Sep 4 2003
From The Space Library
NASA announced the completion of tests, which had taken place on 27 August at Edwards Air Force Base in California, demonstrating the possibility of reducing the impact of sonic booms. The research team showed that modifying an aircraft's shape alters the shape of its sonic boom, thus reducing the sound level. Northrop Grumman Corporation had modified the fuselage and nose of an F-5E fighter jet for the demonstration. The modified jet and a regular F-5E had each flown at Mach 1.36 from the same supersonic corridor. The two aircraft had demonstrated no difference in performance except that the modified jet's sonic boom was 33 percent less intense than that of the unmodified F-5E. Analysis and wind tunnel tests had predicted the outcome, but NASA had never before flight-tested the theory. Richard Weizman of NASA's Office of Aerospace Technology remarked that the demonstration was the culmination of 40 years of work by visionary engineers. The Defense Advanced Research Projects Agency had managed the Shaped Sonic Boom Demonstration (SSBD) program under its Quiet Supersonic Platform Initiative. NASA's LaRC and Dryden Flight Research Center (DFRC), as well as Northrop Grumman Corporation, had been partners in the SSBD program under a US$7 million cooperative agreement. (NASA, “NASA Opens New Chapter in Supersonic Flight,” news release 03-283, 4 September 2003, http://www.nasa.gov/home/hqnews/2003/sep/HQ_03283_supersonic_flight.html (accessed 28 January 2009); Irene Mona Klotz for United Press International Science News, “Test Shows Shape Sheds Sonic Boom's Bang,” 22 September 2003.
CAIB Chair Harold W. Gehman Jr. and three other Board members appeared before the U.S. House Committee on Science and Technology to discuss the CAIB's findings. Gehman testified that budgetary pressures that the U.S. Congress and the White House ultimately controlled had been partly responsible for NASA's management failures. House Committee Chair Sherwood L. Boehlert (R-NY) concurred that Congress shared some of the blame in the 1 February loss of Columbia but reiterated that NASA needed to make changes. Many of the committee's questions focused on prospective remedies for NASA's poor risk management. While agreeing that NASA had a tendency to be overly optimistic in risk assessment, Gehman and other investigators explained to the committee that, because of the age of the Shuttle fleet, risk calculations were little more than estimates. Boehlert expressed concern that NASA was rushing to meet unrealistic return-to-flight dates~NASA had proposed a March 2004 launch date~rather than studying the CAIB report carefully and taking deliberate steps toward returning the Shuttles to flight. (Paul Recer for Associated Press, “Shuttle Probe Rips White House, Congress,” Washington Post, 5 September 2003; Patty Reinert and Mark Carreau, “Don't Rush New Launch, Lawmakers Warn NASA,” Houston Chronicle, 5 September 2003.
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