Introduction

• Since its founding, the Indian Space Research Organisation (ISRO) has been at the forefront of space technology and exploration.
• Over the years, the organisation has achieved several breakthroughs in space technologies by harnessing its critical resources, establishing India as a major player in the global space arena.
• ISRO has seen the progress of space technology and innovation in a variety of technological areas.
• Space technology has been one of the defining factors of the twentieth and twenty-first centuries. The launch of Sputnik by the Soviet Union in October 1957, and the subsequent space race to the moon, came to symbolise countries demonstrating their power and worldwide impact. These shining moments, such as the Apollo moon landing, were evidence of space technologies illuminating a clear route to the future, and it is now on the verge of a huge technological revolution.

Space Transportation System:

• The development of solid-propulsion-based Sounding Rockets capable of putting 30 kg of cargo at 120 km of altitude in the 1970s signalled the beginning of the space transportation system.
• The integration of solid and liquid propulsion, as well as the development of various key technologies, resulted in the development of the Polar Satellite Launch Vehicle (PSLV), which is capable of placing a 1700 kg payload into polar orbit.
• The domestic creation of a cryogenic propellant engine was a key technological leap in the construction of third-generation rockets, i.e., GSLV launch vehicles capable of placing a 2000 kg payload in Geo-Synchronous Transfer Orbit (GTO).
• Then, in order to launch high-throughput communication satellites, a more advanced launch vehicle, known as Launch Vehicle MK3 (LVM3), was developed.
•  ISRO has introduced the Small Satellite Launch Vehicle (SSLV), which is powered by the world's third largest solid boosters, as well as high-capacity liquid and cryogenic engines.

Infrastructure in Space

• The early 1970s saw the birth of ISRO's Space Infrastructure, which laid the groundwork for the design, construction, and operation of spacecraft. On April 19, 1975, the country's first satellite, 'Aryabhata,' was realised and launched.
• The indigenous development of key technologies for spacecrafts such as Advanced Propulsion, Power Systems, Thermal Systems, Deployable Structures, Space Bus Systems, Communication Systems, Ground Infrastructure, Optical, Microwave, Scientific & Communication Payloads, and so on has added to the country's self-reliance in spacecraft technology.
• Remote sensing capabilities has grown from a coarse resolution of 1 km to a fine resolution of 28 cm with day/night and all-weather capability.
• The number of communication transponders has likewise increased proportionally, from a single unit to 317.
• ISRO has mastered the capability of producing satellites ranging in weight from 2000 kg with 1 kW of power to 6000 kg with 14 kW of power, operating in various frequency bands and with wide, shaped, and highly focused spot capability for communications, sub-metre resolution, optical, multi-spectral, and microwave imaging for earth observations, and progressing from payload-based navigation solutions to a satellite constellation - NavIC (Navigation with Indian Constellation).

Interplanetary Missions and Space Science

• ISRO has successfully sailed to the Moon and Mars. The first lunar orbiter mission, Chandrayaan-1, introduced new experiences in hosting international payloads, calibration, data interpretation, and adopting global standards in science data formats, among other things. Chandrayaan-1's scientific triumph was the successful discovery of water on the Moon.
• In comparison to its predecessor, the Chandrayaan-2 mission was far more complicated, consisting of an Orbiter, Lunar Rover, and Lunar Lander ship.
• The Indian Space Research Organisation (ISRO) continues to investigate Mars with the first interplanetary mission to the red planet, the Mars Orbiter Mission (MOM), also known as Mangalyaan.

Space Applications

• The establishment of multi-object tracking radar, an integrated multimission ground segment for earth observation satellites, Polarimeteric Doppler Weather Radar, and a state-of-the-art advanced ground station for Earth Observation satellites at Bharti station have facilitated the uninterrupted use of satellite services.
• The revolution in imaging technologies such as Pushbroom, 3-Tier Imaging, Step-Stare, Stereo Imaging, Scatterometer, Synthetic Aperture Radar (SAR), Ground Penetrating Radar (GPR) Altimeter, TDI imaging, VHR imaging, etc., in the domain of Earth Observation served to accomplish 47 missions with capabilities of spatial resolution from 1 km to 28 cm, temporal resolution of 24 days to 2.5 days, and spectral resolution of 7 bits to 14 bits.

Human Space Exploration

• At the moment, ISRO is actively pursuing the first human spaceflight mission Gaganyan, which will send astronauts into space and return them safely.
• A new vehicle, known as a Test Vehicle (TV), has been created to test crucial crew-related systems. ISRO executed a significant development test.
• Integrated Main Parachute Airdrop Test (IMAT)' to mimic various failure conditions of the parachute system before it is certified for use in the first human spaceflight mission. Gaganyaan is well on its way to completing its objective.

Technology Advancement Continues

• ISRO created the Reusable Launch Vehicle (RLV) programme to create space aircraft and shuttles that can ascend to orbit, stay there, re-enter, and land on a runway like an aeroplane.
• Under the Air Breathing Propulsion Project (ABPP), ISRO is actively developing technology for an Air Breathing Two Stage to Orbit (AB TSTO) vehicle.
• ISRO has been actively pursuing several R&D programmes in Space Robotics, including Vyommitra (Humanoid robot), Lander and Rover for the Chandrayaan-3 mission, On-orbit Satellite Refuelling, Planetary Rock Sampler, Space-based robotic manipulator, Robotic arm-based umbilical systems, and 3D printing in Space.