NASA Asteroid Mission: It's all NASA can afford - NASA Chief Bolden

A NASA plan to send astronauts to an asteroid was met with skepticism Wednesday when NASA Chief Charlie Bolden presented the idea to top space officials in Congress.

The asteroid mission, unveiled a few weeks ago, would send a NASA probe to capture a small asteroid and drag it to a point near the moon so astronauts riding a new rocket and capsule could visit it, possibly as soon as 2021.

"The goal is (to) remain the world's leader in exploration," Bolden said. But members of the U.S. House science committee took issue with the project's cost and feasibility - and questioned why the agency wasn't planning a return to the moon en route to an eventual mission to Mars.

The NASA chief delivered a blunt reply: It's all NASA can afford. "I need money to go to the moon," Bolden said.

As part of its 2014 budget proposal, the White House wants NASA to spend $105 million next year to begin planning the asteroid mission, which could cost upward of $2.6 billion.

Broadly, the administration envisions sending a probe as soon as 2017 to capture a 25-foot, 500-ton asteroid and tug it near the moon - possibly to a spot about 277,000 miles from Earth that would use competing gravitational forces to allow it to "sit" there.

Astronauts flying NASA's new Orion capsule and Space Launch System (SLS) rocket then would visit it to take samples and possibly set foot on its surface.

In addition to scientific benefits, Bolden said an asteroid trip would serve as a steppingstone for an eventual Mars mission while also teaching NASA engineers how to divert an asteroid in case one ever threatened Earth. He called it "an unprecedented technological challenge."

AMS Dark Matter: NASA Chief Speaks Out

The news today (April 3) that the International Space Station has played a pivotal role in what could be one of the biggest leaps forward for astrophysics has left the NASA Administrator with nothing but high praise.

The news stems from the station's Alpha Magnetic Spectrometer, which detected signals that just might be evidence of dark matter particles colliding and annihilating each other. (Of course, it could be something else, too.

The science team has not yet confirmed the signal is definitely from dark matter, but it is a tantalizing possibility.)

Here's what Bolden says about today's AMS announcement, which NASA sent out to reporters this afternoon:

"The AMS cosmic ray particle results announced today could help foster a new understanding of the fields of fundamental physics and astrophysics. I am confident that this is only the first of many scientific discoveries enabled by the station that will change our understanding of the universe. Multiple NASA human spaceflight centers around the country played important roles in this work, and we look forward to many more exciting results from AMS. "

"For more than 50 years, NASA has pushed the boundaries beyond Earth to unveil the underlying architecture of the cosmos, revealing new knowledge about our place within it. The International Space Station is a gateway to the universe, teaching us how humans can live, work, and thrive in space as we endeavor to venture deeper into the solar system. "

"It's a remarkable testament that the orbital laboratory could play such an important supporting role in research at the very smallest scale of the physical universe. It's proof positive the space station is humanity's greatest achievement in low-Earth orbit."

The Alpha Magnetic Spectrometer is a complicated (and expensive) instrument launched to the space station in May 2011 on one of NASA's last-ever shuttle missions. The $2 billion instrument is the result of 16 years of work by 200 scientists from 16 different countries and 56 different institutions.