Foust Forward | Balancing big and small in space science

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“Foust Forward” appears in every issue of SpaceNews magazine. This column ran in the Aug. 13, 2018 issue.

“Know your audience” is one of the first rules of public speaking, and Thomas Zurbuchen, NASA associate administrator for science, made sure he followed it.

“This is the first talk in a month that I don’t have to talk about James Webb,” he said in the opening of his keynote Aug. 6 at the AIAA/Utah State University Conference on Small Satellites. The audience laughed and applauded. “I like James Webb, but I’m still glad I don’t have to talk about it today.”

The more than 3,000 conference attendees had little professional interest in NASA’s giant space telescope with its giant, and growing, price tag. Instead, they were interested in how NASA would make greater use of smallsats to achieve its science goals.

It would be difficult to find a bigger advocate for science smallsats within NASA than Zurbuchen. A few years ago, he chaired a National Academies committee that examined the scientific utility of cubesats, concluding that they could carry out a wide range of science missions. He discussed the results of that study at the same conference in 2016, less than two months before he joined NASA.

At NASA, he’s been able to implement some of the recommendations of that report by bolstering the agency’s use of smallsats for science missions. At this year’s conference, Zurbuchen announced the Science Mission Directorate would spent $100 million a year on cubesat and other smallsat programs, from data purchases to technology demonstration missions.

Smallsats aren’t new at NASA, of course, but the adoption of cubesats in particular has been uneven across the agency. Earth science and heliophysics have made the most use of them, largely because the science they want to do can fit into the mass, volume and power limitations of cubesats, and can also be done from Earth orbit.

Michael Seablom, chief technologist of NASA’s Science Mission Directorate, said in a conference presentation Aug. 7 that the agency estimated 40 percent of its Earth science measure requirements, outlined by the decadal survey, could be carried out by smallsats. In heliophysics, “nearly all” the measurements for its major decadal survey missions could be done by smallsats. (He said later that the scientific community “is not in 100 percent agreement on the finding,” but that nonetheless there were still many opportunities for heliophysics smallsats.)

Planetary science and astronomy, though, have been laggards. Planetary science missions to other worlds in the solar system impose major technical challenges for cubesats. Astronomy missions have been reticent to use cubesats because they desire large apertures to collect as much light as possible. “Astrophysics is signal-starved,” said David Ardila of the Jet Propulsion Laboratory during an Aug. 4 talk at a pre-conference workshop.

That’s changing, though. Ardila is working on a cubesat that would measure variations in ultraviolet light around low-mass stars that could make them unlikely to host habitable exoplanets. Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA), an experimental cubesat launched from the space station in November, won the small satellite mission of the year award in a vote held during the conference.

NASA’s first deep space cubesats, the two Mars Cube One (MarCO) cubesats, are now halfway to Mars and working well, Anne Marinan of JPL said in a workshop talk Aug. 5. Those satellites will relay data from the InSight Mars Lander during its landing, and may have an extended mission after that to collect more engineering data.

By the end of the conference, Zurbuchen was across the country at the Kennedy Space Center for final pre-launch preparations of Parker Solar Probe, a mission near the opposite end of the cost spectrum as cubesats. Big missions, in terms of size and cost, will remain a part of NASA’s science portfolio for the indefinite future, but there’s more room at the other end for small but increasingly capable missions.


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Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. His Foust Forward column appears in every issue of the magazine.