APL Press Release

Late Thursday, Jan. 22, the spacecraft approaches Earth over the Pacific Ocean traveling at about 20,000 mph. If there is no cloud cover, several geographic areas will be able to see reflections from the spacecraft's solar panels. These sunglints will be visible on the East Coast, Friday, Jan. 23, at about 1:30 a.m. EST, and on the West Coast about 15 minutes later; i.e., Thursday, 10:45 p.m. PST. See the Sunglint section for more details. For detailed close approach data, see this table .

Can you see it pass by at night?

Closest Approach
	The closest the spacecraft will approach Earth will be 333 miles, above Ahvaz in southwest Iran on Friday at 07:23 UT, (2:23 a.m. EST). By then the Earth's gravity will have accelerated the spacecraft to about 29,000 mph. This computer simulation shows the NEAR spacecraft at nearly 8,000 miles over the South Atlantic Ocean about 31 minutes after its closest approach over the Middle East. The beam from the spacecraft to southeast Africa shows the portion of Earth's surface seen by NEAR's imager. Click image to see more detail
	This computer simulation shows the NEAR spacecraft over Saudi Arabia at about two minutes past the closest approach. Click image to see more detail

Trajectory

By 7:00 p.m. (EST) Friday (midnight, UT), the spacecraft swings away from Earth, and it will have decelerated about 15,000 mph. The swingby will have changed the spacecraft trajectory to approximately 11° south of the Earth's ecliptic (the plane of the Earth's orbit around the sun). This aims the spacecraft toward its target -- the asteroid 433 Eros -- which the spacecraft will orbit to gather science data starting 10 Jan, 1999.

Ground Track
	This chart shows the path on the Earth (ground track) flown over by NEAR. Times shown are Universal Time (UT). Click image to see more detail. NEAR Earth Ground Track Data File:   HTML table   Excel (.xls) file   ESBGTRAK2.XLS

Instrument Tests

The Earth Swingby gives NEAR scientists the chance to test and calibrate their instruments onboard the spacecraft. Planned tests are as follows: NEAR Laser Rangefinder (NLR) Test:   The NLR operates in the infrared at 10,000 Angstroms (Å), so you can't see this with binoculars. The main purpose is to check the exact alignment of the laser, which after the vibrations of NEAR's launch, could be in error by more than 0.1° in an unknown direction. The laser beam is only 48" wide. The test will be LONG, lasting almost 6 hours, starting at 0h 55m UT starting 0.11° from the expected location. NEAR will then slowly spiral in to the center (the expected direction), reaching the center after 30 revolutions (each 6 minutes long) at 3h 50m UT. Then it will spiral out for another 30 revolutions until about 6h 45m UT. The same times and strategy will be used each night, but it will be conducted only on one selected night by a trigger command to enable the time-tagged, preloaded sequence. Multispectral Imager (MSI), and the NEAR-Infrared Spectrograph (NIS):   MSI is is a visible light camera that will help determine the physical characteristics of Eros. NIS will be used to study surface minerals. These instruments will be calibrated by comparing their readings of Earth's geological features with proven measurements of the same areas. These instruments will also be used to take images of the Earth along the spacecraft's path. The images will be combined to produce a movie from a series of images taken over Asia, Africa, and Antarctica, which will be released several weeks after the swingby. NEAR's Magnetometer:   Calibrated by comparing swingby data with known measurements of the Earth's magnetic field. X-Ray/Gamma-Ray Spectrometer (XGRS):   Observe celestial gamma ray bursts and to collect data on gamma ray and x-ray backgrounds. These data are needed so scientistscan better remove background impurities from the measurements to be made at Eros.

Sunglint Maneuvers

As the spacecraft approaches Earth, its almost 100 square feet of solar panels will be rotated to reflect sunlight to several regions of the U.S.A., providing a unique opportunity to see with the naked eye an interplanetary spacecraft flying through space. Although the spacecraft will be about 9000 miles over the North Pacific Ocean at the time, it is expected to briefly shine as bright as the star Capella, which is among the brightest stars in the sky. Starting about 06:23 UT, the spacecraft will be maneuvered to measure the misalignment of the vectors normal to the solar panels and the +Z axis direction. Data obtained will also be useful in support of the next Trajectory Correction Maneuver, TCM-12, scheduled for February 4. Reflection from the spacecraft will be visible in many locations across the U.S.: Table of sunglint locations and times Diagram of sunglint paths across U.S. Star chart w/constellations - U.S. East coast Star chart w/constellations - U.S. West coast Star charts (more precise) for U.S. Locations Detailed star charts especially for telescope users and animated sunglint tracking images.