For Scientists: The Long-Term Plan

This is the current Year-1 Long-Term Plan (LTP) for IXPE, assuming a 2021-Dec-09 launch. The Science Advisory Team also requested transient targets to be added when and if they become bright. At such time, the LTP will be adjusted, attempting to minimize the impact on the overall plan; however, nothing is guaranteed. The current LTP can accommodate the addition of approximately a half-dozen transients. Should there be a lack of transients in the coming year, additional time and/or targets will be added to the plan.

IXPE is telemetry limited for bright sources and this requires that observations be handled slightly differently from the way most X-ray missions operate. If IXPE is observing a bright source that could potentially fill on-board storage, we shall divide the observation into multiple segments.


SG: This is a segment number. If it is zero, then the observation has not been segmented.

Name: This is a common name for the target.

Start: The Year-Month-Day the observation will begin. The observations ends just before the next target begins.

buffer: This is an estimate as to how much data will stll be on the spacecraft when the observation ends in MB. The on-board storage can hold just over 5500 MB and when planning we keep this number below 4000 MB.

SG NameStart buffer
0Cas A2022-01-100
0Cen A2022-01-280
0Her X-12022-01-300
14U 0142+612022-01-310
0Her X-12022-02-050
24U 0142+612022-02-060
0Her X-12022-02-120
34U 0142+612022-02-130
0Her X-12022-02-160
44U 0142+612022-02-180
0Cen A2022-02-223149.7
0Her X-12022-02-243105.7
1Sgr A complex2022-02-252653.2
0Her X-12022-02-272599.6
0Mrk 5012022-02-282460.3
2Sgr A complex2022-03-01650.6
0X Persei2022-03-113551.9
3Sgr A complex2022-03-131289.7
0Mrk 5012022-03-241153.9
0GS 1826-2382022-03-251239
0S5 0716+7142022-03-2745.5
0Mrk 5012022-04-010
0GRS 1915+1052022-04-020
0Vela Pulsar2022-04-080
0Mrk 4212022-04-28315.8
0Cyg X-12022-04-292703.5
0Vela X-12022-05-163226.2
0BL Lac2022-05-221552.6
0Mrk 4212022-05-301841.2
03C 454.32022-05-311400.9
03C 2732022-06-02957.7
0Cyg X-22022-06-052821.5
0Mrk 4212022-06-073120.6
01ES 1959+6502022-06-083094.1
03C 454.32022-06-082653.9
0Mrk 4212022-06-112940
03C 2792022-06-122497
0Mrk 4212022-06-142782.9
01ES 1959+6502022-06-152760.3
03C 2732022-06-162317.3
0Mrk 4212022-06-182614.3
0Mrk 5012022-07-060
0IC 4329A2022-07-070
01ES 0229+2002022-07-180
03C 2792022-07-260
0GX 301-22022-08-020
0Circinus galax2022-08-070
01RXS J170849.02022-09-170
0Mrk 5012022-10-080
04U 1626-672022-10-100
01ES 1959+6502022-10-130
0Mrk 5012022-10-140


This is the pre-launch plan. Expect an update sometime in late Dec.

Currently the plan does not include a 2nd look at J0211+1051 nor a long observation of SN 1006. These will be added as the year progresses.

Should commissioning finish early then the observation of Cas A will begin early. If this happens, we will add an observation of J0211+1051 immediately following the observation of Cas A and preserve the rest of the LTP.

The precise phasing of Her X-1 observations will be adjusted relative 4U 0142+61 to give good coverage of the 35 day cycle of Her X-1.

It is likely that the observation of Cyg X-1 will be delayed by about 2 weeks and the following targets moved earlier. This will allow coordinated observations with XL-Calibur.

+ NASA Privacy, Security, Notices | Last Updated: October 18, 2021 | Author/Curator: Mitzi Adams, mitzi.adams @