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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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NEAR Spacecraft to Flash by Earth
21 January 1998 7:00 pm
After having successfully reconnoitered its first asteroid last year, NASA's Near Earth Asteroid Rendezvous spacecraft, or NEAR, will flash into view late Thursday night and early Friday morning across much of the United States. NEAR will swing within 540 kilometers of Earth's surface on its way to a close encounter with another asteroid, Eros. NEAR's solar panels will reflect the sun's light during its swift passage, treating observers to an ephemeral "sunglint" as bright as the night's most brilliant stars Last June, the $210 million spacecraft flew within 1200 kilometers of the asteroid Mathilde, dazzling planetary scientists with images of a primitive and severely battered object (Science, 4 July 1997, p. 30). NEAR's views of Eros, which it will orbit starting in January 1999, are expected to be 50 times sharper. A full year of data promises to reveal much about Eros's origins and composition: Some researchers speculate that it may be a floating "rubble pile." NEAR's mission to Eros, which orbits the sun between Earth and Mars, will end with an attempt to land on the asteroid's surface.
Tomorrow's slingshot around Earth will send NEAR on the proper trajectory to Eros while accelerating the craft to more than 46,000 kilometers per hour. During the swing-by, project scientists will calibrate NEAR's timing clock and check its navigation via a series of slight changes in the spinning flywheels that control NEAR's orientation. The craft will direct a beacon of reflected sunlight on a wavy path across the United States, between 1:25 a.m. and 1:48 a.m. EST on Friday, appearing as a slowly moving new "star" in the constellation Perseus. The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, which manages the mission, has posted detailed star charts and viewing times on its Web site.
David Dunham, NEAR's mission design chief, will coordinate a national network of amateur astronomers to observe the apparition. "If the solar panels aren't perfectly aligned, the 'star' will brighten in steps," Dunham explains. "Precise timings of the brightness pattern will help us align the panels." NEAR also will produce a movie of Earth during its flyby, with an especially stunning view of Antarctica as the spacecraft recedes from Earth.