Two Caltech Professors Lead Missions About to Launch Back-to-Back into Space

This month will see two Caltech-led NASA missions lift off into space, one right after the other. NASA's Lunar Trailblazer is slated to launch from NASA's Kennedy Space Center in Florida no earlier than February 26, while NASA's SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) mission is slated to launch from Vandenberg Space Force Base in Central California no earlier than March 2.

Lunar Trailblazer will map water on the Moon, providing a better understanding of the lunar water cycle and identifying resources for future human missions. SPHEREx will look outward to the cosmos, studying the birth and evolution of the universe as well as the ingredients needed for life in our galaxy.

Both missions were selected as part of competitive NASA programs, in which a principal investigator, or PI, and their team propose detailed mission plans to NASA. Lunar Trailblazer's PI is Bethany Ehlmann, professor of planetary science, and Allen V. C. Davis and Lenabelle Davis Leadership Chair and director of the Keck Institute for Space Studies. The mission was selected for flight in 2019 as part of NASA's Small Innovative Missions for Planetary Exploration (SIMPLEx), which supports low-budget, higher-risk missions capable of major planetary science.

Lunar Trailblazer will hitch a ride to space with the Intuitive Machines' IM-2 lunar lander. Approximately 48 minutes after launch, the spacecraft will separate from the rocket and begin its monthslong flight to the Moon, which it will orbit for two years.

"Seeing an idea in CAD designs from over six years ago become actual hardware that will be launched into space to do the science is very gratifying," Ehlmann says. "It is thrilling to witness this payoff of years of hard work by the team."

SPHEREx is led by Jamie Bock, the Marvin L. Goldberger Professor of Physics at Caltech and senior research scientist at NASA's Jet Propulsion Laboratory (JPL), which is managed by Caltech. It was also selected for flight in 2019 but under NASA's Explorers Program as a Medium-Class Explorer (MIDEX). Bock and his team proposed the SPHEREx concept to NASA twice before it was ultimately selected, a process that resulted in nearly 3,000 pages of meticulously crafted scientific and technical information.

"Crunch time comes when finishing the reports," said Bock in a Caltech story about the SPHEREx proposal process. "That always comes down to the wire. We would meet every day and on weekends in what is referred to as the 'war room.' It would be filled with snacks, and we covered the walls with pages of the proposal. I quickly learned that it's impossible for a single person to oversee all the sections going into the proposal. You succeed or fail based on your team."

The main job of the PI is to ensure the mission is carried out so that it meets its science goals. This entails developing the basic concept and design of the instrument as well as the architecture of the team. It also means working closely with a day-to-day project manager to track progress and make decisions about risk and costs; in this case, both Ehlmann and Bock work closely with project managers at JPL.

In other words, a mission PI has a unique blend of skills in science, engineering, and leadership.

"Being a PI means setting the initial scientific objectives of the mission and team partnerships. Then it requires maintaining these over years and the challenges of hardware development," Ehlmann says. "It requires continual attention to make sure the design and engineering implementation choices and team organization will ultimately make the science happen—trading cost, risk, and capability."

Bock says his philosophy in leading a competed mission is to make the design as efficient as possible "so that the project design and team are focused on the purpose of doing their main job really well, while minimizing extra features. These choices set the trajectory of the project from the outset, where a good structure naturally leads to good execution."

Both missions were made possible by several partners around the globe. And both missions take advantage of the trifecta of Caltech, NASA's JPL, and IPAC, an astronomy center at Caltech—all located in Pasadena.

JPL manages both Lunar Trailblazer and SPHEREx for NASA, while IPAC plays a significant role in both. For Lunar Trailblazer, IPAC will serve as the operations hub, which differs from the typical arrangement in which a NASA center or aerospace partner fills the job. This takes advantage of IPAC's decades of experience operating instruments on space telescopes and processing the data.

Having the operations center on campus also means it is more accessible to undergraduate students: Both Caltech and Pasadena City College students work on Lunar Trailblazer.

"Being a PI at Caltech means you can infuse the mission work into the student experience," Ehlmann says.

In the case of SPHEREx, IPAC will both process the mission's data that stream in from space as well as serve as the main public data archive. "Caltech has been the perfect place for a mission of this scale due to the close connections between Caltech, JPL, and IPAC," Bock says. "What makes this partnership work is a 'badge-less environment,' where our relatively small team interacts closely on a daily basis without barriers. It is essential that many personal connections were already well established across the team before the project began. Caltech undergrads, graduate students, postdocs, and staff have had significant impacts in all phases of the project."

Caltech can boast about its faculty serving as PIs on other NASA missions as well. Chris Martin, the Edward C. Stone Professor of Physics and the director of Caltech Optical Observatories, served as the PI for NASA's GALEX (Galaxy Evolution Explorer), which operated from 2003 to 2013, while Fiona Harrison, the Harold A. Rosen Professor of Physics and the Kent and Joyce Kresa Leadership Chair of the Division of Physics, Mathematics and Astronomy, currently leads two NASA missions. She is the PI of NASA's NuSTAR (Nuclear Spectroscopic Telescope Array), which launched in 2012 and is still going strong, as well as of UVEX (Ultraviolet Explorer), which was recently selected for flight in 2024.

Incidentally, Caltech faculty have also served as project scientists for several NASA missions (such as NASA's Mars 2020 Perseverance rover, for which Ken Farley, the W. M. Keck Foundation Professor of Geochemistry, is the project scientist), but those missions are not competed for by PIs and are instead directed by NASA.

Launch-day coverage for both missions will be available on NASA's website and NASA+. Lunar Trailblazer launch coverage is anticipated to begin at approximately 3:30 p.m. Pacific Time on February 26. SPHEREx launch coverage is slated to begin at 6:15 p.m. Pacific Time on March 2, with the launch window opening at 7:09 p.m.

Additional Information About Lunar Trailblazer

In addition to management, JPL provides system engineering, mission assurance, the HVM3 instrument, and mission design and navigation. Lockheed Martin Space provides the spacecraft, integrates the flight system, and supports operations under contract with Caltech. The University of Oxford developed and provided the LTM instrument, funded by the United Kingdom Space Agency. Lunar Trailblazer, part of NASA's Lunar Discovery Exploration Program (LDEP), is managed by NASA's Planetary Missions Program Office (PMPO) at Marshall Space Flight Center in Huntsville, Alabama, for the agency's Science Mission Directorate (SMD) in Washington, D.C.

Additional Information about SPHEREx

BAE Systems (formerly Ball Aerospace) built the telescope and the spacecraft bus. The science analysis of the SPHEREx data will be conducted by a team of scientists located at 10 institutions in the US, two in South Korea, and one in Taiwan. The SPHEREx dataset will be publicly available at the NASA/IPAC Infrared Science Archive.