Cartosat: A series of Earth observation spacecraft (1, 2, 2A and 2B) that ISRO has launched for cartographic or mapping uses.

Footprint: coverage of a satellite over a geography/country

Frequency bands (L, S, C, Ku, X, Ka, etc ): Portions or “bands” of the electromagnetic spectrum; each band enables different uses

Gagan: The Indian top-up to the United States’ Global Positioning System.

An ISRO-Airports Authority of India venture, it improves locational or GPS readings for airline pilots flying within the country; acronym for “GPS Aided Geo-Augmented Navigation”

GSLV: ISRO has developed the Geostationary Satellite Launch Vehicle to lift its communication satellites (weighing two tonnes) to a distance of 36,000 km from earth.

After a mixed bag of seven launches since 2001, four of them failures, ISRO is perfecting this rocket and also coming out with a four-tonne version, the GSLV Mk III. PSLV, the smaller rocket for lifting IRSs into lower orbits, is working well and has done 29 launches.

Insat (or GSAT): ISRO’s fleet of communication satellites, known by their prior registration with the International Telecommunication Union; normally two to three tonnes and orbit at a distance of 36,000 km from the ground.

IRS: Indian Remote Sensing satellite, normally weighs less than 1 tonne and orbits at 600-900 km from earth

TES: Technology Experiment Satellite, launched in 2001 for strategic high-resolution observation and imaging of earth

Transponder: the portion on a satellite that keeps it connected with earth while in orbit; receives and re-sends communication to ground

VSAT: “Very Small Aperture Terminal” or system that enables communications of large corporate or public sector entities