With reference to Indian satellites and their launchers, consider the following statements: 1. All the INSAT-series of satellites were launched abroad 2. PSLVs were used to launch IRS-series of satellites 3. India used the indigenously built cryogenic engines for the first time for powering the third stage of GSLV 4. GSAT, launched in the year 2001, has payloads to demonstrate digital broadcasts and internet services Which of these statements are correct?

The correct answer is Option 3 (1, 2 and 4). Below is the comprehensive explanation:

• Statement 1 is correct: Historically, all satellites in the INSAT (Indian National Satellite System) series were launched using foreign rockets, primarily the European Ariane launchers, due to their heavy mass exceeding the capacity of Indian launch vehicles at that time.
• Statement 2 is correct: The Polar Satellite Launch Vehicle (PSLV) was specifically designed to place IRS (Indian Remote Sensing) satellites into Sun-Synchronous Polar Orbits, establishing India's self-reliance in earth observation.
• Statement 3 is incorrect: While the GSLV uses a cryogenic third stage, India did not use an indigenously built engine for the first time in its initial GSLV flights. Early GSLV missions (including GSLV-D1 in 2001) used Russian-supplied cryogenic engines. The first successful flight with an indigenous cryogenic engine (CE-7.5) occurred much later in 2014 (GSLV-D5).
• Statement 4 is correct: GSAT-1, launched in 2001, was an experimental communication satellite designed to test technologies like digital audio/video broadcasting and internet services.

Since statements 1, 2, and 4 are accurate, Option 3 is the right choice.