Astronomers have located the missing SOHO spacecraft, which suddenly went silent a month ago while observing the Sun.
Dr. Joseph B. Gurman, the NASA project scientist for the joint United States-European Solar and Heliospheric Observatory project, said today that space agency officials still hoped to regain control of the scientific observatory. ''We are a little better off today than we were a week ago,'' he said in an interview.
The National Aeronautics and Space Administration and the European Space Agency announced that ground-based radio telescopes situated thousands of miles apart were able to find the $1 billion satellite last Thursday by sending radar signals into the area of space where the craft should have been.
Researchers at the National Astronomy and Ionosphere Center in Arecibo, P.R., used their radio telescope, which is 990 feet in diameter, to transmit radar signals toward SOHO's location, almost a million miles from Earth. NASA's 230-foot Deep Space Network dish in Goldstone, Calif., picked up signals reflecting off the satellite and was able to track it for more than an hour, scientists said.
The spacecraft is very close to its original position and is turning slowly at a rate of about one revolution per minute, scientists said. This slow spin rate is encouraging, they added, suggesting that minimal structural damage has occurred to the craft. SOHO is equipped with special instruments to study sunlight at different wavelengths and to analyze particles and magnetic fields generated by the Sun.
The spacecraft orbits the Sun at a point between Earth and the Sun where the gravity of each body cancels out that of the other and keeps the craft in a stable spot.Continue reading the main story
SOHO was launched on Dec. 2, 1995, and was designed to stay operational for at least two years. Scientists had hoped to continue the mission into the next century as the Sun goes through a period of maximum activity.
Radio contact with the spacecraft was lost on June 24 when it was given erroneous computer instructions, causing the craft's solar power panels to switch positions away from the Sun. Deprived of sunlight, the satellite lost power and stopped responding to orders from Earth.
Dr. Gurman, working at NASA's Goddard Space Flight Center in Greenbelt, Md., where SOHO is controlled, said engineers hoped that further radar observations would refine the craft's position and give more precise information on SOHO's orientation and spin. There is a possibility that the craft will slowly align its solar panels with the Sun over the next few weeks and get enough power to allow it to respond to commands, he said.Continue reading the main story