How real is this?
One command sequence per day:
The Deep Space Network that is used to communicate
with all spacecraft is very busy. NASA scientists
only had one window per day to talk to Sojourner.
Command sequences, not steering:
Because radio signals take at least 20 minutes to
reach Mars, you could never steer the rover in real
time. Rover scientists and engineers spend each
day studying photos from the previous days to plan
the days operations, then upload a sequence of commands.
Only a week to drive: the Sojourner
rover’s nominal planned mission lifetime was
about a week. It actually continued to operate for
12 weeks. Newer rovers are planned to operate for
You can learn more about rovers in our Rovers
Tour. Or you can go to the Mars
Tour Home and explore even more... Volcanoes, Canyons, Floodplains.
Finally, if you want to do something a little deeper, try our Mars
The MER Rover site at JPL
The Athena site at Cornell
The Mars Pathfinder site
To Mars With
MER (Passport to Knowledge)
Red Rover Goes to Mars