Talk about a rough week! Spirit experienced a few software glitches, command sequencing errors, and particularly tough terrain from April 8 through April 15, 2005. After problems were solved, the rover picked up and continued exploring the "Columbia Hills."
Sol-by-sol summaries:
Sol 449 (April 8, 2005): Spirit has been attempting to climb steep and rock-strewn slopes in the Columbia Hills. The rover automatically went into safe mode when the flight software rebooted on sol 449. Spirit then waited to get commands from engineers back on Earth.
Sol 450: An overlooked condition caused more headaches for the beloved Spirit. When the software rebooted on Sol 449, Spirit lost knowledge of where its high-gain antenna was pointed. When Spirit tried to use the antenna during sol 450's uplink without knowing where it was pointed, a fault condition resulted. Since Spirit could not figure out where to point the antenna, the rover missed the uplink for the day.
Sol 451: In order to get out of the fault condition, the rover uplink team came in on the weekend, and put the spacecraft into safe mode, a status in which only systems vital to the rover's health operate. The team commanded Spirit out of the high-gain antenna pointing error and left Spirit in auto mode. Auto mode occurs when the spacecraft is not running instructions from the Earth, but rather is taking care of itself.
Sol 452: Because Spirit was in auto mode, with no sequence of commands running, Spirit just relaxed and took care of itself on sol 452.
Sol 453: Before Spirit could drive, the rover needed to take fresh images of the surrounding terrain. Sol 453 was spent taking these images in preparation for driving on sol 454.
Sol 454: Spirit made another attempt to drive uphill. The drive did not go very well. Spirit slipped quite a bit. Engineers and scientists decided to try a different tactic for Spirit to climb this hill.
Sol 455: Rover team scientists and engineers decided that they had tried long enough to coax Spirit up this hill at this location and that it was time to try another approach. Instead of going up, Spirit would go down and cross the slope a bit. They will send Spirit cross slope until an easier path to the summit is identified.
Sol 456 (April 15, 2005): This sol's plan consists of a small drive forward to a soil target where Spirit will use its front wheels to churn up a bit of Mars. The plan is to then examine this soil with instruments on the robotic arm.