Indian Satellites and NavIC: Series, Firsts and MCQs

The correct answer is B, Aryabhata in 1975. It was launched on 19 April 1975 by a Soviet launch vehicle, since India had no vehicle of its own at the time, and it carried experiments in X-ray astronomy, solar physics and the ionosphere. It was named after the ancient Indian mathematician and astronomer.

Option A, Rohini of 1980, holds a different record: it was the first satellite placed in orbit by an Indian launch vehicle, SLV-3, on 18 July 1980, and candidates who mix the two records choose it. Option C, Bhaskara-1 of 1979, was the first experimental earth observation satellite. Option D, APPLE of 1981, was the first experimental communication satellite and went up on the European Ariane rocket. The clean chain to memorise is 1975 first satellite, 1979 first earth observation, 1980 first Indian launch, 1981 first communication satellite.

The correct answer is A, Navigation with Indian Constellation. The name was given in 2016 to the Indian Regional Navigation Satellite System, IRNSS, when the seventh satellite of the constellation was placed in orbit, and the word navik also carries the sense of a sailor or navigator, which is why it was chosen.

Options B, C and D are invented expansions of the kind an examiner adds to see whether the candidate has read the term or only heard it. The two facts that go with the full form are that NavIC is the Indian system built so that the country does not depend on another nation's signals, and that it is a regional system covering India and a belt of about 1,500 km beyond its boundary rather than the whole earth. Keep IRNSS and NavIC as the old and new names of one system.

The correct answer is B, seven. The system was designed as a constellation of seven satellites, three of them in geostationary orbit and four in geosynchronous orbits inclined to the equatorial plane, a small number being enough because the service area is regional and not global. IRNSS-1G, launched in April 2016, completed the seven.

Option A, four, is the number of inclined satellites alone and is the trap for a candidate who remembers the split but not the total. Option D, twenty-four, is roughly the size of a global constellation such as GPS, which needs satellites spread over the whole earth. Option C, nine, matches no system. Remember the split as three plus four, and remember that the second-generation NVS satellites are replacing the first-generation ones as they age.

The correct answer is B, Kalpana-1. Launched in 2002 as METSAT, it was the first Indian satellite built only for weather work, and it was renamed Kalpana-1 in memory of Kalpana Chawla, the India-born astronaut who died in the Columbia accident of 2003. Its instruments watched cloud cover, water vapour and sea surface temperature for cyclone warning.

Option A, INSAT-1B of 1983, carried meteorological instruments but was primarily a communication satellite, which is the distinction the word exclusively tests. Option C, Bhaskara-2, belonged to the early experimental earth observation series of 1979 and 1981. Option D, Oceansat-1 of 1999, studied the sea, its colour and winds over it, so it is an ocean rather than a weather satellite. The later dedicated weather satellites in this line are the INSAT-3D series.

The correct answer is B, a dedicated multi-wavelength space observatory. Astrosat was launched on 28 September 2015 by a PSLV and carries instruments that observe the same cosmic source in the ultraviolet, the visible and the X-ray bands at the same time, which is what multi-wavelength means and what makes the mission unusual among space telescopes of its size.

Option A describes the RISAT series, which images the ground through cloud and at night using radar. Option C describes the IRNSS and NVS satellites of the NavIC constellation. Option D describes EDUSAT of 2004, the first Indian satellite meant only for education and classroom broadcasting. Two other science missions belong in the same list of firsts: Aditya-L1 of 2023, the first solar observatory, and XPoSat of 2024, which studies the polarisation of cosmic X-rays.

The correct answer is B, the first Lagrange point, L1, of the sun and earth system, about 1.5 million kilometres from the earth towards the sun. A Lagrange point is a place where the gravitational pulls of the two bodies and the orbital motion balance, so a spacecraft can stay there with very little fuel, and from L1 the sun can be watched continuously without eclipse or occultation. Aditya-L1 was launched on 2 September 2023 by a PSLV.

Option A, L2, lies on the far side of the earth from the sun and is used by telescopes that look away from the sun. Option C is wrong because the spacecraft orbits a point in the sun-earth system, not the sun itself. Option D would put it in earth orbit, where the earth would block the view for part of every day, which is precisely what the mission had to avoid. Remember the pair: L1 for solar watching, 1.5 million km.

The correct answer is B, IRS-1A, launched in 1988, which began the Indian Remote Sensing series and was the first such satellite whose data was used routinely for crop assessment, forest mapping, water resources and land use rather than only for experiment.

Option A, Bhaskara-1 of 1979, was the first experimental earth observation satellite, and the word experimental is what separates it from IRS-1A, so read the stem carefully. Option C, Cartosat-1 of 2005, gave high resolution imagery for mapping and came much later in the same programme. Option D, RISAT-1 of 2012, was the first indigenous radar imaging satellite, able to see through cloud and work at night. The order to keep is Bhaskara experimental, IRS operational, Cartosat mapping, RISAT radar, and note that the data from this family is received and distributed by the National Remote Sensing Centre at Hyderabad.

The correct answer is C, China. BeiDou is the Chinese global navigation satellite system, built in phases and now offering worldwide coverage, and the name is the Chinese term for the constellation of the Big Dipper.

Option A, Japan, operates QZSS, the Quasi-Zenith Satellite System, which like NavIC is regional rather than global. Option B, Russia, operates GLONASS, the successor of the Soviet system of the same design. Option D, the European Union, operates Galileo, a civil global system deliberately kept outside military control. Add GPS of the United States and India's NavIC and the list is complete, with only NavIC and QZSS being regional. Examiners ask this as a simple pair matching question, so learn the five names with their owners, and remember that the general term for all of them is a global navigation satellite system.

The correct answer is B, the Airports Authority of India. GAGAN stands for GPS Aided GEO Augmented Navigation and was developed by ISRO together with the Airports Authority so that civil aircraft in Indian airspace get position information accurate and reliable enough for approach and landing. It does not have navigation satellites of its own; it broadcasts corrections that improve the signals already available.

Option A, the Indian Air Force, uses satellite navigation but is not the partner in this civil aviation project. Option C, the India Meteorological Department, works on weather and uses satellite data of a different kind. Option D, the Directorate General of Shipping, deals with merchant shipping, and marine users are served by NavIC rather than by GAGAN. The distinction worth carrying into the hall is that NavIC provides signals while GAGAN only corrects them.

The correct answer is C, the European Ariane rocket. The full name of the satellite, Ariane Passenger Payload Experiment, contains the answer, since it flew as a passenger on an Ariane launch in 1981 to test the building of a geostationary communication satellite in India. India then had no vehicle able to reach a geostationary transfer orbit.

Option A, SLV-3, could place only about 40 kg in a low earth orbit and could never have carried APPLE to the height a communication satellite needs. Option B, a Soviet vehicle, had launched Aryabhata in 1975 and Bhaskara in 1979, so it is a reasonable guess but the wrong one here. Option D, the Space Shuttle, carried the later INSAT-1B in 1983, which is a separate fact often asked alongside. The bullock cart photograph of APPLE at the test site is from this programme.