Chandra X-ray Center Manager’s Report

Mark Weber

Reporting period: November 2022 – October 2023

The Chandra X-ray Observatory has carried out more than 24 years of highly successful and productive science operations. Chandra is unique in its capability for producing the sub-arcsecond X-ray images that are essential to accomplish the science goals of many key X-ray and multi-wavelength investigations in current astrophysical research. The Project is looking forward to many more years of scientific productivity.

The High Resolution Camera (HRC) returned to normal science operations in April 2023, following a low-voltage power supply anomaly in February 2022. The successful return to operations was the result of extensive analysis and planning by the HRC instrument team, SAO engineering staff, and Chandra mission planning and other operations staff.

A complex, multi-year effort—including a very comprehensive program of design analysis and ground testing—culminated in the Processor Electronics Assembly (PEA) flight software patch for the Aspect Camera Assembly (ACA). This patch effectively rolls back eight years of ACA degradation for tracking of faint guide stars, and it will make a noticeable impact on the all-sky science capability of Chandra going forward.

The Chandra Observatory continues to function at near pre-launch expectations with no significant or unmitigated subsystem issues. Incremental changes in some component performance continue, in line with pre-launch predictions and without hindering operations. The performance of the spacecraft thermal insulation continues to trend downwards in a predicted fashion; however this is—and has been for the majority of the mission—mitigated by thorough mission scheduling, sustained with support from increasingly sophisticated software scheduling tools. The gradual accumulation of molecular contamination on the UV filter that protects the ACIS detector reduces ACIS’s sensitivity to low-energy (below ~ 1.5 keV) X-rays. Chandra has maintained its mission-long run of high observation efficiency, collecting data on science targets for ~90% of the available observing time (maneuvers, instrument setup, etc. necessarily take up some observing time).

Scientists worldwide responded to the call for proposals for Cycle 25 observations by submitting 408 proposals, requesting 4.65 times more observing time than is available during the cycle. The dual-anonymous peer review of proposals, which was held in June, approved 103 observing proposals and 21 archive & theory proposals.

The CXC conducted the annual Chandra summer science workshop in August this year on the subject of High Resolution X-ray Spectroscopy. The in-person component was held on the campus of the Massachusetts Institute of Technology in Cambridge, Massachusetts.

The CXC hosted this year’s NASA Hubble Fellowship Program (NHFP) symposium in Cambridge in September. Information about the NHFP is available at

The Chandra Press Office has been active in issuing image releases, science press releases, and other communications of Chandra research results. A complete listing is available at Information about the Chandra Observatory and the Chandra X-ray Center can be found at