Sidestepping Galileo's Jammed Antenna

Article excerpt

After several failed attempts to free Galileo's stuck main antenna, scientists last week revealed their plant for continuing the spacecraft's mission to Jupiter without it.

The main antenna, which resembles a large umbrella, failed to open in April 1991 after two of its ribs jammed. Since then, scientists have used Galileo's two smaller, low-gain antennas to transmit data to Earth. While this antennas have performed well so far, schientists worried that when Galileo begins orbiting Jupiter in 1995, the craft's experiments would flood the antennas with more data than they could handle.

Now NASA officials say that a few high-tech tricks could soup up Galileo's communication system to handle much of the data. "The good news we have today is that we have found a way to accomplish the majority of the orbiter's objectives," Galileo project manager WilliamJ J. O'Neill of NASA said at a press conference last week. In fact, Galileo could still complete up to 70 percent of its experiments without the main antenna, mission scientists say.

Researchers plan to boost the performance of the smaller antennas in two ways. First, Galileo's on-board computer would be reprogrammed to squeeze data into fewer computer bits, enabling scientists to send back more images and sensor information. …