Types of Satellites and Orbits

Definition

Artificial objects placed in orbit around the Earth, classified by their purpose and by the altitude and shape of the orbit they occupy.

Key points

• A geostationary orbit lies about 36,000 kilometres above the equator; a satellite there circles in 24 hours and so appears fixed over one point, ideal for communication, broadcasting, and weather satellites (such as India's INSAT and GSAT series).
• A polar (Sun-synchronous) orbit is a low Earth orbit, a few hundred kilometres up, passing near both poles so the satellite scans the whole Earth strip by strip; it is used for remote sensing, mapping, and reconnaissance (India's IRS and Cartosat series).
• Low Earth orbit (LEO), roughly 200 to 2,000 kilometres, is used by the International Space Station and many imaging and constellation satellites; medium Earth orbit (MEO) hosts navigation satellites such as GPS.
• Navigation systems use dedicated constellations: the United States GPS, Russia's GLONASS, the EU's Galileo, China's BeiDou, and India's regional NavIC (IRNSS).
• Communication satellites need geostationary orbit so dish antennas can point at a fixed spot, while observation satellites need lower polar orbits for sharper, repeated coverage.

Why it matters for CAPF

Geostationary versus polar orbits, the 36,000 kilometre figure, the use of communication versus remote-sensing satellites, and the major navigation constellations including NavIC are recurring space-technology facts with surveillance and border-management relevance.

Common confusion

A geostationary satellite is at high altitude (36,000 kilometres) and appears stationary, while remote-sensing satellites are in low polar orbits and keep moving; do not place imaging satellites in geostationary orbit. GPS is American and NavIC is Indian; they are separate systems.

Related concepts

concept gps and navic, concept ballistic vs cruise missiles, concept electromagnetic spectrum

Parent note

space and defence technology