(AFP/Getty Images) (AFP/Getty Images)

The NASA budget would shrink slightly under President Obama’s budget proposal. The White House is asking for $17.7 billion in funding, down about $50 million from what the agency received in 2012.

The proposed NASA budget includes $78 million, little more than starter money, for a mission that would use a robotic spacecraft to lasso a small asteroid and tug it back to a stable orbit a bit farther than the moon from Earth.

Astronauts could then visit the asteroid in a spaceship under development. But the money allotted to the program is slight enough that it gives the administration an out if technical problems scrap the project.

The budget blueprint says the $78 million would “develop needed technologies and study alternative approaches for a robotic mission to rendezvous with a small asteroid – one that would be harmless to Earth – and move it to a stable location outside the Moon’s orbit.”

NASA’s public affairs staff points out that the total expenditures on new asteroid-related projects is $105 million, including funding for research on identifying potential hazards to the planet from near-Earth asteroids. NASA has also spent two years developing the heavy-lift rocket and crew capsule necessary to perform deep-space missions, such as a rendezvous with an asteroid.

The president’s budget also includes a whack at a high-profile element of NASA: Planetary science, including the Mars program that last year put the rover Curiosity on the red planet. The proposal would cut Planetary Science dramatically, from $1.5 billion in 2012 to 1.217 billion in the coming fiscal year.

NASA administrator Charles Bolden said in a news conference that this was primarily the result of finding cheaper ways to achieve the same goals within the agency.

“We have now found ways to be much more frugal,” Bolden said.

NASA says much of the reduction comes from a drop in funds needed for the Mars rover program, which had caused a spike in the Planetary Science outlay in previous years. The reduction in funding “is part of the normal development cycle,” a NASA spokesman said by e-mail.

But Bill Nye, the “Science Guy” who is CEO of the Planetary Society, which advocates for robotic space exploration in the solar system, expressed his displeasure in a blog post Wednesday on the organization’s Web site. The budget cut, he wrote, “will strangle future missions and reverse a decade’s worth of investment building the world’s premier exploration program.”

He added: “NASA got approval to pursue a mission to capture and move an asteroid. This is intriguing and will receive a good deal of press coverage. But the disproportionate cuts to planetary science are disappointing and must get coverage, too. NASA did not get the message from Congress and the public about their wishes for missions to distant worlds.”