A group of researchers have reported how much peatland there is in the world. Peatlands can store carbon (C) and help regulate the climate. But peatland degradation is releasing carbon into the atmosphere. To conserve peatlands ...
Earth Sciences
15 hours ago
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For decades, scientists studying a key climate phenomenon have been grappling with contradictory data that have threated to undermine confidence in the reliability of climate models overall. A new study, published today in ...
Earth Sciences
Jun 24, 2019
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Harmful algal blooms can cause big problems in coastal areas and lakes across the United States. When toxin-containing aquatic organisms multiply and form a bloom, it can sicken people and pets, contaminate drinking water, ...
Environment
Jun 21, 2019
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Water is so commonplace that we often take it for granted. But too much—or too little of it—makes headlines.
Earth Sciences
Jun 12, 2019
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When the Fluvial Dynamics and Hydrology research group at the University of Cordoba, led by Professor María José Polo, got to the Spanish Sierra Nevada in 2002, there were no weather stations above the height of 1,200 meters, ...
Earth Sciences
Jun 10, 2019
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Most people get a health boost from exercise. But for those with heart disease or a lung condition such as asthma, exercising during periods of high urban air pollution can exacerbate rather than improve their condition.
Space Exploration
Jun 10, 2019
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7
ESA's Planck satellite has found no new evidence for the puzzling cosmic anomalies that appeared in its temperature map of the Universe. The latest study does not rule out the potential relevance of the anomalies but they ...
Astronomy
Jun 06, 2019
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992
Climate change is bringing more water to people's doorsteps, devastating communities. Entire towns are moving to escape rising waters. But how do towns address these growing threats and still retain their sense of community? ...
Environment
Jun 06, 2019
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5
New research by UMBC's Glenn Wolfe and collaborators is shaping how scientists understand the fate of methane, a potent greenhouse gas, in Earth's atmosphere.
Earth Sciences
Jun 03, 2019
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163
NASA's Aqua satellite used infrared light to analyze the strength of storms in the developing low pressure area designated as System 91L is it moved through the Gulf of Campeche just north of Mexico's Yucatan Peninsula.
Environment
Jun 03, 2019
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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
