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Show DESERET NEWS SALT LAKE CITY, UTAH THURSDAY, DECEMBER 28; 1967 Vital Space Re-entry Jests By HAL KNIGHT Deseret News Science Writer Six years ago the U.S. launched its first man into space. Col John Glenn rode three orbits around the earth in his Mercury capsule. •" On the way down, the intense peed caused fric-ion in the atmos- >ere. The space-Craft glowed red hot and fell like a shooting star. Iii the midst of this anxious descent the ground Mr. Knight Stations lost radio contact with the astronaut. . A few minutes later communications were restored, but it was a scary moment. It was also a situation that would happen with every manned flight. Known as the "re-entry blackout," it Is caused by friction heat ionizing the atmosphere around the space capsule and cutting of communications. It meant that astronauts coming back SCIENCE IN THE NEWS to earth would always lose contact with ground stations and tracking equipment right at a most critical and dangerous moment. It also left a question mark as to the exact landing spot if the craft were slightly off course. However, the crucial problem may be on the way to being solved, thanks to tests with missiles • launched from Green River. Utah. In two launchings mis fall, the tracking stations at White Sands Missile Range (WSMR) in New Mexico have followed payloads from Green River all the way through the "blackout." Officials at WSMR report that this may mark the first time that telemetry equipment has tracked a vehicle all the way through re-entry. The data being tansmitted is different than voice transmission, but it "illustrates the feasibility of solving the problem of voice communication through the re-entry blackout period," one official said. Successful tests were carried out with four-stage Athena missiles being fired from Green River. Two stages loft the slender rocket high above the earth. The other two fire as the missile turns over and is headed back down to the ground. These boost the speed to the level of a spacecraft returning into the earth's atmosphere. : Four tracking antennas locked onto the signals from the Athena payload about 400 miles from the impact area and followed it all the way in. Some data was lost for two to four seconds of the re-entry and the signal was noisy at times, but telemetry tracking did occur all the way down. The breakthrough came as a result of WSMR efforts to change all telemetry operations from VHF radio (very high frequencies to UHF (ultra high frequencies). Oddly enough, the change is being made not because of the promise of bet- ter comm'unlcations but because of a Department of Defense order. That order calls for all telemetry equipment to vacate the crowded VHF band in favor of the less-used UHF by 1970 along with all military users. Although first results have been promising, there is still a long way to go. Work is being pushed at White Sands into related tracking communications problems. The success points up the value of the little-noticed launchings out of Green River. The town has become the major off-range arm of White Sands. Athena missiles are launched regularly from the site to WSMR, 450 miles away. The program is aimed at studying all kinds of re-entry problems involving communications, tracking, defense and attack. The Green River site, plus occasional launchings from: near Blanding, are the only overland missile routes fn the U.S., due mostly'to the sparse population of the Four Corners area. Remote and little-known as the region may be, it still plays a key role in space and missile research. |