Director's Log

Pat Slane

The past year of Chandra activities has included grand celebrations of the long-term mission success, new science results that highlight both the legacy value of Chandra and its contributions to newly unfolding areas of investigation, and continued innovation in the development and improvement of operational schemes. At the same time, continued concerns on funding have escalated from the threatened decommissioning of the observatory over a year ago to a period of painful uncertainty for not only Chandra, but for broad scientific efforts within and beyond our domain of astrophysics. The result has been a dedicated effort to plan for continued and future operation of Chandra while waiting for actual knowledge of what that future holds.

As a quick summary, this year started with NASA's Senior Review of operating astrophysics missions, with proposals submitted in late 2024. Based on the budget guidelines—which were taken from the 2024 President's Budget Request that, many will remember, called for Chandra's decommissioning—three scenarios were put forth in the Chandra proposal. These included a "minimal-cost mission" that would remove many service functions of the observatory but continue to carry out science observations; the full mission, that we all recognize as Chandra over the years; and a close-out plan. The Senior Review panel concentrated on the minimal-cost issue and Chandra received an overall Excellent/Very Good rating, with the panel also calling out for support of additional elements of the full mission if sufficient budget resources are available. NASA's decisions about the future of its operating missions will be informed by these results, but they are likely to be constrained heavily by the appropriated funding. As I write, the situation remains unsettled—though with promising signs due to efforts within the community, from the public, and beyond.

Parallel to this unfolding situation, the Chandra community has remained very active. Celebration of twenty-five years of Chandra science continued with a highly successful and engaging symposium at the end of last year, special sessions at the APS meeting, and a number of dedicated colloquia. Chandra publication rates remain robust. The Cycle 27 proposal call was highly oversubscribed, and the resulting approved program is bursting at the seams with exciting new science initiatives. As we await news about Chandra's continued operation, the current health of the observatory remains excellent, with no known technical issues that will prevent efficient and outstanding performance through the current decade—and likely well beyond.

In closing, I would like to mention departures of two long-standing members of the Chandra project.

Steve O'Dell has retired from his recent position as Chandra Project Scientist at NASA/MSFC. Steve has been part of the Chandra project since long before launch and has contributed to a wide range of elements that define the mission as we know it. I've worked with Steve from the first moments I started on what was then AXAF, and I have valued his keen insights, incredible attention to detail, and congenial working manner over these many years. More recently, that collaboration has extended to mutual work on IXPE, for which Steve also had a long leadership role. Steven Ehlert has stepped into the role of Acting Project Scientist for Chandra.

Claude Canizares has also retired. Claude wore multiple hats for the Chandra team, acting as the Principle Investigator for the High Energy Transmission Grating Spectrometer and as CXC Associate Director for MIT. His fingerprints are found all over X-ray astronomy, with multiple instrumentation developments that helped define the field. The depth of his insights—on technical, scientific, and programmatic issues—were perfectly complemented by the steady and thoughtful manner with which he approached them, and Chandra bears the imprint of his significant contributions. Herman Marshall has succeeded Claude as CXC AD for MIT.

I'm sure I speak on behalf of the entire X-ray community in wishing both Steve and Claude a happy and productive retirement.