Word: orbital
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...Moon come to be? Prevailing wisdom has it that 4.5 billion years ago, a collision between the Earth and an object larger than Mars tossed immense quantities of vapor and debris into orbit around our planet. Eventually, the gas and rock formed a disk of dust which cooled and clumped together to form the moon. That theory received a major boost Thursday thanks to a study published in the journal Nature. Using computer simulations, University of Colorado scientists showed how a single moon can grow in this fashion. The researchers conducted 27 simulations which tracked up to 2,700 objects...
...Planet was a signal accomplishment for Surveyor. Launching a spacecraft from Earth to Mars, says NASA, is like firing a baseball from California to New York and hitting a particular window in the Empire State Building. Having managed this navigational tour de force, Surveyor then had to enter Mars orbit--a maneuver that carried its own risks...
Before it could slow itself sufficiently to be captured by Mars' gravity, the ship had to pressurize its fuel lines and fire its retrorockets. The last time NASA tried to orbit Mars was in 1993, and that mission ended during pressurization when a fuel line hemorrhaged, sending the billion-dollar Mars Observer probe spinning into the void. Last Tuesday was Surveyor's turn to prime its lines, and despite some well-bitten nails in Mission Control, this time things went perfectly. "To see this event pass successfully is a great relief," said project manager Glenn Cunningham after the pressurization...
...time being, Surveyor won't do much at Mars but orbit. The ship's path around the planet is elliptical, with a low point of 155 miles and a high point of 35,000. Each time Surveyor barnstorms Mars on its close approach, however, it drags a solar panel through the atmosphere in a process called aerobraking. A few months of this cosmic paddling will refine the orbit so that by early next year, the ship will inscribe a near perfect 235-mile circle. Then it will switch on its instruments...
...station and place them squarely on the shoulders of one person. Putting a space station thousands of miles above the earth is a great scientific achievement. Just because Tsibliyev is a Russian, he is ridiculed. Don't forget that Mir is the only manned space station to remain in orbit for 11 years. PAREEN SHAH Sterling Heights, Mich...