In 2010s, it managed to launch most of its geosynchronous/geostationary satellites successfully on its own. The Inmarsat I-5 satellites provide global coverage using four geostationary satellites. Satellites in geostationary orbit must all occupy a single ring above the equator. Satellite phones connect directly to a constellation of either geostationary or low-Earth-orbit satellites. PSLV can also launch small satellites into geostationary transfer orbit (GTO). The system will consist of six satellites in geostationary orbits. The NMT system communicates with satellites in geostationary orbit via the Ka band. Beacons are also used in both geostationary and inclined-orbit satellites. Today there are hundreds of geostationary satellites providing remote sensing and communications. Technologies to launch geostationary satellites arrived only in 2000s. Capability to launch geostationary satellites will arrive in next decade. The bearing for geostationary satellites is constant. Its payload deliverable to a geostationary orbit is 2 tons. ISRO has also launched a set of experimental geostationary satellites known as the GSAT series. This is in contrast to the geostationary orbit, where satellites are always from the earth.