Two years ago this week, Spirit—the
first of NASA’s twin Mars Exploration Rovers—touched down on the Red Planet,
inaugurating a period of unbounded surface exploration that continues even as
we speak. The sheer amount of Geek Trivia (and, of course, science) provided by
this mission could fill dozens of articles—indeed, Spirit has proven so remarkable that scientists renamed asteroid
37452 in its honor—but we’ll try to hit the high spots.
While a number of NASA missions have made photographic
history, Spirit has made its own historic
contributions to the astronomic photographic archives. On Jan. 6, 2004, the
rover’s panoramic camera (or “pancam”) took the highest resolution
image ever captured on the surface of another planet. (It was also the first
color photo taken by Spirit.) Twelve
million pixels (4000 x 3000) imbued the
wide-frame image of the Sleepy Hollow crater.
One month later, February 6 marked the first grinding of a
rock on Mars using artificial, mechanical means. Spirit‘s Rock Abrasion Tool (RAT) ground out a 2.65-millimeter deep
impression on a rock sample designated Adirondack,
illuminating the inner layers for observation by the rover’s spectrographic
On March 9, 2005—after more than a year on the Martian
surface—Spirit received some unexpected
ad hoc maintenance from Mother Nature, combined with a rather momentous
scientific opportunity. The rover’s solar panels suddenly jumped from roughly
60 percent efficiency to more than 90 percent.
The cause was a flyby from a Martian dust devil, which
likely swept a year’s worth of grime from Spirit‘s
solar panels and offered scientists a chance to review accidentally captured
data on the rarely seen Martian meteorological phenomenon.
Yet, for all its myriad and marvelous technical achievements
(to say nothing of help from the winds of good fortune), not even so fine an
instrument as Spirit is beyond the
need for tech support. On Jan. 21, 2004—less than three weeks after touchdown—Spirit suffered a crippling technical
glitch that baffled operators and engineers for days, despite the deceptively simple
WHAT TECHNICAL GLITCH CRIPPLED THE MARS SPIRIT ROVER MERE DAYS AFTER TOUCHDOWN, BUT HAD A DECEPTIVELY
SIMPLE TECHNICAL SOLUTION?
What technical glitch crippled the revered Mars Exploration
Rover Spirit mere weeks after its
deployment on the Red Planet—and what unexpectedly simple solution allowed the
plucky probe to resume its historic explorations unimpeded?
On Jan. 21, 2004, the Spirit
rover crashed. Not physically, but computationally—ceasing all communications
with NASA mission control. A day later, it sent out an interplanetary error
code, presenting its operators with the equivalent of Windows’ dreaded Blue
Screen of Death.
Like any good tech, Spirit‘s
controllers rebooted the system—only to find the rover stuck in an error loop,
constantly reloading the onboard flight software and then crashing before the
boot cycle was complete. (For the record, Spirit
and its twin, Opportunity, both use
the VxWorks embedded operating system found on many recent space probes, so
don’t go blaming this mess on Linux or Windows.)
Again, following the universal tech support playbook,
engineers instructed Spirit to boot into “crippled mode,” the rough
equivalent of Windows Safe Mode. Crippled mode meant Spirit was operating using
only RAM, rather than its onboard 256-MB flash memory systems.
Once in crippled mode, the rover became responsive,
suggesting that the problem had to do with the flash memory. However,
diagnostics and deduction illustrated that the flash memory module was
physically fine. This was a software bug—and apparently a major one.
NASA engineers immediately launched into a series of
software diagnostics that, ironically enough, actually made the problem worse.
Only after making Spirit less
responsive with their repair efforts did NASA realize the simplicity of the
problem: Too many files on the file system.
The software diagnostics had actually aggravated the
situation by dropping more files on the system. Most of the culpable files were
leftover in-flight data that were no longer necessary.
A quick batch of deletes, a software patch to perform some
regular garbage collection, and a complete reformat of the flash memory—in tech
speak, smoke the system and load a clean image—put Spirit back at full
strength. Engineers applied the same remedy to the Opportunity rover before it had a chance to lock up, and that probe
has never suffered from the same problem. It just goes to show that sound tech
support principles—and Geek Trivia—apply no matter which planet you’re on.
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The Quibble of the Week
If you uncover a questionable fact or debatable aspect of
this week’s Geek Trivia, just post it in the discussion area of the article.
Every week, yours truly will choose the best post from the assembled masses and
discuss it in the next edition of Geek Trivia.
This week’s quibble comes from the December 7 edition of
Geek Trivia, “Worth
a thousand worlds.” TechRepublic member Allvord tried to bust me on some incorrect use of photographic
“Shouldn’t that be a composite photo—or mosaic, when multiple images are pieced together
to make a whole?”
For once, however, I used my terms correctly, and member Erich.l.tucker quickly jumped to my
“In the article, component
is referring to the individual photos taken by various satellites and space
probes—not the resulting combination of those pieces. Those individual photos
are the components that would make a complete or composite image.”
Now that we’ve got that cleared up, thanks for the
responses, and keep those quibbles coming.
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The Trivia Geek, also
known as Jay Garmon, is a former advertising copywriter and Web developer who’s
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books, technology, and all things geekish or subcultural.