Director's Log, Chandra Date: 703296006

Belinda Wilkes,

The past year has been a busy and exciting one for the Chandra Project.

Three key milestones were successfully met:

  1. NASA’s SR2019 senior review, which ended up on a later than planned schedule due to the long government shut-down at the start of the year, went very well. Chandra scored an "Excellent" rating, with favorable comments and a recommendation for an augmented budget to address labor inflation and increase General Observer funding, which NASA HQ has since enacted. Other advice included enhancing the Chandra Cool Target (CCT) initiative in future cycles, optimizing Chandra’s preparations for the anticipated increase in transient-optimized surveys over the next few years, and recommendations to ensure the long lifetime and usefulness of the Chandra archive and software following decommissioning.
  2. The planned construction and move to a new Operations Control Center (OCC), initiated in June 2017 by the lack of renewal of the lease for the Cambridge OCC, was successfully completed in May, ahead of the expected schedule. There were no major problems as we switched command from the old Kendall Square OCC to the new "Wayside OCC" in Burlington, MA. After 2 years of hard work by many, the operations staff are now happily settled into their beautiful, new, state-of-the-art facility, designed with a detailed knowledge of what it takes to operate Chandra in all circumstances1. The new layout and expanded common spaces also provide enhanced opportunities to hold meetings, events, and tours. A celebratory reception was held in the Wayside building cafeteria on 23 July, the 20th anniversary of Chandra's launch, to celebrate both the day and our new facility. The event included the opportunity to tour the new OCC, and to hear and visit with Astronaut Dr. Cady Coleman, the Chandra Mission Specialist on the shuttle Columbia.
  3. The 2nd major release of the Chandra Source Catalog, CSC2, was finalized and made public in October 2019. While targets were made available throughout the previous year as processing proceeded, the final release froze the results and generated multiple products for use by the community and the public. CSC2 includes measured properties for 317,167 unique, compact and extended X-ray sources, allowing statistical analysis of large samples, as well as individual source studies. Extracted properties are provided for 928,280 individual observation detections identified in 10,382 Chandra ACIS and HRC-I imaging observations released publicly through the end of 2014. Details can be found on the CXC website.

Our 20-year anniversary celebrations filled the year 2019, opening with a large AAS Exhibit in January and culminating with the highly successful 20 years of Chandra Science conference in Boston. Special sessions, invited talks, and exhibits were held at multiple conferences, including the HEAD meeting in Monterey, the APS April meeting in Denver (a new one for us), the summer AAS in June in St. Louis, and the X-ray Astronomy meeting in September in Bologna, Italy. We held a highly successful reception at Smithsonian’s NASM on 26th August, celebrating the 20th anniversary of Chandra’s first light image release. It was attended by Smithsonian Institution, NASA, industry partners, and astronomy VIPs, astronaut Cady Coleman, and CXC and MSFC Chandra managers and senior staff. The event included speeches and science talks to accompany the renewal of old friendships and general celebrations. Throughout the year, we organized both colloquium series and astronomy-on-tap series throughout the US and internationally, providing speakers as needed. Many public talks and events were held, some in conjunction with science talks, throughout the US. Several events involved "our" Columbia crew astronauts: Commander Eileen Collins, Mission Engineer Steve Hawley, and Chandra Mission Specialist Cady Coleman.

20 year celebratory "swag" covered a wide variety of products and media, special press releases, a movie, new 3-D virtual reality (VR) products and 3-D prints, special displays, and much more. A beautiful "coffee table" book: Light from the Void, filled with beautiful Chandra images, some combined with data from other great observatories and large telescopes, was published by Smithsonian Books, to great acclaim by the public and the community alike, and in good time for Christmas. It can be purchased on Amazon or Smithsonian Books.

The year ended with the major science event: the 20 years of Chandra Science conference, held in the Boston Park Plaza Hotel, 3-6 December. As well as the excellent review talks, science talks, general poster sessions, demonstrations and exhibits, the program included a special session dedicated to Nobel Prize Winner Dr. Riccardo Giacconi, the "father of X-ray astronomy", who died in late 2018, an excellent and fitting tribute, and a special session with 3 of "our" astronauts (Collins, Coleman and Hawley2). The astronauts treated us to a video of the launch which had not been shared publicly in the past. It included the ground control room voice recording, with details of the multiple problems encountered during launch. We were left on the edges of our seats, amazed that Chandra made it into orbit at all, and even more grateful to the shuttle crew and all the ground support personnel who made it happen against all odds. We are now even more thankful that we are here, 20 years later, celebrating Chandra’s scientific accomplishments to date. The conference was a fitting end to a wonderful year of celebration, as well as a tribute to the hopes and dreams, the years of work, and the expertise and dedication of the extended Chandra community, without which Chandra would not be the huge success that it continues to be.

