Big Strides Made in Tracking Near-Earth Asteroids, NASA Scientist Says

NEW YORK — Humanity has made substantial progress in the hunt for near-Earth asteroids that could potentially pose a grave threat to the planet, NASA's chief space rock hunter said Monday (Jan. 14).

Don Yeomans, head of NASA's Near-Earth Object Program, told a crowd here at the American Museum of Natural History that it is the smaller asteroids, not giant space rocks, that are difficult to spot.

"It’s unlikely that we'd miss a big one," said Yeomans, who has written a new book on near-Earth asteroids "Near Earth Objects: Finding Them Before They Find Us" (Princeton University Press 2013). “It’s the small ones that sneak up on us.”

Yeomans' office at NASA's Jet Propulsion Laboratory in Pasadena, Calif., is devoted to finding near-Earth objects (which includes asteroids and comets) and plotting their positions over time. A few of the more notable asteroids NASA has placed on the "cleared" list in the past year include such high profile space rocks as the asteroid Apophis, which will swing extremely close to Earth in 2029 and return in 2036. All told, astronomers have found 90 percent of the large asteroids whose orbits bring them close to our planet.

Apophis was cleared of concern last week when it made a distant flyby of Earth, which allowed astronomers to make new observations that helped complete rule out an impact threat in 2036. Previous observations had already ruled out the 2029 flyby.  [See Photos of Giant Asteroid Apophis]

In the near-future, as in this year, there will be other asteroids giving the Earth a close shave, said Yeomans.

On Feb. 15, the 164 foot (50 meters) asteroid 2012 DA14 will pass the Earth at a range of about 17,200 miles (27,680 kilometers), well inside the orbit of geosynchronous GPS navigation and communications satellites that fly about 22,370 miles (36,000 km) above the planet. Asteroid 2012 DA14 also poses no threat of impacting Earth during the flyby.

Yeomans and his colleagues can take close looks at near-Earth objects using advanced radar technology. By sending a beam in the general direction of an asteroid or comet, researchers can measure how long it takes for the beam to leave and then eventually be sent back, to the receiver. Scientists then analyze the reflected signal to determine exactly how far away an asteroid is and gain a sense of the its structure.

From there, NASA researchers enlist the help of amateur astronomers for follow-up observations to determine the orbit of a newfound asteroid, paying particular attention to how close the orbit track comes to the Earth.

"We observe where these objects are in the sky and project their orbits on years into the future," Yeomans said.

If Yeomans and his team did see an asteroid headed for the planet, there are a few courses of action available to them. Landing a small probe on the asteroid to nudge it slightly off course could be one way, while other have suggested impacting the crater with a probe that would drastically change its orbit, he said.

You can follow SPACE.com staff writer Miriam Kramer on Twitter @mirikramer. Follow SPACE.com on Twitter @Spacedotcom. We're also on Facebook & Google+. 

Copyright 2013 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

View the original article here

NASA Space Exploration Workshop Discusses Moon vs. Asteroids (ContributorNetwork)

NASA conducted a workshop on the Global Exploration Roadmap, the plan for the human exploration of the moon, near Earth asteroids, and eventually Mars in San Diego, California on Nov. 14-16.

Kathy Laureni of NASA Headquarters and Roland Martinez of NASA's Johnson Spaceflight Center gave an audio presentation of the results of the workshop. There is an accompanying power point presentation.

What is the state of the roadmap as of the end of 2011?

As we've reported previously, the Future in Space Operations study group is still looking at two paths, Asteroids Next or Moon Next. However there seems to be a growing consensus that some kind of way-station at the L2 point where the Earth's and moon's gravity cancel one another out would be useful for sustained operations, either on the moon, toward asteroids, or both. This seems similar to the Nautilus-X concept that we have discussed previously.

What was revealed about the Asteroids Next path?

The participants are keenly aware of the fact that opportunities to visit near Earth asteroids are few and far between. If more of these asteroids were to be discovered, then the mission opportunities would increase. The idea of a prize competition for amateur astronomers to discover such asteroids was floated.

One of the other questions that have been raised, but not answered, is how astronauts will interact with asteroids? Will they directly explore them? Will they use tele-operated robots? Will they use a combination of the two? The notion that there should be robotic precursor missions to the target asteroids was also pretty much decided, in order to maximize the amount of science that could be done. Voyages to asteroids are good practice runs for deep space missions to Mars.

What about Moon next?

There is a growing realization that there are more opportunities for commercial participation on a lunar exploration program than on voyages to asteroids. In situ resource utilization is easier on the moon as well. The moon is accessible from Earth at will. The moon is a great test bed for sustained surface operations, basically learning how to live and work in space for the long term.

However trips to the lunar surface are still thought to be expensive. There was some discussion about how that cost could be mitigated, including the use of reusable landers and local resources, i.e. to create rocket fuel. There was also some discussion of using tele-operated robots from Earth or from the proposed L2 station.

What about the costs of all this?

Planners for deep space exploration are going to be keenly aware of cost issues. If something costs more than the participating governments are willing to pay it will not happen. Commercial and international participation will help to mitigate cost issues, however.

Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker. He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post , USA Today, the L.A. Times, and The Weekly Standard.

View the original article here