NEO Asteroid Detection: NASA's Arecibo now and ATLAS in the future

Arecibo Radio Telescope

The NEO program at NASA currently detects and tracks Earth-approaching asteroids and comets with land-based and orbiting telescopes. Scientists estimate their mass and orbit to gauge whether they pose a danger.

With this system, the Arecibo radio telescope in Puerto Rico, which has an antenna 305 meters in diameter, can observe with great sensitivity a third of the night sky and detect asteroids that are on the large side.

All asteroid observations made anywhere in the world by telescopes, even by amateur star gazers, must be passed on to the Minor Planet Center, which is financed by NASA and run by the Smithsonian Astrophysical Observatory for the Paris-based International Astronomical Union.

But in times of tight budgets like these, NASA is trying to develop other systems specifically capable of tracking small objects in space.

NASA is financing to the tune of $5 million a project at the University of Hawaii called Atlas, or Asteroid Terrestrial-Impact Alert System.

Researchers say ATLAS, which will monitor the entire visible sky every night, will be able to detect objects 45 meters (yards) in diameter a week before they hit our planet.

For those measuring 150 meters (yards) in diameter, the system -- which could be operational in late 2015 -- will give a three week heads up.

The goal is to find the objects and give enough advance warning for measures to be taken to protect people, said John Tonry, the principal investigator at ATLAS.

The system has enough sensitivity to detect a match flame in New York City when viewed from San Francisco, for instance.

"That's enough time to evacuate the area of people, take measures to protect buildings and other infrastructures and be alert to a tsunami danger generated by ocean impacts," according to the ATLAS website.

ATLAS will complement the Institute for Astronomy’s Pan-STARRS project, a system that searches for large “killer asteroids” years, decades, and even centuries before impact with Earth.

Whereas Pan-STARRS takes a month to complete one sweep of the sky in a deep but narrow survey, ATLAS will search the sky in a closer and wider path to help identify the smaller asteroids that hit Earth more frequently.

Radar Clicks Asteroid Images

Radar Clicks Asteroid Pic

Near-Earth asteroid 2005 YU55 was "imaged" by the Arecibo Radar Telescope in Puerto Rico on April 19. Data collected during Arecibo's observation of 2005 YU55 allowed the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory to refine the space rock's orbit, allowing scientists to rule out any possibility of an Earth impact for the next 100 years.

The space rock was about 2.3 million kilometers (1.5 million miles) from Earth at the time this image of the radar echo was generated.

The ghostly image has a resolution of 7.5 meters (25 feet) per pixel. It reveals 2005 YU55 as a spherical object about 400 meters (1,300 feet) in size.

Not only can the radar provide data on an asteroid's dimensions, but also on its exact location in space. Using Arecibo's high-precision radar astrometry capability, scientists were able to reduce orbit uncertainties for YU55 by 50 percent.