The final "icing on the cake" was the publication of an electronic-book (ebook): The Chandra X-ray Observatory: Exploring the High Energy Universe, by IoP as part of their series in collaboration with the AAS. The book was edited by Belinda Wilkes and Wallace Tucker and includes in-depth reviews of Chandra and its science, with each chapter authored by experts in their field. It was prepared and written for the scientific community, providing a summary of how Chandra began, and its science and impact over the past 20 years. The ebook takes advantage of this medium to include movies and interactive multi-wavelength and 3-D figures, as well as live links to supporting material, referenced papers etc.. The ebook and hardcopies are available from the IoP website. Most astronomy libraries have a subscription to this series, providing access to the ebook to their members.

Despite all this additional and exciting activity, Chandra’s normal operations continued unabated. The observing efficiency has remained at its maximum, 70% of wall-clock time, and proposals, papers, press releases have continued as usual. Chandra Cool Targets (CCTs) are being observed at an average rate of ~5 per month, as needed to maintain the thermal balance of the spacecraft’s subsystems and ensure an efficient schedule.

The Cycle 22 Call for Proposals was released on 17th December 2019. Given the increase in complexity of mission planning, we have developed a new method to track the level of difficulty of scheduling each observation. The ability to determine the "Resource Cost" (RC) of an observation or program was made available in mid-February 2020. The RC combines all previously limited parameters, e.g. constraints, ecliptic latitude, into a single number, with the exception of Targets of Opportunity, which will continue to be accounted for as they have in the past. As previously for constraint categories, each panel will be given an allocation of RCs and ToOs (of each type) determined based on the request in that panel.

Since we know many of you continue to be adversely affected by the worldwide lock-down due to the COVID-19 epidemic, the Cycle 22 proposal deadline was moved from 17th March to 2nd April to provide some additional time as transitions to remote work and teaching occurred throughout the worldwide community. We are also considering a supplementary call later in the year and will be contacting the community to gauge the demand. As I write, the delayed Cycle 22 proposal deadline has passed and proposal numbers appear very consistent with last year, which is a reassuring and welcome surprise! Given our need for targets in advance of the next cycle, we cannot delay any further. The peer review is scheduled to begin on 15 June, as planned, but with all reviewers participating remotely. This promises to be an adventure, and I suspect that some of the development required for a remote review will enhance our in-person reviews in future years. While we hope that CXC staff can be in place at SAO to coordinate these panels, we are also preparing for the possibility of a fully remote review should circumstances require it. We do hope that many of you will be able to (tele-)join us from your homes or offices to help ensure that Chandra’s science remains of the highest quality in Cycle 22 and beyond.

No science workshop was held in the summer of 2019 due to the 20 years science symposium a few months later. Plans for the 2020 workshop are underway, although the COVID-19 pandemic may result in a change of schedule from the current plan of 4-6 August. The topic: "Chandra Frontiers in Time-domain Science", is timely as the astronomical community prepares to respond to increasing results from facilities optimized to find transients (e.g. ZTF, ASSASN, MAXI), to continuing gravitational wave triggers (LIGO/Virgo), and looks forward to the start of operations of the Vera C. Rubin Observatory in the near future.

As the COVID-19 pandemic holds the world in its vice-like grip, the observatory transitioned to telework as far as possible starting in mid-March. Chandra satellite operations continue as usual, but require a skeleton staff to be present onsite for DSN contacts. The shifts are being carefully planned to ensure minimal/no personnel overlap, including the use of different equipment and locations, and gaps between shifts. We also have a permission system in place for occasional on-site presence by other personnel, such as those who support the computers and other ground systems, and those who would need to be on-site should a spacecraft anomaly occur. Chandra is safest when it is observing, particularly given the decay of the thermal insulation which results in significant heating if it stares at one sky position for too long. To ensure its protection, we are developing command sequences which will keep it as safe as possible for a fairly extended period in case this should be required.

I would like to send my best wishes to all members of our extended Chandra community as our whole world fights to combat the COVID-19 pandemic and minimize the resulting suffering and loss of life. I hope that you and your families remain healthy and will continue to be so. Most of us have not experienced any event of this scale during our lifetimes, although certainly there are many who have given the multiple wars, mass migrations, and natural disasters that have occurred over the past decades, and continue today. While it is hard to find a silver lining, I hope that we will all learn and grow, both in ourselves and from one another, as we explore and adjust to new ways of living and working, and that our experiences will help us be more empathetic and understanding towards those who may suffer similar, major life upheavals in the future.