The melting of the supergiant iceberg A-68 had a huge impact on the ocean around South Georgia, in sub-Antarctica, and significantly changed the Southern Ocean's temperature and saltiness, with potentially major consequences ...
Earth Sciences
14 hours ago
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19
Artisanal and small-scale gold mining is a lifeline for many who live in Madre de Dios, a region in southeastern Peru, where poverty is high and jobs are scarce. But the economic development in this part of the Amazon basin ...
Earth Sciences
Sep 21, 2023
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5
Accurate estimates and forecasts of crop area and yield play an important role in guiding policy decisions related to food security, especially in light of the growing impacts of climate change. IIASA researchers and colleagues ...
Biotechnology
Sep 21, 2023
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27
People experiencing a high degree of social vulnerability are also more exposed to wildfires in Oregon and Washington as wildfire risk increases, a new study shows.
Environment
Sep 20, 2023
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People have been using fire for millennia. It is a vital part of many ecosystems and cultures. Yet human activities in the current era, sometimes called the "Anthropocene," are reshaping patterns of fire across the planet.
Earth Sciences
Sep 15, 2023
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Following the devastating earthquake that struck Morocco on 8 September, satellite data have been made available through the International Charter "Space and Major Disasters" to help emergency response teams on the ground.
Planetary Sciences
Sep 14, 2023
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4
Following the calving of the A-81 iceberg at the end of January 2023, the Brunt Ice Shelf is moving faster than before. It is currently moving approximately 4 meters a day towards the sea, whereas before the calving it moved ...
Earth Sciences
Sep 13, 2023
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38
Most people consider climate change to consist only of the warming of the atmosphere, the consequences of which primarily affect land regions. However, this is a human-centered view and does not go far enough.
Earth Sciences
Sep 12, 2023
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106
As the calibration and validation of the various elements of the spacecraft and ground segment progresses, data captured by the two main instruments on board MTG-I1, the Flexible Combined Imager (FCI) and the Lightning Imager ...
Planetary Sciences
Sep 11, 2023
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15
All countries have a variety of water resources—some are on the surface, like rivers, and some are beneath the ground. This groundwater provides almost 50% of all global domestic use and 43% of all the water used for agriculture.
Earth Sciences
Sep 4, 2023
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11
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
