Which was the first satellite of India, launched in 1975 from the Soviet Union?

The correct answer is D, 1984. Wing Commander Rakesh Sharma flew in April 1984 aboard the Soviet spacecraft Soyuz T-11 as part of a joint programme between the Soviet Union and India, and spent about eight days aboard the Salyut 7 space station. He thus became the first Indian to travel into space. He is remembered for his reply when the Prime Minister asked how India looked from up there, and he was awarded the Ashoka Chakra.

Options A, B and C give 1981, 1982 and 1983, all near years placed there to see whether the date is firmly held. Fix the year by tying it to two other facts of the same decade: India launched its own satellite Aryabhata in 1975 and put Rohini in orbit with an Indian rocket in 1980, and Rakesh Sharma flew four years after that. The second Indian origin astronauts, Kalpana Chawla and Sunita Williams, flew with the American programme much later.

The correct answer is B, Gaganyaan. Gaganyaan is the programme under which the Indian Space Research Organisation is preparing to send Indian astronauts into a low orbit around the Earth in a crew module of its own and bring them back safely. The programme includes uncrewed test flights, a crew escape system and a human rated launch vehicle. Its first flight test of the crew escape system, called TV-D1, took place in October 2023.

Option A, Mangalyaan, is the Mars Orbiter Mission, an uncrewed spacecraft that reached Mars orbit in 2014. Option C, Chandrayaan-2, was an uncrewed Moon mission of 2019 with an orbiter, a lander and a rover. Option D, Aditya-L1, is the solar observatory launched in 2023 to a halo orbit around the Lagrange point L1. None of the three carries a crew, so only Gaganyaan can be the human spaceflight programme.

The correct answer is B, STUDSAT. STUDSAT, short for Student Satellite, was the first pico satellite built in India. A pico satellite is one that weighs under about one kilogram, and STUDSAT weighed less than that. It was built by students of engineering colleges in Bengaluru and Hyderabad and was launched in 2010 by a PSLV flight as an auxiliary payload, carrying a small camera for imaging the Earth.

Option A, INSAT, is not a single satellite but the Indian National Satellite System, a family of heavy communication satellites in geostationary orbit. Option C, GSAT-4, was an experimental communication satellite that was lost when its launch vehicle failed in 2010. Option D, ANUSAT, was built by Anna University and launched in 2009, but it was a micro satellite of about forty kilograms, not a pico satellite, which is exactly the distinction the question is testing.

The correct answer is B, to measure the vertical temperature profile of the lunar regolith. ChaSTE was carried on the Vikram lander of Chandrayaan-3. It has a probe fitted with a set of temperature sensors, which was pushed into the lunar soil to a depth of about ten centimetres near the south polar region. From its readings scientists can see how heat moves through the top layer of the Moon, which tells them about the thermal properties of the soil at a place never measured before.

Option A, the geological composition, was the task of the two instruments on the Pragyan rover, which used alpha particles and a laser to find the elements in the soil. Option C is wrong because the Moon has only an extremely thin envelope of gas rather than an atmosphere with measurable pressure of the usual kind. Option D, the magnetic field, was not the aim of ChaSTE; the lander instead carried instruments to record moonquakes and to study the plasma near the surface.

The correct answer is B, Sindhu Netra Satellite. Sindhu Netra was developed by the Defence Research and Development Organisation and was placed in orbit in February 2021 by the PSLV-C51 flight, the same flight whose main payload was the Amazonia-1 satellite of Brazil. The satellite is meant to watch shipping in the Indian Ocean Region and to help identify warships and merchant vessels moving through those waters, which supports maritime awareness for the armed forces.

Option A, the Satish Dhawan Satellite, was also aboard the same PSLV-C51 flight, but it was a small satellite built by a private Indian team and is not a surveillance satellite. Options C and D, Sindhu Durga and Sri Shakti, are invented names that sound plausible beside the correct one. Remember the pairing of PSLV-C51 with Amazonia-1 as its main payload and Sindhu Netra among the rideshare satellites.