UPSC 2018: 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?

PSLV is a four-stage launcher optimized for placing Earth-observation/remote-sensing satellites in sun-synchronous polar orbits useful for resource-mapping, whereas GSLV is designed to lift heavier communication satellites to geostationary transfer orbit, so Statement 1 is correct. Satellites put in polar orbits by PSLV do NOT appear stationary in the sky (only geostationary‐orbit satellites do), so Statement 2 is wrong. GSLV Mk III (LVM3) is a three-stage vehicle with two solid S200 strap-ons, one liquid L110 core and one cryogenic C25 upper stage—not a four-stage solid-liquid alternation—so Statement 3 is wrong ([isro.gov.in](https://www.isro.gov.in/ISRO_EN/PSLV_CON.html?utm_source=openai))