Capturing a tiny asteroid and nudging it into the Earth-Moon system for study by spacewalking astronauts is at the outer edge of U.S. capabilities right now, and will pull 's deep-space exploration technologies along even if it does not catch a space rock.
The idea has drawn a mixed reaction on Capitol Hill and elsewhere in the U.S. space establishment. Butmanagers consider it a unifying goal to bring focus to the various deep-space exploration development activities underway. In general, that work is going very well, considering NASA's mismatch of programs and money to pay for them.
The agency reports good progress on the heavy-lift Space Launch System (SLS) and Orion crew capsule that is central to its deep-space goals, including the asteroid mission. So far, NASA-oversight committees on Capitol Hill appear ready to keep money flowing to those two programs.
Meanwhile, astronomers already are looking for threatening near-Earth asteroids only a little larger than the one that would be captured, and International Space Station planners are preparing the life-science and engineering research necessary to keep an Orion crew alive on the 22-day asteroid mission. The long-duration solar-electric propulsion (SEP) technology necessary to reach and “redirect” the asteroid is on the horizon, and the capture mission could advance it enough to propel human crews down the invisible “gravity rivers” they are likely to follow deeper into the Solar System.
William Gerstenmaier, NASA's associate administrator for human exploration and operations, coined that term when NASA intensified its study of cislunar space as a jumping-off point for human exploration (AW&ST Oct. 15, 2012, p. 24). He has been briefing the asteroid-capture mission to Washington space stakeholders since it was presented in NASA's fiscal 2014 budget request April 10, stressing the effect it will have on capabilities over the scientific value of the asteroid itself.
“I believe there are other compelling aspects of this mission that are very worthwhile,” Gerstenmaier says. “To be able to understand the risk posture to take astronauts to this deep retrograde orbit; to understand the abort options out of those orbits; to look at the lunar gravity [factors], those are all tremendously important to us. I'm going to do those independent of whether we've got this asteroid or not.”
Astronomer Steve Squyres, the principal investigator on the twin Mars Exploration Rovers Spirit and Opportunity who chairs the NASA Advisory Council, finds that argument compelling, as well as the idea of broadening the study of near-Earth asteroids to include those in the 7-10-meter (22.9-32.8-ft.) class that conceivably could be captured. But in presenting his views to the National Academy of Sciences Committee on Human Spaceflight, Squyres said he believes it is too soon to say if the capture mission itself would be worthwhile.
“I don't know if this can be done,” Squyres says. “I don't know what it's going to cost. It's a very new idea; it's very immature.”
Administrator Charles Bolden met that same skepticism when he presented the asteroid-capture idea to the House Science Committee on April 24, and emphasized that the $105 million in NASA's fiscal 2014 budget request would only advance mission-concept and SEP technology work. While the House panel has held hearings on the threat to Earth from asteroids, its members also were unsure of the value in actually capturing one for study.
“I am concerned that NASA has neglected congressional funding priorities and been distracted by new and questionable missions that detract from our ultimate deep-space exploration goals,” said Rep. Steven Palazzo (R-Miss.), chairman of the panel's space subcommittee.”
In its “compromise” 2010 legislation authorizing NASA spending, Congress insisted the agency build the SLS and Orion as government-owned deep-space exploration vehicles, and as a backup to the planned commercial crew vehicles NASA is also helping to fund. Gerstenmaier says the first Orion flight article—an instrumented testbed designed to gauge just how thick and heavy the capsule's ablative thermal protection system must be to protect the crew on a high-velocity planetary return—is atawaiting arrival of the blunt-end heat shield from its manufacturer, and is on-track to fly on a Delta IV next year as planned.
SLS Program Manager Todd May says the main issues going into preliminary design review in June are whether the surplus space shuttle main engines can be operated safely—with enough performance—in the different loads environment they will see on the SLS main stage, and a casting problem that required a redo on one of the five segments of the solid-fuel booster qualification motor. The SLS remains on-track for a first flight in 2017, he says.
Bolden says the asteroid mission is the logical next step on the road to Mars, as long as Congress supplies the funds. “Since we're operating under a flat budget, the one that is executable in today's budget environment is an asteroid mission.”
But Sen. Barbara Mikulski (D-Md.) who chairs the Appropriations subcommittee that funds NASA, worries that the agency is not asking for enough funds to do the job, even without sequestration and other budget-trimming impediments.
“There's been a pattern, not only in NASA but across all agencies, to low-ball estimates,” she says. “Those low-ball estimates tend to be inaccurate, and then along comes something like sequester, which has a tremendous impact.”
Tap the icon in the digital edition of AW&ST for NASA's detailed mapping of the asteroid capture mission, or go to AviationWeek.com/asteroidcapture