It's only a hunk of rock in space. But scientists named it Eros — and fell in love with it.
Since last Valentine's Day, the asteroid Eros (named for the Greek god of love) has been circled by a robot probe called NEAR (for Near Earth Asteroid Rendezvous) Shoemaker.
"The mission has returned 10 times the data that we originally planned, because it turns out the spacecraft is just a joy to drive," says project scientist Andrew Cheng. "These are rocks that are older than any you can find on Earth, and they're rocks that date back to the beginning of the solar system, so that's why we're interested."
Scientists are interested in studying asteroids because some threaten to hit us.
The craft — roughly the size of a compact car — was launched into space on board a rocket in 1996, and has traveled 2 billion miles since then. It has taken thousands of pictures of Eros, a tumbling asteroid that is 21 miles long — roughly twice the size of Manhattan. But now, the NEAR mission is out of money, and the ship is almost out of fuel.
Attempting to Land
Mission director Bob Farquhar says controllers could have left the ship in orbit around Eros, but decided that a goodbye kiss would be nicer.
So today, they will fire the ship's engines ever so gently to bring it closer and closer to the asteroid's surface. If they do everything right, it will fall at a rate of less than 7 mph. And if they're really lucky, it will touch down intact, but the craft could also crash to the surface of Eros. The gravity on the asteroid is so weak that an astronaut who weighs 160 pounds on Earth would weigh 1 ounce there.
"If an astronaut were not careful, and leaped up with too much excitement, he could end up in orbit, that would be bad," says Cheng.
Scientists are hoping that the craft does not crash today.
"I have two sets of charts prepared for our press conference on Feb. 14. One of them has 'Historic First for Planetary Impacters' and another of them has 'Historic First for Planetary Landers,'" says Farquhar. "I want to be on the lander chart."
Sending Back Photos
As the ship descends, a camera mounted on its side will be taking the highest-resolution pictures of an asteroid in history. Starting at about 1:30 p.m., the photos will be streamed online, at http://near.jhuapl.edu in nearly real time. A landing is expected by about 3:05 p.m. today.
"We have an opportunity here to do unprecedented science," says Farquhar. "We can see little small pebbles, almost, with that resolution."
The scientists say they'll be surprised if they hear from the ship after it touches down. It was never designed to land — it doesn't even have legs.
Today's maneuver is particularly significant because, at 196 million miles from Earth, Eros is the most distant object on which a landing has been attempted.