Chandra X-ray Center (CXC) Manager’s Report

Mark Weber

The Chandra X-ray Observatory is in its 27th year of highly successful and productive science operations. With its unique capability for sub-arcsecond X-ray imaging, Chandra provides essential information for accomplishing many X-ray and multi-wavelength investigations in current astrophysical research.

Chandra took part in NASA's 2025 Astrophysics Division Senior Review. In recognition of the superb performance by the Chandra X-ray Center's staff in operating Chandra and serving the scientific community, and of Chandra's continuing contributions to astrophysical knowledge, the Senior Review panel rated the Chandra program as Excellent / Very Good. Concerning Chandra, the panel's report stated, "Now is arguably the most compelling time for Chandra to operate, joining the Hubble Space Telescope and JWST to enable sub-arcsecond observations across the electromagnetic spectrum from mid-infrared to X-rays. This set of three flagship observatories is a powerhouse that will provide unparalleled scientific potential that will not be superseded for many years."

Chandra observing time continues to be highly sought after. Scientists worldwide responded to Chandra's Cycle 27 Call for Proposals with 299 observing proposals, requesting 4.3 times the effective available observing time. No Theory nor Archive proposals were solicited in this call, which typically result in 70–90 additional proposals. Proposals to do research on Chandra archival data may now be submitted through the NASA ADAP call. The dual-anonymous peer review held in May–June approved 102 observing proposals.

The Chandra Observatory continues to function at or near pre-launch expectations. Incremental changes in the performance of some components continue, generally in line with pre-launch predictions and without hindering operations. The performance of the spacecraft's thermal insulation continues to decline gradually; however, this trend has been mitigated by careful mission scheduling, aided by 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. To protect its instruments, Chandra cannot observe during passages through Earth's radiation belts, and spacecraft maneuvers, instrument setup, and other procedures necessarily take up a small amount of the available time. Nevertheless, Chandra continues to maintain its observing efficiency near the mission-long average of ~70%.

The High Resolution Camera spectroscopic detector (HRC-S) experienced a power supply anomaly in October 2025. Instrument operations were safely suspended for investigation, while ACIS science operations continued. The HRC imaging detector (HRC-I) and shared electronics were successfully checked out and returned to science operations in January 2026. At the time of this report, the analysis of the anomaly and of the potential for a return to science are ongoing.

In the past year, accolades have continued to accumulate for work at the Chandra X-Ray Center. Dr. Ian Evans and Dr. Daniel Patnaude were each recipients of Smithsonian 2025 Secretary's Research Prizes for their research. Dr. Kim Arcand won the Astronomical Society of the Pacific Klumpke-Roberts Award for 2025, awarded to an individual or individuals who have made "outstanding contributions to the public understanding and appreciation of astronomy." The Chandra 25th Anniversary Digital Campaign team also won the Smithsonian 2025 Excellence in Digital Impact Award for their efforts to bring the celebration of Chandra's 25th anniversary (in 2024) to a huge audience across a wide range of digital venues and media. Additionally, the documentary Listen to the Universe, developed out of Chandra's leading role in the sonification of astrophysical data, has won twelve industry / film festival awards.

Meanwhile, the Chandra Press Office has been very active in issuing image releases, science press releases, and other communications of Chandra research results. A complete listing is available at https://chandra.si.edu/press/. Additional information about the Chandra Observatory and the Chandra X-ray Center can be found at https://cxc.harvard.edu/.