This story was updated at 7:47 p.m. ET.
COLORADO SPRINGS, Colo. ? Change may be difficult for NASA but it is vital for the space agency's future, NASA chief Charles Bolden told an audience of space industry experts and representatives Tuesday.
Bolden's talk, delivered to government, military and private industry space workers here at the 26th National Space Symposium, comes just two days ahead of a major space policy speech President Barack Obama is preparing to deliver Thursday in Florida. Both leaders are facing the tough job of defending their new vision for NASA to a sometimes skeptical public and Congress.
The Obama administration outlined the new plan for the United States' space agency in its 2011 budget proposal released in February. That vision calls for an increased focus on technology development aimed toward possible missions to the moon, asteroids or Mars.
It also replaces NASA's current Constellation program to go back to the moon and beyond, which Bolden called "unsustainable."
"Some of the controversy about what were about to do ? I think a lot of it comes from people who are nervous about doing new things," Bolden said. "I would say, as we are about to do something that a lot of people don't think we can do, take a deep breath and help us figure out a way to make these things work. Because I'm convinced we can do it."
A point of contention over the new plan has been the cancellation of Constellation's Ares rockets and the Orion crew module planned to fly atop them. These spacecraft were designed to replace the space shuttle, which is due to be retired later this year. Just four more shuttle flights remain, one of which is under way right now aboard the shuttle Discovery.
Instead of developing those new spaceships, President Obama proposes that NASA encourage private companies to development a transportation system to take astronauts to low-Earth orbit and the International Space Station.
"Government has blazed the path to low-Earth orbit in the past," Bolden said. "New players are now ready to engage that field."
But not everyone agrees that the commercial space industry is ready.
?I think we want it to succeed so much that we will miss the inherent risks that are in that approach,? said Scott Pace, director of the space policy institute at George Washington University in Washington, D.C., during a separate Tuesday panel at the National Space Symposium.
Some critics have charged that leaving the work of transporting astronauts to low-Earth orbit to commercial players would end America?s dominance in space, or lead the nation on a path toward giving up its human spaceflight program altogether.
In response to that accusation, deputy NASA administrator Lori Garver said, at the same panel, ?Wow. This program does the opposite. In fact it was the other program that was doing that.? She said the Constellation program actually would have eroded America?s human spaceflight abilities because it was such an unsustainable path.
If NASA did cede this duty to private companies, that would free up the agency to work on new space technologies to travel farther out into the cosmos.
?We need to reinvest in cutting-edge technologies,? Garver said. ?We want to expand the boundaries of human space exploration beyond our home planet.?
Bolden mentioned inflatable space habitats, novel space propulsion mechanisms, and next-generation heavy-lift rockets as a few of the avenues for research. He has said repeatedly in the past that NASA will not abandon the work performed under the Constellation program.
The agency will carry over know-how and research to the new plan as it applies, Bolden has said.
"The fundamental goal has not changed ? to boldly advance human presence beyond the cradle of Earth," he added Tuesday.
Committed to spaceflight
Bolden reaffirmed President Obama's support for NASA and for the future of space exploration. In an era of extreme budget pressure, he said, the president has decided to increase NASA's budget.
"President Barack Obama is strongly committed to our future in space," Bolden said. "We are so committed that we made the hard choice to undertake a new direction... to find a more affordable and sustainable path."Between the space symposium underway here, and Obama's speech on Thursday, Bolden said it's an important time for the space industry.
"This is a big week for the entire nation," he said. "A week in which probably more people than ever before will be thinking about space."
Another important element of the new plan for space is the emphasis on education and outreach to youth, Bolden said.
"I can't emphasize enough how passionately President Obama and I feel about educating and inspiring the next generation," he said.
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