Geostationary orbits

Asteroid mining has been seriously considered. A NASA design study produced a 10,000-ton mining vehicle to be assembled in orbit that would return a 500,000 ton asteroid fragment to geostationary orbit. 

At the higher altitude of geostationary orbit (GEO), at 36 000 km above the Earth, the space structure is exposed to a different loading regime. The environment to be encountered in GEO to which space systems would be exposed features ... 

As applied to space missions (a CV delivery to the geostationary orbit, cargo delivery to the Moon, Mars), different NPPs with the thrust between 5 kN and 10 kN, total time of the engine operation 1-6 h at 10-20 start-ups were put under consideration. Due to the difficulty to perform running tests of powerfiil engines, the opportunity to employ a hunch of engines for spacecrafts was considered. 

The NPPS based on the NPP technology are effective at high-altitude near-earth orbits as electric power sources. With the NPPS thrust of about 500 kN, time of delivery to the geostationary orbit will be 6-10 h. 

Geostationary satellites are positioned in a circular orbit in the Earth s equator plan. More technically, a geostationary orbit is a circular prograde orbit in the equatorial plane with an orbital period equal to 24 h (Figure 14.1). Positioning the satellite at an... 

Due to their main characteristics (fixed position over one point on the Earth), these satellites are mainly used for telecommunications hy operators that have assembled fleets covering the Earth (direct home TV broadcasting, voice and internet Intelsat, Eutelsat, Astra satellites, etc.). It is also important to remember that GEO satellites are used for Earth observation purposes (remote sensing) in addition to communication applications meteorological satellites are also positioned in geostationary orbits (Meteosat and National Oceanic and Atmospheric Administration satellites). 

Low Earth Orbits. Low earth orbit (LEO) refers to a satellite orbiting between 140 and 970 kilometers above the Earth s surfece. The periods are short, only about ninety minutes, which means that several of them are necessary to provide the type of uninterrupted communication characteristic of geostationary orbits, which have twenty-four-hour periods. Although a larger number of low earth orbits are needed, they have lower launching costs and require less energy for signal transmission because of how close to the Earth they orbit. 

Several forms of radio communications—satellites, cellular radio, and Wi-Fi— are commonly in use. Satellite communications can be used for voice, television, or data. When used for voice, satellites often result in an undesirable confusion because the time required to bounce a signal off a satellite (parked at an altitude of 22,300 miles, in geostationary orbit) is 0.125 second each way. Therefore, there is a built-in 0.25-second delay in any conversation. 

Considering an outline design as suggested by Little (2011) (see Section 19.4.1), the collected electrical energy from solar collectors supported by satellite no. 1 at geostationary orbit would be beamed to Earth by laser onto satellite no. 2 positioned some 20 kilometres above the Earth. Satellite no. 2 would support the equipment to transform the laser to microwaves which would be beamed to a ground receiver. Ideally both satellites 1 and 2 would be fabricated from a polymer/libre composite skeletal space structure to support the collectors and equipment. Figure 19.9 illustrates the components that would be required for the SBSP system. 

Inflatable and flexible continuum structure. The unit elements of the inflatable continuum structure would be stowed into a minimum volume in the cargo bay of the space transporter, launched and deployed at LEO. The various unit elements would be inflated and joined by EVA. Any equipment required would be connected at LEO and the whole would be transported to geostationary orbit. The system is described in Chapter 20, Section 20.7.4. 

PI films loaded with 15 wt. % of Si-microcapsules loaded with TMPTA monomer exposed 30 min are equivalent to 6 month exposure at the real space condition over geostationary orbit of the earth. 

A radiometer is installed in the European weather satellite METEOSAT at a geostationary orbit of 36 000 km altitude over equatorial Africa imaging the Earth s surface with a resolution of 2.5 km in order to monitor weather conditions. The camera system with an aperture of 400 mm has to resist very large temperature fluctuations during the change from direct solar irradiation to the shadow of the Earth and must also operate for many years without maintenance. 

Stentor, which was an attempt to demonstrate the use of a Saf 140 Ah lithium-ion battery system in a geostationary orbit... 

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