Mars Rover Spirit Back Online

Skyshadow writes "Just in time for the arrival of its twin, the Spirit Mars Rover is back in working order. Programmers at the JPL have traced the problem to the rover's flash RAM, which it uses to maintain its filesystems. They are using a ramdisk in the rover's RAM to bypass the bad flash memory, and are working on a workaround for the bad flash. Good news, but the rover is still potentially weeks away from full operational status."

Comments

heh... /. was right!

[Smitty825]

During all of the "Spirit is broken" columns, I kept reading /. comments saying that it was likely a memory error due to the non-consistent errors...I guess a million monkeys with a typewriter can be correct :-)

The epitome of remote administration

[Faust7]

Engineers guessed that Spirit's troubles were in its Flash memory and set about sending the rover a complex series of instructions to see if they could get it to bypass the corrupted memory. Theisinger said engineers sent Spirit a command just before its daily "waking up," telling it to shut down and restart in what is known as "cripple mode," using RAM instead of Flash for its start-up instructions.

Some people may take this sort of thing for granted, but I for one find it remarkable that we can essentially reboot and perhaps even fix a system that is on a whole other planet.

Just wait until we have Interplanetary, Interstellar, Intergalactic Remote Desktop. I'm only half-joking.

Re:The epitome of remote administration

[blincoln]

It's all good until tech support says, "So... Do you have a boot disk?" :-)

You joke, but newer servers can do this remotely too.

We have a bunch of Compaq servers at work, and one of the really cool features of the remote administration software is that you can send a virtual floppy image to the machine from anywhere in the world that can open a web browser connection to the server's remote administration board.

A few months ago one of our servers in Denver died, and I had to boot it up in Windows 2000's command prompt only safe mode... but the local admin password had never been written down. I was able to make virtual floppy images of a tool that resets the local admin password, send them over the wire, and boot off of them from the remote administration system.

Okay, it's not fixing a super-expensive robot on another planet, but I thought it was pretty cool.

Static Discharge?

[seven of five]

Is there a chance that the problem could've been caused by electrostatic discharge? Rover bounces on rubber airbags on sand, bags fold up, Rover rolls off, Rover touches rock - zap!??

Cosmic rays...

[bc90021]

...will apparently cause one out of every trillion bits on Earth to flip randomly... I guess with less of an atmosphere, it is a bigger problem on Mars! ;)

Re:Cosmic rays...

[shadowmatter]

Funny you mention that. I'm taking a class on design of digital systems at my university, and my professor works for JPL. He helps design the control systems onboard space vehicles such as the Mars rover. Anyway, a majority of the class grade is based on an end-of-the-quarter project, which we complete in groups of 2 to 4. On Wednesday he expressed interest in a group developing some sort of redundancy for FPGAs that would be suitable in spacecraft. You see, on Mars, you're not shielded from huge doses of radiation as you are on earth. A healthy dose of radiation bombardment could easily reprogram an FPGA chip on the surface of Mars; ASICs chips are used to overcome this problem.

Maybe he was gung-ho about anti-radiation redundancy because he already knew the likely problem of the Spirit. Who knows?

- sm

Nice

[Omega1045]

I have a friend who works in the field. Space travel hoses electronics bad. Triple redundancy and over-engineering is the name of the game. This is nice to hear. I would imagine that something went wrong intransit or on-landing, but they can keep going,

Information on the MER hardware.

[elrond1999]

Ive been unable to find any hard information on the design of the MER memory systems. If anyone can point me to a technical brief id be very happy.

From what ive pieced together the MER system is something like this:

One RAD6000 powerpc cpu.
Connected via probably compact pci to 128 mb of ecc sdram.
256 mb of flash. No info on what make of flash, but likely Intel since they are the biggest. There was some info from the press conference that there are actually two flash chips and that the flight software is redundantly stored on each. So does this mean that there is actually 128mb of redundant flash? Also it was said that they had problems even with the redundancy, could they possibly have overwritten something? We all know that even a redundant raid does not stop filesystem corruption.

No information on how the flash is connected, parallell / serial? How the redundancy works?

Btw, I guess flash is rather radiation hard since they require 10 - 20V to erase / write.

We learn from our mistakes...

[Chordonblue]

So... I wonder if they'll consider validating MRAM more quickly if Flash is found to be more error prone.

You know how NASA works. The Space Shuttle running on 486's and whatnot. I understand the science behind that reasoning, as sad as a 66 MHz processor seems to us geeks nowadays, but I wonder if MRAM will prove more flexible and stable for future space missions.