From space flight now....

Spirit mission controllers did not receive expected data from the Mars Exploration Rover during scheduled communication passes on Wednesday, NASA announced a short while ago.

"Ground controllers were able to send commands to the Mars Exploration Rover Spirit early Wednesday and received a simple signal acknowledging that the rover heard them, but they did not receive expected scientific and engineering data during scheduled communication passes during the rest of that martian day," the Jet Propulsion Laboratory said in a statement.

"Project managers have not yet determined the cause, but similar events occurred several times during the Mars Pathfinder mission. The team is examining a number of different scenarios, some of which would be resolved when the rover wakes up after powering down at the end of the martian day (around midday Pacific time Wednesday).

"The next opportunity to hear from the vehicle is when the rover may attempt to communicate with the Mars Global Surveyor orbiter at about 8:30 p.m. Pacific time Wednesday night (11:30 p.m. EST; 0430 GMT). A second communication opportunity may occur about two hours later during a relay pass via the Mars Odyssey orbiter. If necessary, the flight team will take additional recovery steps early Thursday morning (the morning of sol 19 on Mars) when the rover wakes up and can communicate directly with Earth."

NASA says the next update on the rover's status will be announced at the next daily news conference scheduled for Thursday at 9 a.m. Pacific time (12 p.m. EST; 1700 GMT).

Just out of curiosity, what caused the problems on pathfinder?