Magellan missionRadar sensing and image interpretation Essay

Magellan missionRadar sensing and image interpretation - Essay Example The Mission was named after Ferdinand Magellan, a Portuguese-born explorer in the sixteenth century, who led an expedition that first circumnavigated the Earth. The earlier radar missions to Venus provided planetary scientist a global map of the surface of the planet and were very valuable in understanding the geological structure of the planet. However it further revealed a need for "global radar data coverage" of the planet's surface in "orders-of magnitude higher resolution" (Ford 1). This need facilitated and provided motivation to determine the design and objectives of the Magellan mission. The main purposes of the Magellan Mission were to create a global radar map of the surface of Venus at higher resolution using the synthetic aperture radar (SAR) and to determine the topographic relief of the planet. The end product of these four objectives shall be the classification of geographic and tectonic features of the surface like mountains, ridges, valleys, hills, and planes. Impact processes, lava flows, and other chemical processes will be explained and the internal density distribution of the planet will be modeled. The spacecraft design was economical and simple in relation to other spacecraft missions. In fact, the key components of the spacecraft were acquired from the spare hardware from other space programs including Voyager, Galileo, Viking, and Mariner. The spacecraft was 6.4 m long and with a mass of 3,449 kilograms. Included in the spacecraft were a single radar sensor, a large 3.7-m diameter parabolic High-Gain Antenna dish used for communication with Earth and a science instrument for radar imaging, solar panels about 9.2 m across to collect solar energy for charging the spacecraft's nickel-cadmium batteries and to power the spacecraft, three orthogonal reaction wheels used for pointing control, monopropellant hydrazine thruster system used to make adjustments of large scale orbital corrections. Subsystems included a medium-gain antenna, star scanner, on-board computer, coherent X- and S- band radio subsystem used for communication and gravity field experiments, and two tape recorders. Fig. 1. Labeled drawing of Magellan Spacecraft Key features of the Magellan spacecraft. Shown here are the different hardware and electronic subsystems of the spacecraft. (NASA) The Magellan spacecraft in the payload bay of the Space Shuttle Atlantis before its scheduled launch (Magellan Probe). Fig. 2. Magellan Spacecraft The Magellan Radar Sensor The radar sensor is a single science instrument in the spacecraft capable of acquiring data in three different modes or functions: SAR imaging mode,

The history of computer crimes Term Paper Example | Topics and Well Written Essays - 1250 words

The history of computer crimes - Term Paper Example In 1969, a student riot in Canadian school building resulted to damages totaling around $2 million. The students were protesting against a racist professor when their riots resulted to a fire breaking out and destroying computers and other university property. 97 students were arrested in the incident (Concordia University, 2008). In 1970, several computer crimes were reported. A bomb at the University of Wisconsin resulted to $16 million worth of computer damage; a Molotov cocktail bomb caused $1 million damage to the Fresno State College; and students at the New York University wanting to free a jailed Black Panther damaged computers by placing fire-bombs on top of the Atomic Energy Commission (Kabay, 2008). Computers were often damaged during the 1970s in order to make a statement; antiwar protests in Australia resulted to the shooting of an American firm’s computers; terrorists poured gasoline on a university’s computers and burned them; and a peace activist destroy ed a computer at the Vanderburg Air Base in California as a sign of protest against American military policies (Kabay, 2008). From 1970 to 1972, Albert the Saboteur created problems for the National Farmers Union Service Corporation of Denver. Albert enjoyed having the repair crews over every time the computer crashed. As a result, he deliberately caused the computers to crash about 50 times in the span of 2 years. He lived an isolated life as a night shift operator. He finally got company and human interaction because of the computer crashes, and he could not help but cause one crash after another just to have company (Kabay, 1996). In 1970, Jerry Schneider posed as a PT&T employee and ordered $30,000 worth of equipment from PT&T. He retrieved PT&T computer printouts from dumpsters. He was later able to collect detailed information on various procedures in the company and as a result was able to successfully steal $1 million worth of equipment from