Which one of the following PSLVs, launched by ISRO, is not correctly matched with their Missions? PSLV — Mission
- (a)PSLV C60 — SPADEX
- (b)PSLV C59 — Proba-3
- (c)PSLV C58 — XPoSat
- (d)PSLV C57 — DS-SAR
Correct — D, PSLV C57 — DS-SAR. PSLV-C57 carried Aditya-L1, India's first solar observatory, on 2 September 2023; the spacecraft reached its halo orbit about the Sun-Earth L1 point on 6 January 2024. DS-SAR did fly on a PSLV, but on C56, a dedicated commercial mission through NSIL launched on 30 July 2023 with a Singaporean radar-imaging satellite as the primary payload and six co-passengers, all of them Singaporean. So the two are one flight apart, which is why the pairing looks right at speed. The other three are correct as printed. PSLV-C60 launched SpaDeX on 30 December 2024, the twin 220-kilogram satellites that performed India's first autonomous in-space docking on 16 January 2025, along with the POEM-4 platform carrying 24 experiments. PSLV-C59 launched the European Space Agency's Proba-3 on 5 December 2024, a pair of spacecraft that fly about 150 metres apart so that one casts its shadow on the other's coronagraph, making an artificial solar eclipse. PSLV-C58 launched XPoSat on 1 January 2024 to study the polarisation of cosmic X-rays in the 2 to 30 keV band.
- (a)PSLV C60 — SPADEX — Correctly matched, so it cannot be the answer to a 'not correctly matched' stem. C60 flew the twin SpaDeX satellites on 30 December 2024; they docked on 16 January 2025.
- (b)PSLV C59 — Proba-3 — Correctly matched. C59 launched the European Space Agency's Proba-3 formation-flying pair on 5 December 2024, a commercial launch for ESA.
- (c)PSLV C58 — XPoSat — Correctly matched. C58 launched XPoSat, India's X-ray polarimeter satellite, on 1 January 2024.
The PSLV is ISRO's four-stage workhorse, alternating solid and liquid stages, built for sun-synchronous polar orbits and used for Earth observation, small scientific payloads and commercial rideshares. Flight numbers run in sequence — C56, C57, C58 and so on — so the numbering is itself a chronology, and a mismatch question of this kind is usually built by shifting one payload by a single flight. The five relevant flights here span July 2023 to December 2024.
Do not try to recall four pairs independently. Put them on a timeline and the odd one falls out. C56 in July 2023 was the Singapore commercial mission with DS-SAR; C57 in September 2023 was Aditya-L1, which is far too prominent an Indian mission to have been anything else; C58 opened 2024 on 1 January with XPoSat; C59 in December 2024 was ESA's Proba-3; C60 closed the year on 30 December with SpaDeX. Aditya-L1 is the anchor — once you place it on C57, option (d) is dead. It is worth noticing what the sequence says about ISRO's business as well: of these five flights, two carried Indian science missions, one a technology demonstration and two were flown for foreign customers.
- PSLV-C56 launched DS-SAR for Singapore on 30 July 2023, a dedicated commercial mission through NSIL with six co-passenger satellites.
- PSLV-C57 launched Aditya-L1 on 2 September 2023; it entered a halo orbit around the Sun-Earth L1 point on 6 January 2024.
- PSLV-C58 launched XPoSat on 1 January 2024 to study the polarisation of cosmic X-rays in the 2-30 keV band.
- PSLV-C59 launched the European Space Agency's Proba-3 on 5 December 2024, a formation-flying pair that creates an artificial solar eclipse.
- PSLV-C60 launched SpaDeX on 30 December 2024; the twin satellites docked autonomously on 16 January 2025, with the POEM-4 platform carrying 24 experiments.
- Shifting a payload by one flight number; DS-SAR is C56, not C57, which is the whole item.
- Assuming any solar mission belongs to the flight that carried Proba-3; Aditya-L1 is India's, Proba-3 is ESA's, and they flew fifteen months apart.
- Forgetting that the POEM platform on many PSLV flights carries experiments of its own after the main separation.
As a mismatched-pair item like this one, or as a chronological ordering of recent ISRO missions.
With reference to India's satellite launch vehicles, consider the following statements: 1. PSLVs launch the satellites useful for Earth resources monitoring whereas GSLVs are designed mainly to launch communication satellites. 2. Satellites launched by PSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth. 3. GSLV Mk III is a four-stage launch vehicle with the first and third stages using solid rocket motors; and the second and fourth stages using liquid rocket engines. Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 and 3
- (c) 1 and 2
- (d) 3 only
Answer(a) 1 only
The vehicle behind every pair in this question. Knowing that the PSLV is built for polar, sun-synchronous orbits rather than geostationary ones explains why its manifest is full of Earth-observation, scientific and commercial rideshare payloads.
- practice — not a real PYQ
Aditya-L1, India's first solar observatory, was launched by which PSLV flight?
- (a)PSLV-C55
- (b)PSLV-C56
- (c)PSLV-C57
- (d)PSLV-C58
Answer(c) PSLV-C57 — launched on 2 September 2023; the spacecraft entered its halo orbit around the Sun-Earth L1 point on 6 January 2024.
- practice — not a real PYQ
The SpaDeX mission launched by ISRO in December 2024 was intended to demonstrate which capability?
- (a)Soft landing on the Moon
- (b)Autonomous rendezvous and docking of two satellites in orbit
- (c)Reusable launch vehicle landing on a runway
- (d)Human-rated crew escape
Answer(b) Autonomous rendezvous and docking of two satellites in orbit — the twin satellites docked on 16 January 2025.