Posts Tagged ‘satellite’

NASA Observatories Take An Unprecedented Look Into Superstar Eta Carinae

January 8, 2015 Leave a comment

Image Credit:  NASA, ESA, and the Hubble SM4 ERO Team

Image Credit:
NASA, ESA, and the Hubble SM4 ERO Team

Eta Carinae, the most luminous and massive stellar system within 10,000 light-years of Earth, is known for its surprising behavior, erupting twice in the 19th century for reasons scientists still don’t understand. A long-term study led by astronomers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, used NASA satellites, ground-based telescopes and theoretical modeling to produce the most comprehensive picture of Eta Carinae to date. New findings include Hubble Space Telescope images that show decade-old shells of ionized gas racing away from the largest star at a million miles an hour, and new 3-D models that reveal never-before-seen features of the stars’ interactions.

“We are coming to understand the present state and complex environment of this remarkable object, but we have a long way to go to explain Eta Carinae’s past eruptions or to predict its future behavior,” said Goddard astrophysicist Ted Gull, who coordinates a research group that has monitored the star for more than a decade.

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ROSAT Satellite Set to Re-enter Earth’s Atmosphere

October 17, 2011 Leave a comment

During its mission, the ROentgen SATellite (ROSAT) performed its observations in an elliptical orbit at distances of between 585 and 565 kilometres above the surface of the Earth. Since its decommissioning, atmospheric drag has caused the satellite to lose altitude. In June 2011, it was at a distance of only about 327 kilometres above the ground. Due to the fact that ROSAT does not have a propulsion system on board, it was not possible to manoeuvre the satellite to perform a controlled re-entry at the end of its mission in 1999. When the spacecraft re-enters the atmosphere at a speed of approximately 28,000 kilometres per hour, the X-ray observatory will break up into fragments, some of which will burn up by the extreme heat. The latest studies reveal that it is possible that up to 30 individual pieces weighing a total of 1.7 tons may reach the surface of the Earth. The largest single fragment will probably be the telescope’s mirror, which is very heat resistant and may weigh up to 1.7 tons.

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Bus-sized satellite to re-enter Earth’s atmosphere this week

September 20, 2011 Leave a comment

UARS, a NASA satellite the size of a small bus, will re-enter Earth’s atmosphere later this week producing a brilliant fireball somewhere over our planet.  Best estimates place the re-entry time during the late hours of Sept. 23rd over a still-unknown region of Earth. Observers of the rapidly-decaying satellite say it is tumbling and flashing, sometimes almost as brightly as Venus.  Video images featured on today’s edition of show how the doomed satellite looks through a backyard telescope.

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NASA Announces Media Teleconference About Satellite Re-Entry

September 7, 2011 Leave a comment

NASA will host a media teleconference at 11 a.m. EDT on Friday, Sept. 9, to discuss the anticipated re-entry of the agency’s decommissioned Upper Atmosphere Research Satellite (UARS). Re-entry is expected late this month or early October.

The teleconference participants are:

— Paul Hertz, chief scientist, NASA’s Science Mission Directorate, Washington
— Nick Johnson, chief scientist, NASA’s Orbital Debris Program, Johnson Space Center, Houston
— U.S. Air Force Maj. Michael W. Duncan, deputy chief, space situational awareness, U.S. Strategic Command, Vandenberg Air Force Base, Calif.

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