Nov 16 2006
From The Space Library
NASA announced the completion of the first systems requirements review (SRR) for its Constellation Program, a human spaceflight program aimed at sending astronauts to the Moon and possibly to Mars. NASA was conducting SRRs of human spacecraft systems to establish a foundation for the design, development, construction, and operation of those systems. NASA had completed its last review in August 1973 for the Space Shuttle program. The Constellation Program SRR examined the systems intended to replace the Shuttle systems, including the Orion spacecraft and the Ares I and Ares V launch rockets. The review confirmed numerous parameters of those systems, including Orion’s launch weight for lunar missions (61,000 pounds, or nearly 27,700 kilograms) and the Ares rockets’ capacity to provide sufficient thrust to launch Orion into orbit. NASA also announced that it was preparing detailed project-level reviews of the Constellation Program’s systems, scheduled for completion in early 2007. After completing those reviews, NASA would conduct another full review to reconcile information gained in the project-level reviews with the data from the first SRR.
NASA, “NASA Completes Milestone Review of Next Human Spacecraft System,” news release 06-354. 16 November 2006, http://www.nasa.gov/home/hqnews/2006/nov/HQ_06354_Constellation.html (accessed 7 July 2010).
Scientists using NASA’s HST reported research demonstrating how an enigmatic form of energy called dark energy has helped shape the universe’s structure. Unable to observe dark energy directly, scientists analyze it by measuring its effects on matter. Previous research had revealed that dark matter causes the universe to expand by counteracting the collapsing gravitational pull of matter throughout the universe. However, several properties of dark matter had remained a mystery, such as how strong it is and when it began to exert its expansive effects. Attempting to solve some of these puzzles, a team of scientists, led by Adam G. Reiss of the Space Telescope Science Institute, had examined HST data on the luminosity distances of the farthest known supernovae—a type of ancient exploding star—to measure the universe’s rate of expansion. The scientists found that dark energy had begun to accelerate the universe’s expansion as long ago as 10 billion years, and that the expansive force of dark energy, although weak, had been sufficiently consistent to counteract gravity. In addition, the research supported Albert Einstein’s theory of the existence of a “cosmological constant” that works against gravity to create equilibrium in the universe.
Adam G. Riess et al., “New Hubble Space Telescope Discoveries of Type Ia Supenovae at z = 1: Narrowing Constraints on the Early Behavior of Dark Energy,” Astrophysical Journal 659, no. 1 (10 April 2007): 98–121, http://iopscience.iop.org/0004-637X/659/1/98 (DOI 10.1086/510378; accessed 29 April 2010); Dennis Overbye, “9 Billion-Year-Old ‘Dark Energy’ Reported,” New York Times, 17 November 2006.
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