Due to budget constraints and to balance the need to support future missions and missions in operations, the request reduces the budget for the Chandra X-Ray Observatory. The Chandra spacecraft has been degrading over its mission lifetime to the extent that several systems require active management to keep temperatures within acceptable ranges for spacecraft operations. This makes scheduling and the post processing of data more complex, increasing mission management costs beyond what NASA can currently afford.
The reduction to Chandra will start orderly mission drawdown to minimal operations.
The request creates two new projects which support international partnerships: the Ultraviolet Transient Astronomy Satellite (ULTRASAT) transferred from Astrophysics Explorer Future Missions and the Laser Interferometer Space Antenna (LISA) transferred from Physics of the Cosmos SR&T.