Bøger af Michael Meltzer

Each time a space vehicle visits another world it runs the risk of forever changing that extraterrestrial environment. We are surrounded on Earth by a mélange of different microorganisms, and if some of these hitchhike onboard a space mission, they could contaminate and start colonies on a different planet. Such an occurrence would irrevocably alter the nature of that world, compromise all future scientific exploration of the body, and possibly damage any extant life on it. And by inadvertently carrying exotic organisms back to Earth on our spacecraft, we risk the release of biohazardous materials into our own ecosystem. Such concerns were recognized by scientists even before the 1957 launch of Sputnik. This book presents the history of planetary protection by tracing the responses to the above concerns on NASA's missions to the Moon, Mars, Venus, Jupiter, Saturn, and many smaller bodies of our solar system. The book relates the extensive efforts put forth by NASA to plan operations and prepare space vehicles that return exemplary science without contaminating the biospheres of other worlds or our own. As Cassie Conley, NASA's Planetary Protection Officer, has said, "The public can be proud of the way that NASA has responded to planetary protection concerns, with its efforts to act responsibly, communicate openly, and address effectively the potential for contamination." Humans have a powerful urge to explore the unknown, but to protect irreplaceable environments, NASA has committed to conducting space exploration in a manner that is protective of the bodies visited, as well as of our own planet.

The Galileo mission to Jupiter explored an exciting new frontier, had a major impact on planetary science, and provided invaluable lessons for the design of spacecraft. This mission amassed so many scientific firsts and key discoveries that it can truly be called one of the most impressive feats of exploration of the 20th century. In the words of John Casani, the original project manager of the mission, "Galileo was a way of demonstrating . . . just what U.S. technology was capable of doing." An engineer on the Galileo team expressed more personal sentiments when she said, "I had never been a part of something with such great scope . . . . To know that the whole world was watching and hoping with us that this would work. We were doing something for all mankind." When Galileo lifted off from Kennedy Space Center on 18 October 1989, it began an interplanetary voyage that took it to Venus, to two asteroids, back to Earth, and finally on to Jupiter. The craft's instruments studied Jupiter's enormous magnetosphere and its belts of intense radiation. The spacecraft also sent off a planetary probe that accomplished the most difficult atmospheric entry ever attempted. After this, the craft spent years visiting Jupiter's moons and delving into their structures and properties. This book attempts to convey the creativity, leadership, and vision that were necessary for the mission's success. It is a book about dedicated people and their scientific and engineering achievements. The Galileo mission faced many significant problems. Some of the most brilliant accomplishments and "work-arounds" of the Galileo staff occurred precisely when these challenges arose. Throughout the mission, engineers and scientists found ways to keep the spacecraft operational from a distance of nearly half a billion miles, enabling one of the most impressive voyages of scientific discovery.

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The Cassini-Huygens spacecraft design evolved from other deep space efforts, most notably the Galileo mission to Jupiter, enabling the voluminous, paradigm-shifting scientific data collected by the spacecraft.