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Aviation History
1964
1964 - 1484.PDF
HT International, 14 May 1964 825 THE X-248 ACCIDENT A group of NASA specialists, reporting on the accidental ignition of an X-248 solid propellant rocket motor in the spin test facility n Cape Kennedy on April 14, has recommended tests to determine whether static electricity caused the accident. The Orbiting Solar Observatory B spacecraft was mounted on top of its Delta third- stage motor when the motor ignited. The rocket tore away from the alignment stand on which it was mounted, hit the ceiling of the building, knocking off the spacecraft, and landed in a far corner. Eleven men working in the building were burned—two of them fatally—and the OSO B was badly damaged. The fact-finding group concluded that there were four possible reasons for the ignition of the rocket motor. These were heat, shock, outside radio signals, or an electrical impulse. The first three of these seemed unlikely. The room was air- conditioned and controlled for humidity and no floodlights were on; the propellant is not highly sensitive to jarring and the motor and spacecraft were stationary at the time of the accident; and no radio signals which could have caused ignition were reported by the USAF unit which monitors all radio signals at the Cape. At the time of the accident all power was switched off in the spacecraft, and the alignment rig consists of a fixed platform. It was thought possible, however, that static electricity could have built up in such a way as to cause ignition. A series of tests are to be made to determine sources of energies of static electricity which might have caused ignition. Until a final report is made, NASA will make no further flights using the X-248 motor. It has been used as the third stage of Delta and the fourth stage of Scout and was gradually being replaced by the newer X-258 rocket. The spin test facility was not extensively damaged in the accident. -AND X-258 DEVELOPMENT "Follow-on tests of in-flight characteristics" of the X-258 solid- propellant rocket motor were made in a four-stage Javelin (Argo D4) sounding-rocket firing from Wallops Island on April 15. These tests formed part of NASA's X-258 development for use in satellite launching vehicles and, possibly, for the sounding-rocket programme. As a secondary mission, the flight included a number of scientific investigations in the ionosphere. The Javelin, with the X-258 replacing the rocket's X-248 fourth stage, carried a 1201b payload of instruments and other equipment and reached a height of 452 miles. Some 15min of data were tele- metered to ground stations before the fourth stage and payload came down in the Atlantic 642 miles from Wallops. Sensors and instrumentation weighing 931b monitored such motor characteristics and performance factors as acceleration, vibration and temperatures. The ionosphere experiments, weighing about 121b, chiefly consisted of ion-electron traps and an electro- static probe to measure vertical distribution of electron density and temperatures and ion densities in the region of 150 miles to apogee and return. The X-258, manufactured by Hercules Powder Company's Allegheny Ballistics Laboratory, was developed from the X-248. In addition to its use in the Delta and Scout vehicles the X-248 has formed the standard fourth stage of NASA's Journeyman and Javelin sounding rockets. Details of the two rocket motors are as follows:— X-248 X-258 Length 57.5in 59in '•••••:;: v Diameter 18in 18in - Weight 5161b 5761b - Thrust 3,0001b 5,7001b ^ Burning time 40sec 26sec Consideration is being given to using the X-258 as the fourth stage of Javelin on a regular basis. This would increase the maximum height attainable by a 501b payload from 600 to about 700 miles. b °M °GO Spacecraft Space Technology Laboratories Inc is to uiw two additional Orbital Geophysical Observatory spacecraft or the US National Aeronautics and Space Administration. Under "existing contract STL is designing, developing, building and wstmg three OGO craft, the first of which (OGO-A) is scheduled r launch later this year. The contract for the new spacecraft,UUs D and E, is expected to total approximately $17m. The Top picture, Boeing artist's impression of a lunar orbiter spacecraft in orbit at a height of about 28 miles from the Moon's surface. The Hoeing Company is to build five lunar orbiters for NASA. They are expected to begin flight missions in 1966, taking photographs of the lunar surface and transmitting them back to Earth. Above, two McDonnell engineers act as astronauts in checking out the controls of the Gemini spacecraft at St Louis. Experiments selected for forthcoming Gemini flights are reported on the opposite page OGO series will be launched by Atlas Agenas (Cape Kennedy) and thrust-augmented Thors (Pacific Missile Range), depending on the specific missions. OGO-D will carry 20 experiments into a 600-mile polar orbit during 1965; and OGO-E will carry the same number of experiments into a highly elliptical orbit (apogee more than 90,000 miles) during 1966. Cosmos 29 was launched by the Soviet Union on April 25, according to an official Tass communique. Initial orbital elements were quoted as: period, 89.25min; apogee, 309km; perigee, 204km; inclination, 65° 4'.
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