In the following we list the most important dates relating to the upcoming XMM mission.
| Date | Event |
|---|---|
| 23.09.1998 | Release of XMM Users' Handbook (Issue 1.0) |
| 30.09.1998 | First XMM Workshop at ESTEC |
| 19.01.1999 | Release of AO-1 |
| 19.01.1999 | Release of XRPS software for proposal submission |
| 19.01.1999 | Release of XMM Users' Handbook (Issue 1.1) |
| 17.04.1999 | 00:00 UT - Deadline for AO-1 |
| 02.08.1999 | SAS release |
| 21.01.2000 | XMM launch date |
| 02.07.2000 | Approximate start of XMM open time observations (TBC) |