Cassini Enceladus
An illustration of NASA's Cassini spacecraft flying through a plume above the surface of Saturn's moon Enceladus. Credit: NASA/JPL-Caltech

LUXEMBOURG CITY — The Breakthrough Prize Foundation, the organization funded by Russian billionaire Yuri Milner, is examining the feasibility of a private mission to a moon of Saturn.

The effort, still in its early study phases, could eventually lead to a mission to the moon Enceladus. That icy moon likely has an ocean of liquid water underneath its surface, based in part on plumes emanating from its surface as seen by NASA’s Cassini mission. That has raised its prospects as a potentially habitable world.

Milner first revealed his foundation was considering such a mission during an on-stage interview at a conference in Seattle Nov. 9 organized by The Economist magazine. “We formed a little workshop around this idea,” he said. “Can we design a low-cost privately-funded mission to Enceladus, which can be launched relatively soon and that can look more thoroughly at those plumes to try to see what’s going on there?”

Such a mission, he said, would be a precursor to a possible future NASA mission that would be more sophisticated, but also more expensive and take longer to develop. Enceladus is one of the potential destinations for the next New Frontiers medium-class planetary science mission, the competition for which is ongoing.

Milner said that all options were being considered, from a simply flyby of Enceladus to a spacecraft that might enter orbit around Saturn and make multiple flybys of the moon. “How can we, for the first time ever, design and send, and launch actually, a privately-funded interplanetary science mission?” He did not disclose additional details about the concept at that event.

Pete Worden, the former director of NASA’s Ames Research Center who is now chairman of Milner’s Breakthrough Prize Foundation, mentioned the study effort during a Nov. 16 talk at the NewSpace Europe conference here.

“We did an initial study,” he said. “We met with our sponsor, Mr. Milner, in August and said we could probably do it, using more conventional means, for a few hundred million dollars.”

Milner, Worden recalled, considered that too expensive. “So he sent us back to look at interesting lower-cost efforts, and we found a few,” he said. He didn’t discuss those alternatives in detail, but suggested some involved solar sails or “light sails” of some kind.

“We’ll probably kick off, around the first of the year, a six-month study to look at some of these” alternative mission concepts, he said. “Hopefully, later this next year, if it looks good, we’ll be off and running.”

He added that mission, if approved and funded by Milner, could be done in cooperation with space agencies, adding that both NASA and the European Space Agency had been briefed on the concept.

NASA is currently evaluating the dozen proposals submitted in April for what would be the fourth New Frontiers mission. At least two of the proposed missions would go to Enceladus. Jim Green, director of NASA’s planetary science division, said at a Nov. 14 meeting of the Venus Exploration and Analysis Group that the evaluation was “proceeding very nicely” with plans to select three or so proposals by the end of the year for additional study. NASA would make a final selection in the spring of 2019 for launch by 2025.

It wasn’t clear, based on Milner’s and Worden’s comments, whether a NASA selection of an Enceladus mission would be a prerequisite for going ahead with a privately-funded mission intended as a precursor.

The Enceladus mission studies are the latest project by the Breakthrough Prize Foundation. In addition to its namesake prizes in fundamental physics, life sciences and mathematics, the foundation has backed several initiatives focused more on the search for life beyond the solar system.

Breakthrough Listen, announced in 2015, will spend $100 million over 10 years to fund projects associated with the search for extraterrestrial intelligence (SETI), such as paying for telescope time at several radio observatories. Breakthrough Starshot, announced in 2016, is another $100 million, 10-year effort, this time to study technologies that could be used for laser-propelled light sails that could send chip-sized spacecraft to nearby star systems.

Milner, who became wealthy through investments in technology companies, including Facebook and Twitter, has faced more scrutiny about those investments recently. An investigation by the New York Times published earlier this month found that some of the funds he received to invest in those and other companies came from firms with ties to the Russian government.

Milner, asked about this at the Seattle event, noted the Russian funding came in 2009, when relations between the United States and Russia were in better condition, and that he returned the funds in 2014. He added he has tried to stay out of politics throughout his life. “People who know me well,” he said, “know that my real passion is technology, science and space.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...