WASHINGTON — One of the aerospace industry’s most widely respected experts told House lawmakers March 24 that NASA’s proposal to rely on commercial crew taxis for operations in low Earth orbit is too risky and urged Congress not to approve the plan.

During a hearing before the House Science and Technology space and aeronautics subcommittee, former Martin Marietta Chief Executive A. Thomas Young said NASA should continue the Moon-bound Constellation program President Barack Obama proposed canceling in his 2011 budget request. Young said the Obama plan would leave the nation reliant on a private sector that is “a long way” from satisfying human space transportation needs.

“This is a risk too high and not a responsible course,” said Young, a venerable industry veteran who is frequently called upon by the government to assess civil and military space programs. “The commercial crew option should not be approved.”

Young’s comments stood in contrast to the findings of an expert panel tasked with assessing Constellation’s goals and hardware, including the Orion crew capsule and Ares 1 launcher, and potential alternatives. The panel, led by former Lockheed Martin chief Norm Augustine, said outsourcing astronaut transport to and from low Earth orbit is feasible, and could free NASA to pursue manned exploration deeper into space.

Testifying alongside Doug Cooke, NASA’s exploration systems mission chief, Young said companies like Hawthorne, Calif.-based Space Exploration Technologies Corp. and Dulles, Va.-based Orbital Sciences Corp. should be “encouraged, supported and applauded” for their accomplishments to date. The two companies are developing new rockets and capsules to conduct logistics missions to the international space station and are under contract to each deliver each 20 metric tons of cargo to the orbital outpost beginning in 2011.

However, Young said the commercial cargo services have yet to be proven, and that it would be a mistake to turn over crew operations in low Earth orbit to private industry.

Most of the subcommittee members in attendance were skeptical of Obama’s plan, though at least one, Rep. Dana Rohrabacher (R-Calif.), said he supports handing crew transportation to the private sector.

“If the private sector can do something for half as much, or even one-fifth as much, as what the public sector can do, we are limiting what our accomplishments are going to be in space by insisting that the government and the bureaucracy is the only one who can really be trusted to get the job done,” he said.

Young said the U.S. Air Force tried something similar in the 1990s, ceding top-level management of national security space programs to industry under a contracting approach called Total System Performance Responsibility (TSPR).

“Air Force and [National Reconnaissance Office] project managers were told to step back, to not interfere and to let industry have total responsibility,” he said. “The results were devastating, and the adverse impact is still with us today.”

Rohrabacher asserted NASA’s more than $9 billion investment in Constellation has yielded “not one new piece of technology.”

But Cooke said NASA has developed about a dozen new technologies under the program, many of which are part of the Orion crew capsule, “that will be potentially migrated into our technology programs.”

Young said NASA’s significant investment in Orion and Ares 1 should not be abandoned. “Constellation should not be canceled,” he said.