WASHINGTON — House lawmakers preparing to write a new NASA authorization bill voiced doubts May 21 about the worthiness of sending astronauts to a relocated asteroid as soon as 2021 — the only mission, destination and timeline the U.S. space agency has identified for the heavy-lift launch vehicle and crew capsule it is spending nearly $3 billion a year to build.

The debate at the May 21 hearing of the House Science space subcommittee centered on whether asteroid retrieval and exploration are a necessary precursor for a crewed mission to Mars — something notionally on tap for the 2030s, according to goals the Obama administration set in 2010. 

Summing up the questions posed to a four-witness panel of space experts by most of the lawmakers at the hearing, Rep. Donna Edwards (D-Md.), the ranking member on the subcommittee, said that “many of us have had questions about … how that then contributes to going to Mars.”

Louis Friedman, the co-founder of the Planetary Society advocacy group and a key contributor to the study upon which NASA is basing the asteroid retrieval mission, said the most obvious benefit of sending astronauts to a small asteroid tugged to lunar space by a robotic retrieval craft would be to test the life support systems required to keep crews alive beyond Earth’s protective radiation belts. 

“I think that’s the dominant one,” said Friedman, co-leader of the Asteroid Retrieval Feasibility Study, which was published in April 2012 by the Keck Institute for Space Studies, part of the California Institute of Technology in Pasadena, Calif. 

Friedman also pointed out that NASA’s $16.5 billion budget — down about 7 percent from 2012 thanks to sequestration cuts — could not support human exploration missions to any other extraterrestrial bodies. Friedman also said the asteroid exploration campaign had superior public outreach value compared with the old Constellation Moon-return program the Obama administration canceled in 2010. 

“The joy of the asteroid retrieval mission is that we actually begin the process a couple of years from now,” Friedman said, noting that Constellation’s proposed Moon landing was slipping out toward 2030 at the time of the project’s cancellation. 

Cost estimates for the asteroid retrieval mission range from $1 billion to just over $2.5 billion. The Keck study assumed mission costs would ring in at the top end of that range. NASA officials, including Administrator Charles Bolden, think the agency’s final bill would be somewhere in the middle. Bolden says the Keck study did not take into account the work NASA has already done on the heavy-lift Space Launch System (SLS) and Orion crew capsule.

But the ability to test life support systems does not depend upon the presence of a target asteroid in lunar space, as another panelist pointed out as part of his argument to send SLS and Orion to near-Moon space even if there is nothing there to visit.

“Adopt cislunar space as the next milestone whether ongoing studies show it’s possible to redirect a small asteroid there or not,” said NASA Advisory Council Chairman Steven Squyres, an astronomy professor at Cornell University in Ithaca, N.Y. Squyres also implored lawmakers not to prescribe any milestones beyond an Orion cruise to cislunar space without also ensuring funds are available for such a mission.

“That would amount to an unfunded mandate, and that is the bane of government agencies,” Squyres said. 

Unwavering in his stance that visiting a captured asteroid was a waste of time for human explorers was Rep. Lamar Smith (R-Texas), who chairs the House Science, Space and Technology Committee and is keen to see astronauts return to the Moon. Smith lambasted the proposed asteroid retrieval mission as a “haphazardly” constructed project better carried out by robotically controlled probes.

“An astronaut could drill down into an asteroid, but a robot could do that too,” Smith said. “Is there any value to having an astronaut land on a 7- to 10-meter diameter asteroid?”

“I think we would learn something,” said Paul Spudis, senior staff scientist at the NASA-funded Lunar and Planetary Institute in Houston. “But in terms of what we’d learn [compared with] robotic sample return, I don’t think we’d learn much more.”

A former NASA official called to testify said he saw little connection between the asteroid retrieval mission NASA is now studying and human exploration of Mars. 

“This is a clever concept, and such a mission would undoubtedly demonstrate technology capabilities,” said Doug Cooke, a consultant who until 2011 was deeply involved with NASA human spaceflight as the agency’s associate administrator for exploration systems. “However, there is not a recognizable connection to a long-term strategy” for exploring Mars. 

Cooke also noted that since it is unlikely NASA will receive new funding for the robotic portion of the asteroid retrieval mission, the agency will have to get the money from existing programs. 

Meanwhile, the NASA authorization bill — a major policy document that will outline Congress’ priorities for the space agency — could arrive in a matter of weeks or months, lawmakers said during the hearing. 

A pair of House aides said May 21 that work on a new authorization act will probably begin in early June.

Dan Leone is the NASA reporter for SpaceNews, where he also covers other civilian-run U.S. government space programs and a growing number of entrepreneurial space companies. He joined SpaceNews in 2011.Dan earned a bachelor's degree in public communications...