NASA officials this morning said the agency is not retreating from human space flight. The agency was responding to critics who contended that President Barack Obama's proposed 2011 budget, released yesterday, would end all such programs and thus result in a serious decline in the US space program.

The space agency had announced yesterday that Obama's plan would scrap NASA's latest plan to return humans to the moon by 2020. The budget instead aims to turn NASA's immediate attention to developing new engines, in-space fuel depots and robots that can venture out into space, paving the way for future missions that would return humans to the lunar surface.

"The future is unfolding before us now and its exciting," said NASA administrator Charles Bolden. "We're not abandoning anything. We're probably on a new course, but human space flight is in our DNA. We are not abandoning human space flight by any stretch of the imagination. We have companies telling us they're excited to get humans off this planet and into orbit. I think we're going to get there and perhaps quicker than we would have done before."

The Obama administration plan does call for cancelling the Constellation moon landing plan that was hatched in 2005 by the administration of former President Bush.

Bolden said he supports the new Obama administration budget plan, which calls for NASA to hire private companies to build space taxis that would shuttle astronauts to the International Space Station. The old Constellation plan, which already has cost $9 billion, was behind schedule, and was projected to ultimately be over budget.

"I am convinced this approach is the right approach for this time, these challenges and these opportunities," said Bolden during a speech at the National Press Club. "It is not a retreat for human space flight but an investment in new ideas and new technologies. We're excited to have new direction from president."

Bolden also publicly thanked the people who worked for several years on the Constellation project.

"They are not hobby shoppers as some in the media have called them. They are dedicated people with dreams of bold exploration," he added. "To people who have worked on the Constellation program, this is like a death in the family. We need to give them time to grieve and then give them time to recover. This is part of the life of being in NASA. Every time we manage to pull through it and we manage to recover and we go on to do great things."