NEAR Rendezvous Burn a Success.

By Keith Cowing
February 2, 2000
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NEAR at Eros

[02 February 2000] According to a press release from the Applied Physics Laboratory at Johns Hopkins University, “The NEAR spacecraft went into a “safe” hold this morning while preparing for today’s scheduled rendezvous burn. The NEAR team will attempt the maneuver tomorrow and the mission remains on schedule for the Valentine’s Day encounter with asteroid Eros.”

“The rendezvous burn is a braking maneuver designed to slow NEAR’s speed relative to Eros (from 45 mph to 21 mph) and refine its trajectory toward the
asteroid. The spacecraft’s onboard computer initiated the safe mode at 5 a.m. EST during a routine procedure that precedes a change in NEAR’s velocity. Mission operators stayed in constant touch with NEAR and the spacecraft appears healthy, though the NEAR team is looking into potential causes of the problem.”

[03 February 2000] Update: According to a press release, “Preliminary indications show the NEAR spacecraft is on a steady path to Eros, after a braking maneuver today adjusted its approach speed and trajectory toward the
large asteroid. At noon EST, NEAR’s medium-sized thrusters fired for 90 seconds and eased the spacecraft from 43 mph (relative to Eros) to 18 mph. The maneuver also moves
NEAR’s trajectory about 60 miles (100 kilometers) closer to its target.

The operation was a slightly modified version of the rendezvous burn scheduled for Feb. 2, which was canceled after NEAR went into “safe” hold early yesterday
morning. Mission operators at the Applied Physics Laboratory sent new commands to NEAR late last night, dividing the original Feb. 2 maneuver into two parts. A
second burn on Feb. 8 will bump NEAR’s approach speed to 22 mph and put it back on its original track to the asteroid.”

NEAR has been making measurements of Eros as it makes its approach. Included in these measurements are a series of photos that show how Eros rotates. These images will be used as NEAR’s final trajectory is plotted by allowing mission managers to scan for possible moons or other debris in the immediate vicinity of NEAR that might pose navigation or collision hazards.

Eros According to the Applied Physics Laboratory at Johns Hopkins University, the image (to the left) of Eros “was taken on January 12, 2000 from the Near Earth Asteroid Rendezvous (NEAR) spacecraft. The image was taken at a range of 27,200 miles (45,350 km) while the spacecraft approached the asteroid at a velocity of 43 miles per hour (19 meters per second). At that time NEAR was 170 million miles (274 million kilometers) from Earth. Eros is a very elongated object about 21 by 8 by 8 miles (33 by 13 by 13 kilometers) in size.”

More images of Eros have since been released. A short movie created from 720 still images taken at a distance of 17,800 miles (28,600 km) from Eros on 22 January shows how Eros rotates end over end. A subsequent collection of images taken on 29 January 2000 at a range of 17,100 km by NEAR’s multispectral imager on shows even more detail about the shape of Eros. The clarity of these images will continue to increase as NEAR moves in on Eros.

On 14 February 2000, after a year’s delay, the NEAR spacecraft will begin the intricate dance of settling into an orbit around asteroid 433 Eros. If NEAR accomplishes its main task, it has the potential of utterly rewriting our understanding of asteroids.

So far we’ve only flown past asteroids and snapped a few pictures. NEAR will orbit Eros and map it in unprecedented, intimate detail. If all works out after its baseline mission is completed, NEAR will circle in closer and closer until mission controllers may actually attempt a quasi-soft landing (i.e. a slow motion collision) on Eros itself.

SpaceRef will attempt to depict every aspect of this mission – from its prelude, the discovery of Eros in 1898, to NEAR’s arrival and collection of data from Eros itself a century later in 2000. Stay tuned.

° NEAR Rendezvous Burn a Success, Johns Hopkins University

° Rescheduled Rendezvous Burn to Keep NEAR on Course, Johns Hopkins University

° NEAR Rendezvous Burn Delayed, Johns Hopkins University

° NEAR Image of the Day 31 January 2000, Johns Hopkins University

° NEAR image of the day for 2000 Jan 27, Johns Hopkins University

° NEAR Background Press Kit –3.7MB PDF file, , Johns Hopkins University

° Shape of Asteroid 433 Eros from Inversion of Goldstone Radar Doppler Spectra, NASA JPL

° NEAR image of the day for 2000 Jan 14, Johns Hopkins University

° NEAR image of the day for 1999 Jan 21 (MPEG Movie, 2.3 MB file) , Johns Hopkins University

SpaceRef co-founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.