This is a website about roving on Mars...
I was fortunate enough to be part of the team that designed, built, and drove the first Mars rover--Sojourner--on the surface
of Mars during the Mars Pathfinder mission in 1997.
That story is chronicled in my new book, "Sojourner: An Insider's View of the Mars Pathfinder Mission."
I am again privileged to be a participant in the next Mars mission--called Mars Exploration Rover, or MER--that will land
two rovers on the Red Planet in January 2004.
I will be periodically recording my observations as the MER rovers explore the terrain of Mars during the next few months...
Thursday, February 5, 2004
Spirit gets back on its feet, while Opportunity begins to explore...
We're now up to sol 32 on Spirit. Wow! We've been living on Mars time for a month now. By this time on Pathfinder, the Sojourner
team had rebelled against Mars time, but we're still going strong.
6:07 am pst
The Spirit science team has been impatiently waiting to resume their science observations. I don't blame them. Science has
been forced to take a back seat to the engineering troubleshooting necessary to getting the Spirit rover fully operational
again. (I personally would rather be planning science sols rather than tracking the engineering sequences we're using to
investigate and correct the anomaly.)
The problems on Spirit have been traced to memory use in the rover's RAM as the number of distinct files stored in its "flash"
memory increases. When the RAM fills up, the rover stops working. By deleting a number of files, we were able to get the
rover to operate normally.
Today (sol 31) we told the rover to take it easy, shutting off by 1:30 in the afternoon and not waking up overnight to talk
to us. The idea was to get the batteries fully charged, and to let the rover electronics cool off as much as possible.
This is all in preparation for re-formatting our onboard "flash" memory tomorrow. Once we got the rover stable,
we were able to determine that some of the flash memory had been corrupted by the sol 18 anomaly. So, just like you might
do on your own computer, we're going to erase and reformat our memory to clean things out. Since this process will take many
hours and be monitored closely from the ground, we're going to get an early start on sol 32, waking the rover up at 6 am local
Mars time. By cooling off the rover on sol 31, we ensured that Spirit could stay powered up all day on sol 32 without overheating.
The reformat went without a hitch! Spirit is healthy and ready for the rest of its mission.
Let's get back to doing science!
Meanwhile, on the other side of the planet...
Opportunity also checked out as very healthy after its bouncy landing. The only nagging problem is a heater for one of the
joints of the rover's robotic arm, one of several heaters used to warm up the arm if we want to operate it in cold nighttime
temperatures. Unfortunately, this one heater is coming on overnight even when we don't want it to, and it's running down our
batteries a bit. This isn't really an issue early in the mission, but as dust piles up on the solar arrays and the seasons
change, we will wish we had that extra energy to keep the inside of the rover toasty at night. The team will keep looking
for a solution.
Opportunity drove off the lander on sol 7. Even being cautious not to stumble into Spirit's memory woes, egress preparations
went much more smoothly for our second rover. Due to Opportunity's side-petal landing, all of the airbags in the forward
direction of travel were fully retracted out of the way.
Once Opportunity had driven off the lander, people on the team started to say "12 wheels on dirt!" to symbolize
the two MER rover successes. I reminded them that there is one more rover on Mars, one that's been waiting since 1997. While
everyone was drinking champagne to celebrate, I raised my glass and said, "18 wheels on soil!"
Since Opportunity managed the unlikely achievement of landing inside a small crater, the horizon is a bit higher than if we
had landed on a flat plain. And with the very sandlike terrain, the image mosaic of the post-egress photos creates an optical
illusion, with the rover and now dead lander apparently sitting on a Little Prince-sized planet.
I just saw a fantastic picture! It was taken with the rover's Navigation cameras back on sol 4, but we just got it transmitted
back to Earth today (sol 12). The image was taken while opportunity was stood-up on the lander, at the rover's hight elevation
for many sols. The rover was standing up high enough at this point to see some of the terrain beyond the walls of the crater
we landed in. And out there, to the southwest, there appear to be two objects. One is rather dark and perhaps rectangular
or conical. A little ways to the right of this object is a flatter, longer white shape. Most people on the team who've seen
the photo think we're looking at spacecraft backshell (separated from the lander in the final minute before landing) and its
attached parachute. It's tantalizing...we'd love to get a higher resolution image using the rover's Pancam cameras, but now
that we've driven off the lander, the rover isn't tall enough to see over the lip of the crater we're sitting in. We'll just
have to wait until it's time to drive out of this crater, and try to get another shot then...
I'll make additions to this site as often as living on Mars time and exploring an alien planet permit...
Links to other Mars-related websites:
Mars Pathfinder Mission archive
Mars Exploration Rover Mission
Mars24: Keep track of Mars time at the MER landing sites