Reply #17: A definite maybe [View All]

Sept. 20, 2002: Something odd is circling our planet. It's small, perhaps only 60-ft long, and rotates once every minute or so. Amateur astronomer Bill Yeung first spotted the 16th magnitude speck of light on Sept. 3rd in the constellation Pisces. He named it J002E3.
Automated asteroid surveys scan the skies every few weeks, yet there was no sign of Yeung's object earlier this year. "It must have entered Earth orbit recently," says Paul Chodas of NASA's Near-Earth Object Program at JPL. "But it doesn't match any recently-launched spacecraft."
In other words, it's a mystery.
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Could it be an alien spaceship? "If it is," says Chodas, "the aliens aren't good pilots. J002E3 is in a chaotic orbit. It loops around Earth once every 48 days or so, coming as close to our planet as the Moon and ranging as far away as two lunar distances." There's no evidence that the speck is moving under its own power. The orbit is constantly changing because of gravitational perturbations by the Sun and Moon.
At first Yeung and others thought J002E3 might be a small asteroid--a reasonable guess. The object is as bright as a 30m-wide space rock and it's moving about as fast as an asteroid should move. Mars and Jupiter have captured asteroid moons before; perhaps Earth had done the same.
It was a good idea, except for the paint.
That's what University of Arizona astronomers found on Sept. 12th when they measured the spectrum of sunlight reflected from J002E3. "The colors were consistent with ... white titanium dioxide paint--the type of paint NASA used on Apollo moon rockets 30 years ago," says Carl Hergenrother, who conducted the study with colleague Robert Whiteley.
<snip>
So, J002E3 might be a spacecraft after all--an old one from Earth. Where has it been all these years?
"Orbiting the Sun," answers Chodas. "I've traced the motion of J002E3 backwards in time to find out where it's been," he explains. Apparently, J002E3 left Earth in 1971, went around the Sun 30 or so times, and came back again. Chodas, a expert in planetary motion who has seen plenty of complicated orbits, says "I've never seen anything like this."
At first glance, J002E3 would seem to be from Apollo 14. That mission began in January of 1971, and according to Chodas' calculations J002E3 broke out of Earth orbit in March of the same year. There's a problem, though: NASA has accounted for all the big pieces of the Apollo 14 spacecraft. None are missing.
http://science.nasa.gov/headlines/y2002/20sep_mysteryobject.htm