Continuing technology glitches aboard the Hubble Space Telescope -- this time balky gyroscopes -- may push the National Aeronautics and Space Administration into an emergency rescue mission a year sooner than the planned 1993 flight to fix flawed optics.
Project managers may face a Hobson's choice: fix the gyroscopes, whose complete failure would end the Hubble's usefulness, and live with the degraded performance of the flawed main mirror, or gamble that neither the gyroscopes nor the oscillating solar arrays will fail so catastrophically they cut short Hubble's life.
Manufacturing has begun on a new Wide-Field Planetary Camera and a 700-pound "costar," which is to place postage-stamp-sized mirrors in front of some of the Hubble's cameras to correct its myopic vision. The European Space Agency, which built the solar arrays, is working on versions to eliminate the panels' frustrating flexing as the Hubble moves in and out of sunlight. Both of those efforts were targeted for a late-1993 or early-1994 launch date. Whether NASA and the European agency can ready the complex hardware for a late-1992 emergency gyroscope repair is questionable. Besides, NASA lacks funds for two repair flights.
For now, NASA engineers are studying the puzzling gyroscope RTC failures. The two which failed had undergone the longest testing, and the type of gyros used typically lasts up to 14 years. A third "hiccuped" recently, indicating it also could be failing. The Europeans believe their arrays will stand up to the unexpected flexing without a major stress failure that would shut off all power to the telescope, a possibility that NASA must weigh carefully as it makes the "go/no go" decision.
Such disappointments obscure the discoveries scientists are making with the flawed Hubble, still the best optical telescope available. From finding a star "incredibly rich in platinum" to finding a galactic "jet stream" moving hundreds of thousands of miles per hour to making strikingly sharp pictures of objects in our own solar system, the Hubble's mirrors are spotting objects never before seen. A rushed launch to repair the gyroscopes might force Hubble scientists to emulate Desert Storm troopers, who, faced with incoming artillery fire as they struggled to install a complex digital communications processor -- a job normally done in two and a half days -- finished the work in 30 minutes.
Sometimes a situation becomes do or die. Let's hope the Hubble's doesn't get so desperate.