Michael Griffin has asked a congressman for legislation to allow "permanent" employees to accept incentives to move from permanent to term appointments.
As an example for the need for such a flexibility, in 2010 NASA will need to get rid of people currently working on Shuttle who are much needed now. A bill proposed would give 25% of salary or $25,000 which ever is less, for every year that goes by. Terms can be terminated easier than permanent employees after their "term" runs out. As an example of an incentive, if a shuttle worker signed up today (19 April 2007) then the incentive would be $25,000 * 3 or $ 75,000. This could really make sense for a permanent employee who is nearing retirement.
Updated 4 June 2007