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Close Encounters Of The Eros Kind

By CBSNews.com staff CBSNews.com staff

February 10, 2000 / 4:57 PM EST / CBS

The Near Earth Asteroid Rendezvous spacecraft is in orbit around the asteroid 433 Eros Monday, reports CBS Space Consultant Bill Harwood.

After a near-flawless rocket firing, the robot craft became the first spacecraft to orbit an asteroid, settling into a Valentine's Day rendezvous with a space rock named for the Greek god of love.

The NEAR spacecraft automatically fired for 57 seconds and then signaled success to Earth.

Running a year late because of a technical glitch, a small golf cart-sized probe slipped into orbit around a slowly tumbling asteroid twice the size of Manhattan, giving NASA a welcome Valentine's Day success after the back-to-back losses of two Mars probes last year.

The $210 million NEAR spacecraft successfully braked into orbit around the appropriately named Eros four years after launch from Cape Canaveral on Feb. 17, 1996. Traveling at 186,000 miles per second, radio signals from NEAR confirming the successful orbit insertion rocket firing took 14 minutes to reach Earth.

After additional signals reached Earth, Robert Farquhar, NEAR mission manager at Johns Hopkins University's Advanced Physics Laboratory, told scores of waiting scientists and guests: "The NEAR spacecraft is in orbit around the asteroid Eros! This is the first time any spacecraft has been in orbit around a small body."

Engineers, flight controllers and guests burst into enthusiastic applause. Preliminary data indicated the rocket firing changed the spacecraft's velocity to within 0.04 percent of the desired target, a near-perfect orbit insertion maneuver. NASA Administrator Daniel Goldin and Sen. Barbara Mikulski, D-Maryland, shared an enthusiastic high five in the APL control room at Johns Hopkins.

"You don't always get two chances at love," Goldin said of NEAR's initial failure to get into orbit around Eros in December 1998. "We had one shot and we missed it and we had another opportunity. The team here at APL has done just an outstanding job. It's not how you deal with success, it's how you deal with failure, or the potential for failure, and coming back is just wonderful."

Said Mikulski, whose district includes Johns Hopkins, "Happy Valentine's Day to all the wonderful staff at NASA and the Applied Physics Lab of Johns Hopkins that have brought America a space valentine, its first view of an asteroid up close and personal."

Initial indications are the 1,800-pound spacecraft performed as planned, slowing just enough to slip into the grasp of Eros' feeble gravity, circling the peanut-shaped rock at what amounts to walking speed on Earth. If all goes well, NEAR will spend the next year probing the cratered asteroid with a battery of high-tech instruments to learn more about its origin and evolution. In so doing, scientists hope to gain insights into the formation of the solar system some 4.5 billion years ago and, by extrapolation, the formation of solar systems across the universe.

"It's eciting, important science, new science," mission scientist Andrew Cheng said before launch. "We're going somewhere we have never gone before, we're doing things that have never been done before, principally orbiting an asteroid. We're also making measurements that have never been possible before."

Near-Earth asteroids, which orbit the sun within about 120 million miles, are thought to be the remains of dead comets or fragments of debris blasted free during collisions in the main asteroid belt between Mars and Jupiter. Named after the Greek god of love, 433 Eros is the most studied member of this class. The NEAR spacecraft already has snapped some 8,000 photographs of the asteroid on its way to the encounter, including one showing a three-mile-wide heart-shaped crater.

"We need to study these asteroids," Mikulski said. "We need to know who they are and what they are. This may be the 'love asteroid,' complete with a valentine-shaped crater, but all of America wonders will we ever be hit by one...By using this first attempt here, we'll be able to identify asteroids much earlier as they come towards Earth, be able to analyze what they're made of so we'll know how to deflect them, and America will be safe because of this."

Eros was discovered in 1898. It takes 1.81 years to complete one orbit of the sun at a distance of between 1.13 and 1.8 astronomical units [an astronomical unit is the distance from the Earth to the sun, or about 92 million miles]. Eros measures about 21-by-8-by-8 miles and rotates about its axis every 5.25 hours.

During the course of its mission, Cheng said, NEAR will provide the "first close-up look at an object which may preserve materials dating all the way back to the origins of our solar system to the time when the planets, including Earth, were first forming."

Data from NEAR should allow scientists to measure the composition of the asteroid, "finding out what minerals and elements it contains," Cheng said. "We'll make a map showing where they are. We're also going to be looking at the surface features and seeing if we can understand how it came to be the way it is."

NEAR is a three-axis stabilized satellite massing about 1,800 pounds. It is equipped with four solar panels that will generate about 1,800 watts at a distance of one AU from the sun. It is equipped with a half-dozen high-tech instruments.

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