Geosynchronous orbit

The Na—S system is expected to provide significant iacreases ia energy density for sateUite battery systems (69). In-house testing of Na—S cells designed to simulate midaltitude (MAO) and geosynchronous orbits (GEO) demonstrated over 6450 and over 1400 cycles, respectively. 

There is no air in space, so the satellites receive intense sunlight, unaffected by weather. In a geosynchronous orbit an SPS would be illuminated over 99% of the time. The SPS would be in Earth s shadow for a few days at the spring and fall equinoxes. This would be for a maximum of an hour and a half late at night when power demands are at their lowest. 

There are also only a limited number of available slots in geosynchronous orbit where a satellite would be able to continuously beam power to a specific receiver. In areas with plenty of sun and available land, satellites may not compete with generating solar power locally. There would be more demand for beaming solar power to locations that couldn t generate it otherwise. 

The effects of the radiation flux in space on polymer materials is now of considerable importance due to the increasing use of communications satellites. Geosynchronous orbit corresponds to the second Van Allen belt of radiation, which comprises mainly electrons and protons of high energy. 

A synchronous orbit around a celestial body is a nearly circular orbit in which the body s period of revolution equals its rotation period. This way, the same hemisphere of the satellite is always facing the object of its orbit. This orbit is called a geosynchronous orbit for the Earth where, with its sidereal rotation period of 23 hours 56 minutes 4 seconds, the geosynchronous orbit is 21,480 mi (35,800 km) above the equator on the Earth s surface. A satellite in a synchronous orbit will seem to remain fixed above the same place on the body s equator. But perturbations will cause synchronous satellites to drift away from this fixed place above the body s equa-... 

Solar Power Satellite - A solar power station investigated by NASA that entailed a satellite in geosynchronous orbit that would consist of a very large array of solar photovoltaic modules that would convert solar generated electricity to microwaves and beam them to a fixed point on the earth. 

On April 30,1999, at 12 30 EDT, a Titan IV B-32 booster equipped with a Centaur TC-14 upper stage was launched from Cape Canaveral, Florida. The mission was to place a Milstar-3 satellite into geosynchronous orbit. Milstar is a joint services satellite communications system that provides secure, jam-resistant, worldwide communications to meet wartime requirements. It was the most advanced military communications satellite system to that date. The first Milstar satellite was launched February 7,1994, and the second was launched November 5,1995. This mission was to be the third launch. 

As a result of some anomalous events, the Milstar satellite was placed in an incorrect and unusable low elliptical final orbit, as opposed to the intended geosynchronous orbit. Media interest was high because this mishap was the third straight Titan IV failure and because there had been recent failures of other commercial space launches. In addition, this accident is believed to be one of the most costly unmanned losses in the history of Cape Canaveral Launch Operations. The Milstar satellite cost about 800 milUon, and the launcher an additional 433 million. 

System Hazards (1) Ihe satellite does not reach a useful geosynchronous orbit (2) the satellite is damaged during orbit insertion maneuvers and cannot provide its intended function. 

Safety Constraint on FCS that was Violated The PCS must provide the attitude control, separation, and orientation maneuvering commands to the main engines and the RCS system necessary to attain geosynchronous orbit. 

Geostationary Earth Orbit (GEO) Geosynchronous orbit, 35,785 kilometers above the equator, so that the object in orbit appears to stay at a fixed point relative to the Earth s surface at all times. 

Clarke Belt Collective term for geosynchronous orbits, named for Arthur G. Clarke, noted science fiction author, who was the first to propose the use of satellites in these orbits for communications. 

Geosynchronous Orbit Circular orbit directly over the equator with an orbital period of precisely twenty-fom" hoiu sateDites in these orbits appear to be stationary in the sky as seen from the Earth s surface. 

Geosynchronous Orbit Orbit around Earth at a radius of 42,164 kilometers that has a period equal to the rotational period of the Earth. 

Television. For the most part, cable television employs coaxial cable to connect the head end to the subscribers premises. The system gets its signal from a satellite 22,300 miles above the Earth s surfece, in geosynchronous orbit. Television is also received through satellites, DSL, and fiber optics. 

Launched in 2010, the Solar Dynamic Observatory (SDO) was an Explorer-class mission which achieved geosynchronous orbit in order to observe the Sim (Mason and Starin, 2011). SDO required a large amount of propellant, close to half of the overall mass of the vehicle (Willis, 2012). The PMD used on this satellite was a sponge because maintaining a propellant center of mass and reducing liquid slosh were the two main objectives for PMD design. 

Geostationary Earth Orbit), 5 IGSO (Inclined Geosynchronous Orbit) and 4 MEO (Medium Earth Orbit) - BeiDou system (BDS) has formally begun to provide services to China and the surrounding areas since December 2012 (Report...2013,... 

This objective will be given most often as a minimum limit on the probability of reaching a given duration. The probability values are rarely published, but when they are, they vary from quite modest values (aroimd 60%) to much more constraining values of the order of 90%, for example, with allocation of values even higher for sub-systems and equipment. These values are assessed in relation to the associated duration, which may be only a few months for some missions in a very difficult environment, but are most commonly in the range of 5 to 7 years in low Earth orbit, and up to values of 15 to 20 years for telecommunications satellites in geosynchronous orbit for example. 

The present state of development of individual pressure vessel (IPV) nickel-hydrogen battery cells is that they are acceptable where not many cycles are required over life, i.e. 1000 cycles over 10 years of geosynchronous orbit applications, but are not acceptable in applications where many cycles are required, typically 30 000 over five years. In low earth orbit applications only 6000 to 10000 cycles at 80% depth of discharge can be achieved. 

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