NASA Administrator Sean O’Keefe told U.S. lawmakers worried about the Hubble Space Telescope’s future that robotic servicing of the orbiting observatory appears to be more feasible than agency officials initially believed.

“It’s looking a lot more promising than I would have told you a few weeks back,” O’Keefe told members of the House Appropriations VA-HUD subcommittee during an April 21 hearing on NASA’s 2005 budget request.

O’Keefe said what changed his mind was the quality of some of 26 responses the agency received in response to a recent call for ideas for servicing the Hubble Space Telescope (HST) without putting a space shuttle crew at risk.

“Some of the ideas we’ve heard are using capabilities that exist right now — actual hardware exists right now,” O’Keefe said, adding, “It looks feasible at this juncture ... I’d have to put more stock in it right now.”

Ed Weiler, NASA’s space science chief, told reporters in February that extensive robotic servicing did not appear feasible given the current state of technology.

O’Keefe said NASA is now taking a closer look at two or three robotic options for extending Hubble’s service life and possibly even outfitting the telescope with one or more new instruments. NASA engineers will pick the most promising robotic option by June, he said, and then spend the rest of the summer examining it in greater detail.

O’Keefe said that while it is not yet clear that robotic servicing will pan out, his intent is that NASA be ready by September or October to move ahead with implementation of such a mission if it still appears feasible after enduring greater scrutiny.

Among the robotic servicing technologies presented to NASA are Johnson Space Center’s Robonaut and the University of Maryland’s Space Systems Laboratory’s Ranger robot.

Robonaut is a human-like android designed by the Robot Systems Technology Branch at Johnson in a collaborative effort with the Defense Advanced Research Projects Agency. The Robonaut project is focused on developing and demonstrating a robotic system that can perform the same duties as a spacewalking astronaut.

The University of Maryland’s Ranger robot is flight ready, according to its designers, and has dexterous manipulators capable of working on Hubble. The Ranger robot has already undergone testing against Hubble servicing tasks, according to project personnel.

O’Keefe would not say whether these robots had made NASA’s short list of promising approaches.

Scientists and engineers expect Hubble to fail in 2007 or 2008 unless its gyroscopes and aging batteries are replaced. NASA announced Jan. 16 that it was canceling a final planned space shuttle mission to repair and upgrade Hubble, saying the mission was too risky in light of the Space Shuttle Columbia disaster.

Public and congressional outcry prompted NASA to solicit alternatives to a space shuttle mission for servicing Hubble.

The National Academy of Sciences, at the urging of Congress, is also reviewing the safety assumptions that went into NASA’s decision to scrap the shuttle servicing mission. That report is due in September.

The academy panel includes scientists, former astronauts, NASA managers, aerospace industry executives, a member of the Columbia Accident Investigation Board, and a robotics expert.

The study,  “Assessment of Options for Extending the Life of the Hubble Space Telescope,” is to be completed under the auspices of the academy’s National Research Council and its Space Studies Board and Aeronautics and Space Engineering Board.

Louis Lanzerotti was  selected to chair the study group. He currently consults for Bell Laboratories, Lucent Technologies and is a distinguished professor for solar-terrestrial research at the New Jersey Institute of Technology.

The study group will consider issues of safety in using the space shuttle for HST servicing with an astronaut crew; examine the feasibility of robotic servicing approaches; assess the impacts of servicing options on the HST’s scientific capability and judge the risks and benefits of the servicing options deemed acceptable.

The group will also estimate the time and resources that will be needed to overcome any unique technical or safety issues to ensure they conform to the recommendations of the Columbia Accident Investigation Board and NASA’s Stafford-Covey Return-to-Flight committee.

In addition, the panel is to assess how the HST might be affected by component failures and whether a failure would have an impact on the feasibility of a servicing mission. They also have been asked to study how component failures would affect Hubble’s scientific productivity and NASA’s ability to safely dispose of Hubble at the end of its service life.