Which of the following is ISRO's smallest launch vehicle, designed for launching small satellites on demand?

The correct answer is C, LVM3. Chandrayaan-3 weighed close to 3,900 kg at lift-off, far beyond the reach of any lighter Indian rocket, so it flew on LVM3, the vehicle earlier named GSLV Mk III. The same vehicle had launched Chandrayaan-2 in July 2019.

Option A, PSLV-XL, carried Chandrayaan-1 in 2008 and the Mars Orbiter Mission in 2013, both far lighter spacecraft, and is the distractor most candidates fall for. Option B, GSLV Mk II, lifts about 2,250 kg to a transfer orbit, which is not enough for a lunar lander of this mass. Option D, SSLV, is built for satellites of a few hundred kilograms and could not carry a fraction of the payload. Remember the split: the two Chandrayaan missions with landers went on LVM3, while the orbiter-only Chandrayaan-1 and the Mars mission went on PSLV.

The correct answer is B, SLV-3 carrying Rohini RS-1. On 18 July 1980 the four-stage, all-solid SLV-3 placed the small Rohini RS-1 satellite in a low earth orbit from Sriharikota, and India became the sixth nation able to launch its own satellite. A. P. J. Abdul Kalam was the project director of the vehicle.

Option A names the Augmented Satellite Launch Vehicle, which came later and carried the SROSS series; its first two flights failed. Option C is wrong on both counts, because the PSLV first flew in 1993 and IRS-1A of 1988 was launched by a Soviet rocket. Option D pairs the right vehicle with the wrong satellite: Aryabhata, India's first satellite, was launched in 1975 by a Soviet launcher from Kapustin Yar, five years before India had a vehicle of its own. Keep 1975 for the first satellite and 1980 for the first Indian launch.

The correct answer is C, four. The PSLV is unusual in alternating propellants between its stages: the first and third stages burn solid propellant and the second and fourth burn liquid propellant. The liquid fourth stage can be restarted and throttled, which is what lets the vehicle drop satellites into more than one orbit on the same flight.

Option B, three, is the number of stages in GSLV Mk II and in LVM3, and is the answer candidates give when they mix the vehicles up. Option A, two, matches no Indian orbital vehicle. Option D, five, is closer to the Augmented Satellite Launch Vehicle, which is counted as a five-stage rocket because of its strap-on boosters. Note that the six strap-on motors on the larger PSLV versions are not counted as a separate stage, since they burn alongside the first stage.

The correct answer is C, the third stage. The GSLV has three stages: a solid core first stage with four liquid strap-on motors, a liquid second stage using a Vikas engine, and a cryogenic upper stage that burns liquid hydrogen with liquid oxygen. A cryogenic stage is placed on top because its very high efficiency matters most once the vehicle is above the thick air and needs the last, largest gain in speed.

Option A is wrong because a cryogenic engine cannot give the heavy thrust needed at lift-off, which is why solid motors do that work. Option B is the liquid Vikas stage, which uses propellants that are liquids at ordinary temperatures and is therefore not cryogenic. Option D does not exist on this vehicle, as the GSLV has only three stages; a fourth stage belongs to the PSLV, and that fourth stage is liquid, not cryogenic.

The correct answer is B, the PSLV. Chandrayaan-1 went up on PSLV-C11 in October 2008 and the Mars Orbiter Mission on PSLV-C25 in November 2013, both in the extended PSLV-XL configuration with six long strap-on motors. Both spacecraft were light enough for the PSLV to place them in a high ellipse from which their own engines raised them towards the moon and Mars.

Option A, GSLV Mk III, now called LVM3, was not yet operational in 2008 and was used later for Chandrayaan-2 and Chandrayaan-3. Option C, SLV-3, could lift only about 40 kg and was retired in the early 1980s. Option D, GSLV Mk II, is meant for communication satellites bound for geostationary orbit and was not used for either interplanetary mission. This pairing of vehicle with mission is the single most asked point in the chapter.