WASHINGTON — As NASA works on plans to fly humans on long-duration missions between the Earth and moon in the 2020s, the agency is also starting to think about what astronauts would do on those flights.
While NASA officials have talked for months about the possibility of developing cislunar habitats as an intermediate step in its plans for eventual human missions to the moon, the concept received an official endorsement in NASA’s “Journey to Mars” report published in October.
“NASA and its partners will also develop an initial habitation capability for short-duration missions in cislunar space during the early 2020s and evolve this capability for long-duration missions in the later 2020s,” the report states. “With this long-duration habitable volume and resources, NASA and its partners will have the opportunity to validate Mars habitat concepts and systems.”
Those long-duration missions could last as long as one year. “We’re going to use this one-year shakedown cruise in cislunar space to prove that all of our systems and crew health equipment, and our crews interacting with all of that equipment, can remain healthy, productive and relatively happy,” said Sam Scimemi, director of the International Space Station at NASA Headquarters, during a Nov. 5 meeting of the NASA Advisory Council’s human exploration and operations committee here.
While the primary purpose of those missions will be to test systems intended for later Mars missions, Scimemi said that the agency is looking at what other things astronauts in a cislunar habitat could do. “Once you have that capability to have humans in cislunar space for a year, or even for six months or two months, there are things that they can do and be productive at to meet other goals,” he said.
One of those things is something NASA already has on the books: the Asteroid Redirect Mission, where a crewed Orion spacecraft will dock with a boulder retrieved from a near Earth asteroid and moved into orbit around the moon. “Asteroid Redirect Mission fits into that perfectly,” he said.
Scimemi said NASA has had discussions internally, and with international partners, on potential additional missions that astronauts in a long-duration habitat could perform. Several of the ideas involve having astronauts teleoperate rovers and other spacecraft on the lunar surface, avoiding the time delays involved if they were controlled from the Earth.
“Some of the techniques and technologies to be able to do those things have already been demonstrated on ISS,” he said. “We’ve already controlled robots on the ground from the station.”
A cislunar habitat could be used to conduct other scientific research, or support research being performed by other spacecraft. In that latter category, Scimemi noted that a cislunar habitat could support astronaut crews tasked with assembling or repairing future large space telescopes based at Lagrange points. “Having humans in cislunar space could facilitate that,” he said.
Other work astronauts could do there include testing of other technologies needed for human Mars missions. One example Scimemi gave was long-term “zero boil off” technology for cryogenic propellant tanks, testing their ability to keep those propellants from boiling off on extended missions. That technology can be tested on the ISS, he said, but cislunar space provides a better environment than low Earth orbit.
NASA has also started studies of what the habitats themselves could look like. In March, it awarded contracts to Bigelow Aerospace, Boeing, and Orbital ATK to study concepts for cislunar habitats as part of NASA’s Next Space Technologies for Exploration Partnerships (NextSTEP) program. Lockheed Martin also received a NextSTEP contract to examine interfaces between such habitats and the Orion spacecraft.
“We have a requirement to build habitats that will initially be in cislunar space and are extensible to in-space transit habitats all the way to the Mars system,” said Jason Crusan, director of NASA’s Advanced Exploration Systems division, in a presentation to the committee Nov. 4. Those habitats could be based on commercial habitats for low Earth orbit missions, he said.
The NextSTEP contracts run for one year with a value of up to $1 million each. Three of the contracts are underway, Crusan said, with final negotiations with Boeing on its contract scheduled for completion in November.
Scimemi said that modules, provided by either companies or international partners, would be a much smaller challenge than the life support and related systems that would allow astronauts to live there for extended periods. “The module itself is the easy part. Multiple countries, multiple industry partners around the world can build modules,” he said. “It’s getting these systems to work that’s the hard part.”