http://www.chron.com/cs/CDA/story.hts/special/02/wsc/1611297
Three decades after the final Apollo voyage to the lunar surface, NASA's lead visionaries are taking a fresh look at the moon as the steppingstone to deep space discovery. Under a still-formative strategy, a new Earth-orbiting habitat near the moon would become the staging site for 21st-century human and robotic missions designed to unravel some of the most compelling cosmic mysteries. Some of the questions scientists want to answer: � What are the moon's origins? � How did the solar system evolve? � Does Mars host some form of life, or did it in the past? � Do Earth-like planets circle nearby stars? � Is there intelligent life elsewhere in the universe? "We are going where scientists need humans," said NASA's Gary Martin, who chairs a group of 60 space-travel experts called the NASA Exploration Team, or NEXT, which is charged with thinking about the next step. "We are not just trying to hurry up and go. We are actually looking at when scientists need us and what they need humans to do." Strategists have yet to formulate a credible timetable and price tag for the habitat initiative and many of the missions to follow, according to Martin. But the lunar habitat could represent the next push to expand human presence in space beyond the international space station. Construction of the space station is expected to require several more years, and research operations aboard the orbiting laboratory are planned through at least 2017. Nonetheless, NASA's brainstorming will be a topic of discussion during the World Space Congress in Houston. The nine-day gathering begins today and is expected to draw 13,000 experts. Participants plan professional meetings, public forums, technical sessions and closed-door strategy sessions on the major issues facing space exploration and commerce. The NEXT team is sponsoring an exhibition at the gathering, and team members plan more than 30 presentations. Even before America's 1972 retreat from the moon, NASA began to wrestle with the issue of where to explore next with astronauts. Stifled by the high cost and inherent risk of space exploration, the long-simmering post-Apollo debate has thus far produced nothing as grand. President John F. Kennedy ignited a race to the moon in 1961 in response to a pair of impressive Cold War achievements by the former Soviet Union. Soviet launchings of the first man-made satellite, Sputnik, in 1957 and the first cosmonaut, Yuri Gagarin, in 1961, raised fears that a powerful enemy also had the upper hand in missile weaponry. Kennedy and his successor, Lyndon Johnson, rallied the country to an electrifying come-from-behind victory with NASA's Apollo program. "The questions I get asked over and over again (are), `Why did we quit? Why didn't we go on? When are we going back?' " laments Gene Cernan, who became the last person to walk on the moon as the commander of Apollo 17. "I tell people we will, but it's a generation away," said Cernan, now a 68-year-old businessman. "We are not going to Mars tomorrow, and we are not going back to the moon in the next two or three years." The crew of Apollo 17, which made the last of six moon-landing missions, returned to Earth on Dec. 19, 1972. That same year, President Richard Nixon directed NASA to begin development of the space shuttle. President Ronald Reagan approved plans for an international space station in 1984. As a post-Cold War gesture, President Bill Clinton altered the space station plans in 1993 by inviting Russia to ally with the United States, Europe, Japan and Canada in the project. The alliance in part was to reduce the threat that Russia, because of economic struggles, would be tempted to export nuclear technologies to less capable adversaries. NASA's latest planning signals an intent to embrace science and discovery as the justifications for sustained human migration into space. "What we are looking at is a step-by-step expansion of increasingly advanced robots and humans in a partnership," said NASA's Harley Thronson, the NEXT team science chief. "The Apollo program was probably one of the extraordinary voyages of discovery in all of human history. At the end of the Apollo program, though, for a variety of reasons there really was no place to go. It did not set the agency on a course for subsequent exploration," said Thronson. "What we are trying to do is learn from history and build the capability for sustained human and robotic operations, ultimately throughout the solar system." NEXT strategists are focused on a realm in space between the Earth and the moon called the "L-1" Lagrangian point. This would be the orbital site for a human outpost. A pre-eminent 18th-century French mathematician, Joseph Louis de Lagrange, discovered that there are five regions of gravitational stability between two large bodies in space. They are identified as Lagrangian points L-1 through L-5. The proposed outpost would be located at L-1, enabling it to circle 187,500 miles from Earth and 37,500 miles from the moon with minimal maneuvering. "It's a very attractive location if (NASA) decides to send advanced robots or even humans to the surface of the moon. The entire surface of the moon is accessible with moderate ease. It's an excellent staging area for deep space missions, human or robotic, and maybe for one day sending humans to Mars," said Thronson. "This is really where you learn to drive around the neighborhood and develop your capabilities." Findings announced earlier this year from NASA's Mars Odyssey, a robotic probe that has been circling Mars since last year, suggest vast amounts of water frozen beneath the arid surface. The discovery raises the prospect of biological activity and offers a critical resource for potential human activity on the Red Planet. Presently, the voyage is considered too risky for astronauts because of the one to two years required for a round trip and the dangerously high radiation levels in space. Human expeditions will be paced by new strides in advanced propulsion and radiation-shielding technologies. In the interim, NASA strategists are looking at an L-1 lunar habitat as a staging site for a powerful successor to the Hubble Space Telescope, an observatory equipped to survey the closest stars for Earth-like planets. A telescope of that type might be checked out at the habitat before being launched to an Earth-Sun Lagrangian point about 1 million miles away. Regions of the moon inaccessible to the Apollo astronauts are likely to draw new scientific scrutiny as well. "It's really a great natural laboratory, which is available right in your own back yard," said David Black, director of the Houston-based Lunar and Planetary Institute. "In addition, the moon itself remains of interest scientifically because there is a whole lot we don't understand." Astronauts will use the moon to test exploratory techniques and tools they will need on Mars, he believes. In July, the National Research Council, a government-funded think tank, urged scientists to place a high priority on a robotic mission to the Aitken Crater, a giant depression at the moon's south pole caused by a meteor. The depression is so deep it exposes all of the layers of the lunar crust, offering a detailed geological record of the moon's past. Scientists believe the moon was created when another large object in the solar system grazed the Earth early in the formation of the solar system, knocking off debris that then coalesced. Soil samples retrieved from the Aitken Crater may hold chemical signatures that would help identify the impactor, said Black. Radio astronomers might also find the moon's far side an attractive site for an observatory. On Earth, their efforts to gather and analyze radio signals from space are interfered with by television, radio, radar and even cellular telephone use. Radio astronomers scan the skies for broadcast signals from intelligent civilizations in distant star systems. They also scan deep space to trace the evolutionary course of stars and galaxies. xponent Interplanetary Maru rob _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
