When a block of ice the size of Houston, Texas, broke off from East Antarctica's Amery Ice Shelf in 2019, scientists had anticipated the calving event, but not exactly where it would happen. Now, satellite data can help scientists ...
Earth Sciences
17 hours ago
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8
For the first time, scientists, using satellite data from the Copernicus Sentinel missions, are now able to detect individual methane plumes leaking from natural gas pipelines around the globe.
Environment
20 hours ago
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8
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Environment
Mar 01, 2021
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25
Climate change has made Europe's forests more vulnerable to hazards like fires, insect outbreaks, windthrows, or a combination of these three, according to a new JRC study.
Environment
Feb 24, 2021
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You might not like mosquitoes, but they like you, says Utah State University biologist Norah Saarman. And where you lead, they will follow.
Ecology
Feb 22, 2021
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54
As most of us learned in school, plants use sunlight to synthesize carbon dioxide (CO2) and water into carbohydrates in a process called photosynthesis. But nature's "factories" don't just provide us with food—they also ...
Earth Sciences
Feb 16, 2021
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206
In early 2019, all eyes were fixed on the Brunt Ice Shelf in Antarctica, where a massive iceberg, around the size of Greater London, appeared poised to break off. Almost two years later, the berg is desperately clinging on, ...
Earth Sciences
Feb 12, 2021
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33
Microscopic, and sometimes larger, particles of soot, smoke and dust that spew out of gas-guzzling factories, ships, cars and aircraft are responsible for 18% of total global deaths in 2018—that equals more than 8 million ...
Environment
Feb 11, 2021
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14
Deforestation has converted swaths of land in the southern Amazon region from rainforest to farmland. The uses of the deforested land are diverse, and activities can range from small-scale farming in rural settlements to ...
Earth Sciences
Feb 09, 2021
1
206
Fossil fuel pollution caused more than eight million premature deaths in 2018, accounting for nearly 20 percent of adult mortality worldwide, researchers reported Tuesday.
Environment
Feb 09, 2021
8
467
The Satellite Data System (SDS) is a system of United States military communications satellites. At least three generations have been used: SDS-1 from 1976 to 1987; SDS-2 from 1989 to 1996; SDS-3 from 1998 to the present. SDS satellites have a highly elliptical orbit, going from about 300 kilometers at perigee to roughly 39,000 km at apogee in order to allow communications with polar stations that cannot contact geosynchronous satellites. The high apogee meant that the polar regions were visible for long amounts of time, and only two satellites were required in order to achieve constant communications ability. The SDS satellites were constructed by Hughes Aircraft.
The primary purpose of the SDS satellites is to relay imagery from low-flying reconnaissance satellites to ground stations in the United States.
Each SDS-1 satellite had 12 channels available for ultra-high frequency communication. They were cylindrical in shape, roughly 25 feet (7.6 m) long. 980 watts of electrical power were available from solar panels and batteries. The SDS-1 had a mass of 1385 pounds (630 kilograms) and was launched on Titan-3B rockets. The SDS-1 satellites had similar orbits to the Air Force's Jumpseat ELINT satellites.
The SDS-2 is significantly more massive at 5150 pounds (2335 kg), with three separate communication dishes, including one for a K band downlink. Two dishes are 15 feet (4.5 meters) in diameter, while the third is 6.6 feet (2 m) in diameter. The solar arrays generate 1238 watts of power. It is believed that the Space Shuttle has been used to launch several satellites, possibly on missions STS-28, STS-38, and STS-53. Other launches have used the Titan-4 rocket.
Quasar is the rumored code name for the communications satellite.
A recent Quasar may have been launched into a high-apogee orbit from Cape Canaveral on August 31, 2004 by an Atlas 2AS rocket.
This text uses material from Wikipedia, licensed under CC BY-SA
