Love at first orbit?
Is the timing of NASA's latest space venture a coincidence, or a great publicity stunt? The spacecraft "NEAR" which is currently on its way to orbit around the asteroid "Eros" is due to reach its target bang on February 14, St Valentines Day.
Named after the Greek god of love, Eros is the first asteroid to be orbited by a NASA mission. NEAR (Near Earth Asteroid Rendezvous) is expected to fly directly between Eros and the sun, late on the eve of Valentine's Day.
NEAR's infrared spectrometer will take advantage of good light conditions to take observations of Eros' northern hemisphere. This will provide information on the 33x13x13km asteroid's mineral composition.
Then the following day, February 14 NEAR is expected to be 333 kilometers from the center of Eros, when it will fire its hydrazine engines to slow it enough to be captured by the asteroid's weak gravitational pull. During the first few weeks after achieving orbit the spacecraft will slowly descend toward the asteroid.
Because the asteroid is irregularly shaped and rotating (it rotates once every 5.27 hours), this early stage of the mission can be very tricky, says Dr Robert Farquhar, NEAR mission director.
"No one has ever orbited a small body in space," Farquhar says. "The orbital stability is rather tenuous, and as we travel around Eros our navigation manoeuvers must be perfect to keep us from crashing into it."
NEAR will spend a year scrutinizing the potato-shaped space rock to learn about its chemical and physical features and evolutionary history. The mission is being conducted by Johns Hopkins University Applied Physics Laboratory, Laurel, MD.
NEAR was launched February 17, 1996, from Cape Canaveral Air Station, Florida. Its original rendezvous date of January 10, 1999, was postponed when a firing of the spacecraft's bipropellant engine, designed to put the spacecraft on target for the rendezvous, exceeded preset acceleration limits and caused the spacecraft to retreat into safe mode.