WASHINGTON — Despite a desire by industry and policymakers for more details about NASA’s long-term plans to send humans to Mars, agency officials say they have no immediate plans to revise a Mars mission architecture last updated in 2009.
In presentations to a NASA Advisory Council committee Jan. 13 and the full council Jan. 14, NASA associate administrator for human exploration and operations William Gerstenmaier said the agency still had more to learn, including studies ongoing with academia, before it would be ready to update those earlier plans.
NASA last published a human Mars exploration plan, called a design reference architecture, in July 2009. The 100-page document, the fifth version of that study, outlines how the agency could carry out a human mission to the surface and Mars and back, including the launch vehicles and spacecraft required as well as other critical technologies needed for the mission.
“If you asked me how we would go to Mars today, I’d pull out design reference architecture number five,” he told the council Jan. 14.
However, the document is dated in some respects. Developed during the Constellation program, the architecture makes use of Ares 1 and Ares 5 launch vehicles that were canceled in 2010 with the rest of the program.
Gerstenmaier told the council that the Mars architecture could be updated with new technologies and techniques. He cited as one example the development of solar electric propulsion for more efficient transportation of cargo to Mars, a technology NASA is working on for its Asteroid Redirect Mission (ARM).
Another element of ARM that could affect Mars mission architectures is the use of a distant retrograde orbit around the moon, which has lower propulsion requirements to reach than alternative locations in the Earth-moon vicinity. “This distant retrograde orbit has excellent staging potential for Mars-class missions,” he said. “This orbit still needs more work, but it has lots of potential.”
Gerstenmaier said that discoveries about Mars itself could also alter mission planning. Since the 2009 publication of the latest architecture, a better understanding of the amount and distribution of water below the martian surface makes it more likely that it could be used by future human missions. “It’s tremendously important to us,” he said.
Despite these advances, though, he said it was still premature to update the 2009 architecture. “I don’t think I’m quite ready for that yet,” he told the council’s human exploration and operations committee. “We’re still really learning.”
Some of that learning is taking place outside of NASA. He cited as one example a study published last year by a group at the Massachusetts Institute of Technology (MIT) that examined Mars One, a private effort to establish a permanent human settlement on Mars as soon as 2025. The MIT study found that the Mars One habitat could reach unsafe conditions within months of landing, as crops grown there produce high levels of oxygen.
“That’s a very intriguing report,” Gerstenmaier said of the MIT study. “What it describes to us is how difficult sustaining humans on another world is really going to be.”
He said NASA is also advising a student design project at Purdue University looking at the use of “cycler” spacecraft, which would travel between the Earth and Mars, a concept developed by, among others, Apollo 11 astronaut Buzz Aldrin. “Their primary focus is to look at Buzz’s concepts, and to validate Buzz’s concepts, and we kind of tagged along,” he said, asking the student team to look at particular aspects of the cycler design.
Those and other studies will be incorporated into a broader ongoing effort within NASA called the Evolvable Mars Campaign to develop a strategy to support human Mars missions by the mid-2030s. That will help identify what Gerstenmaier called “big paybacks” in terms of technologies and designs that would have the most significant effect on future mission architectures.
More details about that strategy will be published this summer, he said. “It’s more of a plan for a plan,” he said of that effort. “It’s not a design reference mission per se.”