From: JPL Universe

Several teams from JPL are contributing to the first-ever spacecraft
mission to orbit an asteroid.

On Feb. 14, the Near Earth Asteroid Rendezvous (NEAR) mission, managed by
Johns Hopkins University’s Applied Physics Laboratory, went into orbit
around asteroid 433 Eros, a potato-shaped, 34-kilometer-long (21-mile) body
about 256 million kilometers (160 million miles) from Earth.

JPL teams are providing critical support to the mission in these areas:

* Navigation

* Radio science (including gravity science)

* Deep Space Network tracking

* Multispectral imager and near-infrared spectrometer

* Shape modeling working group

* Mission design (in conjunction with APL)

Dr. Don Yeomans, manager of JPL’s Near-Earth Objects Program Office, is
radio science team chief for NEAR, which will study Eros for a year,
gradually dropping its elliptical orbit to as low as 1 kilometer above the
surface by mission end. Another member of the team, Jon Giorgini of the
Navigation and Mission Design Section 312, said the team is involved in
tracking the asteroid’s rotation state and gravity field, as well as the
trajectory of the spacecraft in its orbit around Eros.

The navigation team has been involved with NEAR since its inception,
including determining requirements for the spacecraft and selecting the
target asteroid. The team, headed by JPL’s Dr. Bobby Williams, processes
radiometric data through the Deep Space Network and optical data through
NEAR’s onboard camera.

“This mission is not only the first to orbit an asteroid, it’s also the
first to use landmark tracking for deep-space navigation,” Williams said,
noting that craters on the rock are identified and then used for points of
reference.

Williams said the spacecraft’s current transfer orbit will continue through
about March 10, at which point it will be lowered to about 200 kilometers
(125 miles).

He said NASA is considering a crash landing on Eros at the end of the
mission next February, when the spacecraft will be out of fuel.

Images of Eros and other information about the mission
are available online at http://near.jhuapl.edu.