DARMSTADT, Germany - The European deep space probe Rosetta successfully completed a flyby of an asteroid millions of miles from earth, but its high resolution camera stopped shortly before the closest pass, space officials said Saturday.
Rosetta caught up with the Steins asteroid, also known as Asteroid 2867, just after 8:45 p.m. (1845 GMT) Friday in the asteroid belt between the orbits of Mars and Jupiter. The probe came within 500 miles (805 kilometers) of the asteroid — which turned out to be slightly larger than scientists expected.
Officials at the European Space Agency were not sure exactly what caused the camera to balk.
"The software switched off automatically," Gerhard Schwehm, the ESA mission manager and head of solar systems science operations told The Associated Press. "The camera has some software limits and we'll analyze why this happened later."
Another wide angle camera was able to take pictures and send them to the space center, Schwehm said.
At a news conference, Uwe Keller, the principal camera investigator, said despite the camera turning off about nine minutes before its closest approach, it switched back on again later and was now working well. Keller said he did not expect the camera setback to affect the rest of the mission.
Craters of different ages were found on the surface of the gray-colored asteroid, showing a "rich collisional history," Keller said.
The probe recorded more than 23 craters over 200 meters wide, with the biggest being about 1.2 miles (2 kilometers) wide.
According to measurements by the probe, the diamond-shaped asteroid turned out to be 3.1 miles (5 kilometers) in diameter, slightly larger than an earlier estimate of 3 miles (4.8 kilometers).
The Rosetta craft was launched in March 2004 from French Guyana, and is now about 250 million miles (402 million kilometers) from Earth.
Schwehm said the historic mission could give astronomers crucial clues to help them understand the creation of the solar system.
"Dead rocks can say a lot," he said.
Rita Schulz, a Rosetta project scientist, said data from asteroids and comets was particularly valuable because they are made of galactic matter that helped create the planets in our solar system.
"Asteroids are a sort of memory, or the DNA, of the solar system," Schulz said.
Up until now, astronomers analyzing asteroids have had to work with limited data from brief flybys, such as when ESA's Giotto probe swept by Halley's Comet in 1986, photographing long canyons, broad craters and 3,000-foot (1000-meter) hills.
As planned, the Rosetta lost its signal to Earth for about an hour-and-a-half Friday night as engineers turned it away from the sun and the craft zoomed through space too fast for its antennae to transmit any signal.
At 10:15 p.m (2015 GMT) Friday the craft resumed transmission, signaling that the exercise was largely successful — news cheered by ESA engineers and technicians.
Yet there was another setback Friday night as data was sent to antenna stations far from Europe.
A NASA laboratory in Goldstone, California was having problems cooling one of its antennas in the summer heat and had to switch the ESA project to another antenna, delaying the analysis of some data by several hours.
Rosetta data was also transmitted to an antenna in New Norcia, western Australia.
Data from its working camera was being processed Saturday at the Max Planck Institute in Lindau, southern Germany, while further infrared data collected by the probe was being analyzed at the Instituto Nacionale di Astrofisica in Rome.
The Steins asteroid was Rosetta's first scientific target as it enters the asteroid belt en route to its destination, the comet 67/P Churyumov-Gerasimenko. Rosetta is scheduled to reach the comet in 2014.
Between now and then it will perform some gravitational experiments before going into hibernation, Schwehm said
The European Space Agency is supported by 17 countries including Germany, France, Ireland and the Netherlands. It cooperates with NASA, the European Union, European national space agencies and international partners. It's expected the ESA will become the European Union space agency in the near future.