Spirit, one of the two Mars rovers that landed way back in January 2004, is now permanently stuck in the dirt. Had to happen sometime. But, it’s still able to do good science while stationary. Spirit will now help scientists at the JPL learn more about Mars’ core by measuring small variations in its precession about its axis. From the article:
Mars is rotating around its own axis and orbiting the Sun. With the rover stationary, the radio’s only motion will be the motion of Mars. Because the scientists already know the specifics of the red planet’s orbit, they’ll be able to use Spirit’s radio signal to hone in on how the planet spins around its own axis.
“Mars wobbles, or precesses, as it spins,” says Bruce Banerdt of NASA’s Jet Propulsion Laboratory. “We’ll measure that wobble by looking at the Doppler shift of Spirit’s radio signal.”
