Thermosphere gas and the ionospheric plasma. The International Space Station orbits the Earth within the middle of the thermosphere, between . It is convenient to separate the atmospheric regions according to the two temperature minima at about 12 km altitude (the tropopause) and at about 85 km (the mesopause) (Figure 1). The thermosphere (or the upper atmosphere) is the height region above 85 km, while the region between the tropopause and the mesopause is the middle atmosphere (stratosphere and mesosphere) where absorption of solar UV radiation generates the temperature maximum near 45 km altitude and causes the ozone layer. The density
S band companies are allowed two years to start providing pan-European MSS services for 18 years. Allocated frequencies are 1.98 to 2.01 GHz for Earth to space communications, and from 2.17 to 2.2 GHz for space to Earth communications. Eutelsat W2A satellite launched in April, 2009 and located at 10° East is currently the unique satellite in Europe operating on S band frequencies. In some countries, S band is used for Direct-to-Home satellite television (unlike similar services in most countries, which use K band). The frequency typically allocated for this service is 2.5 to 2.7 GHz (LOF 1.570 GHz). IndoStar-1 was the