Two of the top scientists at the Science Mission Directorate (SMD) at NASA, Alan Stern and John Mather, resigned today to return to their own respective projects. No reason was given in their resignation letters, but speculation is ripe on the internets that it had something to do with the Mars program funding issues. The cost control issues seemed to have been a big part of the problem according to Keith Cowling over at NASA Watch. Alan Stern, who is the Associate Administrator of NASA, will be replaced by Ed Weiler when Stern leaves in a few weeks.
I am not familiar with John Mather, but Alan Stern, who is also the Principal Investigator of the New Horizons mission to Pluto, is well respected within the planetary science community and was considered a great asset at NASA headquarters. He will be sorely missed there as the Mars Program funding issues continues to heat up and the Outer Planets flagship mission will be selected later this year. His leadership was greatly valued.