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Obama's proposal to cancel the Constellation program and call on commercial spacecraft builders to provide the spaceships to launch astronauts into space has drawn harsh criticism from lawmakers and the public alike.
Most recently, famed Apollo 11 astronaut Neil Armstrong -- the first person to walk on the moon -- and other lunar explorers spoke out against the plan in an e-mail statement sent to the media. Armstrong and fellow Apollo program astronauts Jim Lovell and Eugene Cernan called Obama's space vision "devastating" to the United States' spaceflight legacy.
"To be without carriage to low Earth orbit and with no human exploration capability to go beyond Earth orbit for an indeterminate time into the future, destines our nation to become one of second- or even third-rate stature," the former astronauts wrote.
Obama's new plan also has supporters.
"Space exploration involves more than human. The robotic exploration of space is doing very well, and is enhanced in the President's plans for NASA. The new human space flight program ... has the potential for ensuring U.S. leadership in space into the future," University of Michigan Professor Len Fisk told Xinhua in an email.
Buzz Aldrin, who landed on the moon with Armstrong during the 1969 Apollo 11 mission, also thought Mars is "the next frontier for humankind" and he hoped NASA "will embrace this new direction as much as I do."