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-staged 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 ✓ UPSC's answer
- (b) 2 and 3
- (c) 1 and 2
- (d) 3 only
Why the answer is (a)
• Statement 1 is correct: PSLV places Earth-observation and other satellites in polar/sun-synchronous orbits, while GSLV is built to put heavier communication satellites into geosynchronous transfer orbit.
• Statement 2 is wrong: PSLV satellites in low polar orbits move across the sky; only geostationary satellites (launched by GSLV) appear fixed.
• Statement 3 is wrong: GSLV Mk III (LVM3) is a three-stage vehicle — two solid strap-on boosters (S200), a liquid core (L110) and a cryogenic upper stage (C25) — not four stages.
• Hence 1 only, option (a).
Why the other options are wrong
- (b) 2 and 3
- Statements 2 and 3 are wrong: PSLV satellites are not geostationary and Mk III has three stages.
- (c) 1 and 2
- Statement 2 is wrong: PSLV satellites do not appear fixed.
- (d) 3 only
- Statement 3 is wrong: Mk III is three-staged.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2018, held on 3 June 2018. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.