Nov 17 2006
From The Space Library
The joint ESA-NASA Ulysses spacecraft commenced its third passage over the Sun’s south pole, an event that scientists expected would reveal new information about changes in the Sun and the effects of those changes on space. Carried into space in 1990 by the Space Shuttle Discovery, Ulysses was on a mission to explore the heliosphere—the region of space influenced by the Sun and its magnetic field. Data gathered during Ulysses’s orbit of the Sun, once every 6.2 years, was enabling scientists to study the Sun’s 11-year cycle of maximum and minimum solar activity. Moreover, Ulysses had accomplished 17 years of orbit, making it possible for scientists to study the Sun during its entire 22-year magnetic cycle. The spacecraft had first passed over the Sun’s south pole in 1994 and over its north pole in 1995, both passes occurring during a phase of minimum solar activity. Ulysses’s second set of polar passes, in 2000 and 2001, had occurred during a period of maximum solar activity. The spacecraft’s third passage over the Sun’s south pole was occurring during another period of minimum solar activity, but this pass would provide new data because the Sun’s magnetic field had reversed in polarity since the spacecraft’s first passage over the south pole. Ulysses is part of the Heliospheric Network, a spacecraft fleet that includes NASA’s ESA, the joint ESA-NASA Solar and Heliospheric Observatory (SOHO), and other spacecraft.
NASA, “NASA-European Spacecraft Swoops Under Sun’s Pole,” http://www.nasa.gov/vision/universe/solarsystem/ulysses-20070207.html (accessed 14 September 2010); ESA, “Ulysses Embarks on Third Set of Solar Passes,” http://www.esa.int/esaSC/SEMWPIUXJUE_index_0.html (accessed 14 September 2010).
GAO released a report stating that the U.S. Department of Defense (DOD) needed to correct its unrealistic cost estimates for its major space acquisition programs. Analyzing six of the U.S. Air Force’s ongoing space programs, GAO had found that the programs’ estimated costs had increased by US$12.2 billion, 44 percent over initial cost estimates. The report attributed this cost growth to the DOD’s practice of commencing programs before determining whether sufficient financial resources would be available to complete them. GAO suggested that this practice had developed because of pressures on the DOD to secure program funding. The report also stated that the DOD’s unrealistic cost estimates had exacerbated its problems with acquisitions for the Air Force’s programs. For example, the DOD had frequently had to move funds between programs to cover the costs of poorly performing programs. This had led to inefficiencies in meeting programs’ costs and schedules. The DOD agreed with the report’s findings and outlined specific steps it planned to take to make the Air Force’s cost estimates more accurate.
U.S. Government Accountability Office, “Space Acquisitions: DOD Needs To Take More Action To Address Unrealistic Cost Estimates of Space Systems” (report no. GAO-07-96, Washington, DC, 17 November 2006), 1–6, http://www.gao.gov/new.items/d0796.pdf (accessed 29 April 2010).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
