From the hazards posed by deep-space radiation to the subtleties of spacesuit and closed-loop life-support system design, the U.S. faces significant technical and financial challenges if humans are to break out of low Earth orbit, according to witnesses testifying before a National Research Council (NRC) panel.
The obstacles will likely require NASA to seek closer ties with the Defense Department and international partners as well as the aerospace industry and academia; but these alliances may raise security concerns and prompt compromises on destinations and timescales, experts told the NRC’s Human Health and Surface Exploration Panel this week.
Yet the agency has little choice but to reach out in an era of fiscal constraint and long-running uncertainty over its future.
NASA’s dilemma was underscored in presentations by NASA’s Human Exploration Framework Team (HEFT), a group formed a year ago to provide the agency’s leadership with mission options for destinations stretching from the International Space Station to Mars. When it wrapped up work in December, HEFT was unable to define a politically sustainable course for any of the mission options, including President Barack Obama’s favorite, a near-Earth asteroid, by 2025. (See HEFT charts pp. 6-8.)
“We did not find an architectural solution,” Christopher Culbert, manager of NASA’s Exploration Missions & Systems Office, told the NRC panel. “We do not believe it’s possible to satisfy all of the stakeholders. Somebody walks away unhappy.”
Partnerships
HEFT activities have since transitioned to the Human Spaceflight Architecture Team, or HAT, a sustained in-house NASA effort that is looking for technical collaborations with the Defense Advanced Research Projects Agency as well as the International Space Exploration Coordinating Group, which is hosting a June meeting in Tokyo to discuss destinations, dates and technology challenges.
Assessments to date suggest that investments in a heavy-lift rocket and a multipurpose crew vehicle — programs funded in the recently enacted 2011 budget continuing resolution — offer the greatest leverage in addressing technical hurdles to deep-space missions, says NASA’s Scott Vangen, who leads the HAT technology assessment team.
Additional spending on advanced propulsion technologies that could hasten the transit to Mars from months to weeks appear justified as well because they lower exposures to the little-understood effects of galactic cosmic radiation and ease the requirements for closed-loop life-support systems, Vangen says.
Other experts stressed the need for strides in modeling human radiation exposures, advanced dosimetry and spacecraft shielding.
While NASA has made progress in recycling water and breathing air aboard the International Space Station, engineers are finding the life-support hardware less reliable than hoped. The difficulties have been tempered by shuttling temperamental components to the ground for troubleshooting and an aggressive resupply strategy, approaches that won’t be possible on deep-space missions.
The current U.S. spacesuit was introduced in 1982 for use by shuttle crews. The equipment has been adapted for the space station, and engineers have devised strategies for in-space rather than ground-based refurbishments.
But current space garb lacks the mobility and dust filtering for use on planetary surfaces. The shuttle suits are uncomfortable and not sized to accommodate a wide range of body types.
The nine-member Human Health and Surface Exploration Panel is one of a half-dozen NRC sub-groups assembled to assess 14 NASA draft Space Technology Area Roadmaps and shape priorities. A research council steering committee plans an interim report in August and a final document in January.
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