Engineers Fix Antenna on Hubble Telescope

Engineers fixed a jammed antenna on the $1.5-billion Hubble Space Telescope early today and said they are well on the way to recovering full use of the vital communications system on the orbiting telescope.

The telescope has not been able to communicate with the ground through its high-speed antenna since the astronomy satellite was released from the space shuttle Discovery last Wednesday. Engineers working on the problem discovered that an antenna had been jammed by a cable.

The National Aeronautics and Space Administration said commands sent during the night “gingerly” repositioned “high-gain antenna No. 2.”

“Successful centering of the antenna marked a major milestone in the process of recovery use of the high-gain antenna system,” NASA said.

The telescope has two high-gain antennas, which are supposed to link it with orbiting relay satellites. Without the antennas, it was impossible for engineers to proceed with the calibration that was supposed to be started almost immediately.

Two attempts to use the antenna system were unsuccessful Saturday because a computer sensed the obstruction. If engineers had sent commands to force movement of the antennas, the computer system would have shut itself down as it did earlier.

Engineers at Goddard; the Marshall Space Flight Center in Huntsville, Ala.; Lockheed Missiles & Space Co. in Sunnyvale, Calif., and elsewhere, pored over computer simulations of the antenna and data to try to solve the problem.

“One control center engineer even went to a toy store, purchased an assembly kit consisting of plastic sticks and joints and built a model of the antenna . . . assembly with the components and a piece of lamp cord,” officials said.

Having solved the nagging antenna problem at 10:25 p.m. Sunday, engineers then switched on a science computer on the 12-ton telescope orbiting 381 miles above Earth and took initial steps to activate its five high-tech instruments.