, and they added some movement rules for the auto drive that if a lot of slippage occurs the move stops so as not to dig so deep into loose sand.
Re:One thing no one is really talking about... (Score:4, Informative)
They aren't over engineered for the environment they were expected to operate in. Our understanding of the martian environment led the engineers to believe that the solar panels would become dirty quickly. I'm sure cleaning systems were considered but a desision was made to have rovers that lasted 3 months without a cleaning machanism. Turns out we didn't understand the martian environment all that well and wind is keeping the panels clean enough to power the rovers. That's just shear luck.
As for the other parts of the rovers out lasting their usefulness - well that just goes to show how good some areas of engineering have become. Yes they could probably have fitted wheel bearings that would seize after 3 months but as they would weigh the same as (or damn near) the ones that have lasted 2 years a desision was made to fit the better bearings. There will always be one weakest component in this case our best guess at what is was was wrong. I'd be interested to know what part eventually fails and kills the rovers. If nothing else this is an interesting experiment into long term rover deployment. I am sure the engineers are getting plenty of interesting telemetry back on what is failing on the rovers.
Happy Martian Birthday Spirit! (Score:3, Informative)
Re:finding same old rocks (Score:3, Informative)
Re:Low Resolution Images.... (Score:5, Informative)
Re:The other side of the crater... (Score:2, Informative)
The bear went over the mountain, the bear went over the mountain...
Yes, I work with a bunch of noobs.
Re:One thing no one is really talking about... (Score:3, Informative)
1) dust
2) batteries not maintaining a charge
3) Cold cracking circuit boards/frezing batteries at night
4) not enough power in the mars winter to keep from waking in safe mode each morning
5) accedents (getting stuck)
6) Some other mechanical failure
7) landing somewhere trapped or unable to get off the pad.
This is what I recall from reading articles about the project early on. I hoped they would get to mars. Move around some. get stuck/figure out they were trapped. Continue to send data back like the Lunar probes and eventually earth would stop listening.
Needless to say this is much better than I had hoped. But I am confident that they will both die/get stuck unexpectedly over time. When things NASA makes do not die when expected, they do tend to last for years. I would not be too shocked if one of these rovers was used to help monitor weather conditions in a limited way for the next 20 years.
Re:One thing no one is really talking about... (Score:4, Informative)
Very true. The entire MER program was mass-constrained from the get-go. They barely fit on the launch vehicle. At some points during the design cycle the mass margin was negative, and the systems engineers had to hunt around for things to take off. There was no room to spare for over-engineering, because there just wasn't any spare mass for anything other than the bare minimum to achieve the mission. I speak from direct knowledge here, because I sat through the debates about whether or not to have two transponders (final decision: one - the SDST was considered reasonably reliable), and similar debates about the solid-state power amplifiers (the final word I heard was two SSPAs, due to their potential for failure, but that may have changed after I left the program). We used to joke that the only redundant things in the entire systems were the heaters and the SSPAs.
Re:conversion error? (Score:3, Informative)
1) It wasn't a buffer overflow. It was a filesystem error caused by trying to add the 32,769th file to a file system which uses 16-bits to track files.
2) They didn't upload a new software version. The uploaded a script that could operate on the flash system without mounting it, so they could delete enough files to mount the flash system. They then had to re-upload some files that had been corrupted. They didn't have to upload a new OS, since it really didn't do anything wrong. The error was in continuing to upload files to the rover after a script to delete old files had failed to upload. They knew there was a file count limit, but the guy that was responsible for uploading the delete script failed to inform the other guys uploading files that the delete script upload failed and there wasn't as much free space as he had previously told them. I think they did tweak some settings, though, so that a file system error would not reboot the whole machine, but would just shut down the process associated with the error.
3) The concern that the rover would get tangled did result in a pretty long delay while they tested an alternative route to get off the platform. So the rover was effectively "stuck" in place (didn't move) although it wasn't literally stuck in place (couldn't move).
Re:All you fans of sterile deserts say WHOOOP!!! (Score:2, Informative)
About as much as we spend on Iraq every week.