Isro Missions and Milestones Timeline

The Indian Space Research Organisation (ISRO) has evolved from a modest sounding-rocket launch program into one of the premier space agencies in the world. Established in 1969 under the vision of Dr. Vikram Sarabhai, ISRO built indigenous capability across satellite manufacturing, launch vehicle development, deep space exploration, and human spaceflight technology.

Genesis and Foundational Years (1962–1979)

Key Early Institutional and Satellite Milestones

• INCOSPAR Formation (1962): The Department of Atomic Energy set up the Indian National Committee for Space Research (INCOSPAR) under Dr. Vikram Sarabhai to initiate space research.
• First Sounding Rocket (1963): On November 21, 1963, a Nike-Apache sounding rocket launched from Thumba Equatorial Rocket Launching Station (TERLS) near Thiruvananthapuram, marking the launch of India’s space program.
• Establishment of ISRO (1969): ISRO was formally established on August 15, 1969, superseding INCOSPAR. It was placed under the newly formed Department of Space in 1972.
• Aryabhata Satellite (1975): India’s first satellite, Aryabhata, was launched on April 19, 1975, using a Soviet C-1 Interkosmos launch vehicle from Kapustin Yar.
• SITE Program (1975–1976): The Satellite Instructional Television Experiment used the American ATS-6 satellite to broadcast educational programs directly to 2,400 rural Indian villages.
• Bhaskara-I (1979): Launched on June 7, 1979, Bhaskara-I was India’s first experimental remote sensing satellite equipped with TV cameras and microwave radiometers.

Evolution of Launch Vehicle Capabilities

Launch Vehicle Generations and Operational Transition

• SLV-3 (1980): Satellite Launch Vehicle-3 was a four-stage, solid-propellant launcher. On July 18, 1980, it placed the Rohini (RS-1) satellite into orbit, making India the sixth spacefaring nation with independent launch capability.
• ASLV (1987): The Augmented Satellite Launch Vehicle was a five-stage launcher developed to test vertical integration, strap-on booster technology, and closed-loop guidance systems.
• PSLV (1993/1994): The Polar Satellite Launch Vehicle completed its first successful operational flight in October 1994 (IRS-P2). It incorporates alternate solid and liquid stages and functions as ISRO’s principal operational launcher.
• GSLV Mk II (2001/2014): The Geosynchronous Satellite Launch Vehicle introduced a three-stage design featuring an indigenous Cryogenic Upper Stage (CUS), capable of placing 2-tonne class communication payloads into Geostationary Transfer Orbit (GTO).
• LVM3 / GSLV Mk III (2014/2017): Heavy-lift vehicle equipped with two S200 solid boosters, an L110 core liquid stage, and a C25 cryogenic upper stage. It carries up to 4 tonnes to GTO and 10 tonnes to Low Earth Orbit (LEO).
• SSLV (2022–2024): Small Satellite Launch Vehicle developed for low-cost, flexible, on-demand launching of small satellites weighing up to 500 kg into low Earth orbits.

Major Planetary, Space Science, and Deep Space Missions

Key Deep Space and Space Science Landmarks

Satellite Constellations and Application Programs

Communication, Navigation, and Earth Observation Systems

• INSAT and GSAT Systems: Major geostationary communication constellations handling telecommunications, direct-to-home broadcasting, VSAT networks, and meteorological monitoring.
• Earth Observation Network: Includes Cartosat (high-resolution imaging), Resourcesat (land monitoring), OceanSat (oceanography), and RISAT (radar imaging) series.
• NavIC (IRNSS): Navigation with Indian Constellation consists of seven operational satellites providing independent positioning services across India and extending 1,500 km beyond its borders.
• NISAR Mission: Joint Earth-observing satellite developed with NASA featuring dual-frequency Synthetic Aperture Radar (L-band and S-band) to track global land surface changes.

Technology Demonstrators and Future Horizons

Advanced Capability Demonstrations

• Space Capsule Recovery Experiment (SRE-1, 2007): Tested thermal protection systems, navigation guidance, and ocean splashdown recovery capabilities.
• CARE Mission (2014): Tested the atmospheric re-entry parameters of an uncrewed crew module during the inaugural flight of LVM3.
• RLV-LEX Missions (2023–2024): Autonomous landing flight experiments testing winged reusable launch vehicle configurations.
• Gaganyaan Program: India’s flagship human spaceflight initiative aimed at carrying a crew of three astronauts to a 400 km orbit. Tested via the TV-D1 flight in 2023.

Important Facts and Trivia

• Dr. Vikram Sarabhai is honored as the Father of the Indian Space Program.
• Following the success of the SpaDEx mission, India became the fourth nation to achieve autonomous satellite docking in space.
• On February 15, 2017, PSLV-C37 set a world record by placing 104 satellites into orbit during a single launch.
• August 23 is designated as National Space Day in India to commemorate the successful landing of Chandrayaan-3 on the Moon.
• Satish Dhawan Space Centre (SDSC) SHAR in Sriharikota, Andhra Pradesh, functions as India’s primary launch facility.
• Master Control Facility (MCF) locations at Hassan in Karnataka and Bhopal in Madhya Pradesh track and manage geostationary satellites.
• ISRO Telemetry, Tracking and Command Network (ISTRAC) operates its primary hub in Bengaluru, Karnataka.