Thomas Zurbuchen Retires as Head of NASA’s Science Directorate

Dr. Thomas Zurbuchen stepped down as the Associate Administrator of NASA’s Science Mission Directorate at the end of 2022. Sandra Connelly is currently filling in as Acting Associate Administrator.

The Science Mission Directorate oversees scientific missions in planetary science and astrophysics. It also oversees NASA’s earth science projects.

Dr. Zurbuchen took the job of Associate Administrator in 2016. During his tenure, he oversaw major accomplishments like the launch of the James Webb Telescope, the landing of the Perseverance rover and accompanying Ingenuity helicopter drone on Mars, and the successful execution of the DART mission, which slammed a small spacecraft into an asteroid to change its trajectory.

Not that it was always easy. The James Webb Telescope saw several frustrating delays in its launch, finally giving NASA a nice Christmas present with a successful launch on December 25, 2021. Zurbuchen admitted that there were moments when he considered canceling it.

He told New York Times that he was “basically asking the question, ‘Is it worth finishing?’ Not knowing what the answer was and going through the process was really, really hard.”

Seeing the first pictures from the James Webb Space Telescope before they were released to the public was a nice reward for his patience. However, not all missions got the same consideration during Zurbuchen’s tenure. He axed the Radiation Budget Instrument, which would have measured sunlight reflecting from Earth, within months of taking office as Associate Administrator due to technical issues and spiraling costs.

Now NASA buys most of its earth science data from other owners of Earth observation satellites, following a relatively new policy of leasing services from outside parties rather than buying hardware from contractors. The Commercial Crew Program, which allows NASA to buy rides on privately owned spacecraft like the SpaceX Crew Dragon rather than build and maintain its own fleet, is one example of this policy.

Of course, the policy of buying services from outside owners of space hardware typically relies on outside parties making at least some of the investment. A plan to use geostationary satellites for communication fell through because telecommunications companies were starting to move away from building geostationary satellites. (Blame SpaceX if you want. It was spearheading the idea of having thousands of Internet-providing satellites in low-Earth orbit, where it could get better latency.)

“We basically lost our rides,” Zurbuchen said. However, that didn’t discourage him from seeking cost-effective ways to do things. “What I really felt was important is that we looked at the opportunity set and basically asked, ‘Is there a way to get more science or more science per dollar?’” he explained.

One way to do that: CubeSats. These small yet capable satellites could be launched as a secondary payload on rockets launching bigger scientific instruments and equipment tests like the recently successful test flight of an uncrewed Orion spacecraft. Secondary payloads on Artemis 1, which launched the Orion spacecraft, included ten CubeSats with a wide variety of scientific missions. One of those CubeSats was BioSentinel, a mission to study the effects of radiation on microorganisms in the vicinity of the Moon.

The International Space Station helped with the BioSentinel experiment by hosting a control sample. Scientists already have a pretty good understanding of the radiation environment in its orbit from the many past biomedical experiments that have been conducted on the orbiting laboratory. The International Space Station’s altitude averages about 350 kilometers.

With Dr. Zurbuchen’s departure from the Science Mission Directorate, Sandra Connelly became the Acting Assistant Administrator for the Directorate. Connelly has more than 30 years of experience in portfolio, program and project management, including previous leadership roles at the Science Mission Directorate and NASA’s Office of the Chief Engineer.