DATE=2/21/2000 TYPE=CORRESPONDENT REPORT TITLE=SHUTTLE (L) NUMBER=2-259392 BYLINE=DAVID MCALARY DATELINE=WASHINGTON CONTENT= VOICED AT: INTRO: Astronauts aboard the U-S space shuttle Endeavour have completed mapping the earth by radar and are preparing for return to Earth Tuesday. V-O-A Science Correspondent David McAlary reports. TEXT: Endeavour's crew has turned off two powerful radar systems that have been bouncing signals off Earth for nearly 10-days to create a precise three- dimensional topographical map of about 80-percent Earth's terrain. Thanks to a nine-hour extension that allowed mapping to continue into Monday, the instruments covered virtually 100-percent of the land area scientists had targeted. That includes territory as far north as Alaska and as far south as the tip of South America. Mission Control in Houston, Texas thanked the six Endeavour crewmembers for a job well done. // ROBINSON ACT // We would like to congratulate you on a flawless operation of this most sophisticated mapping instrument in the universe. The mapping data you have collected are some of the most valuable accomplishments in the history of space flight, and this topographic database will be a real treasure to the human race for many years. // END ACT // Scientists got more radar data than they had expected, after a technical problem last week raised the possibility imaging would have to be curtailed. A jet thruster used to stabilize the 60-meter radar mast failed. To compensate, shuttle pilots had to fire the orbiter's thrusters more often than planned. NASA controllers feared this maneuver might use too much fuel to assure Endeavour could safely manage an emergency. But by innovative fuel conservation measures, NASA restored the original time allotted to radar imaging. It then added nine-extra hours by eliminating a spacewalk astronauts were prepared to make if the 60- meter long radar mast failed to retract by itself. Mission managers said they were willing to take that slight risk to get the extra mapping, and would instruct the astronauts to eject the mast if necessary. In the end, the structure withdrew into its stowage compartment flawlessly, as flight controllers expected. Astronaut Janice Voss expressed the gratitude of the crew for the measures to save propellant - or prop as she calls it - and for the time added to the radar mapping mission. // VOSS ACT // We appreciate the efforts of all you folks on the ground to give us the prop to get these extra hours and to get all this great mapping done. In the true spirit of never give up, never surrender, we really appreciate all your hard work. // END ACT // Endeavour is scheduled to land Tuesday in Florida (at 4:52 p.m. EST). (SIGNED) NEB/DEM/RAE 21-Feb-2000 10:25 AM EDT (21-Feb-2000 1525 UTC) NNNN Source: Voice of America .