Figure 1	Figure 2

Observations from NASA's Spitzer Space Telescope reveal new information about the structure of 2011 MD, a small asteroid being considered by NASA for its proposed Asteroid Redirect Mission, or ARM. Spitzer's infrared images helped reveal that this asteroid consists of about two-thirds empty space. There are several possible structures for such an asteroid, two of which are illustrated here: a fleet of flying boulders (left) and a solid rock with a halo of fine debris (right).

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer.