The Indian Space Research Organisation (ISRO) has consistently pushed the boundaries of space exploration and technology, establishing India as a prominent player in the global space arena. The 2023-2024 annual report provides a comprehensive overview of ISRO’s major activities, achievements, and future plans, highlighting its commitment to advancing space science and technology for the benefit of society.
Organizational Structure and Key Centers
ISRO operates under the Department of Space (DOS), which formulates policies and oversees the implementation of India’s space program. The Space Commission plays a crucial role in promoting the development and application of space science and technology for the country’s socio-economic growth. The DOS executes these programs primarily through ISRO and other institutions like the Physical Research Laboratory (PRL), National Atmospheric Research Laboratory (NARL), and North Eastern-Space Applications Centre (NE-SAC).
ISRO’s vast network of centers across India specializes in various aspects of space research and development. The Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram leads the design and development of launch vehicles, including the Polar Satellite Launch Vehicle (PSLV), Geosynchronous Satellite Launch Vehicle (GSLV), and Small Satellite Launch Vehicle (SSLV). The U R Rao Satellite Centre (URSC) in Bengaluru focuses on building satellites for communication,navigation, remote sensing, and scientific missions. The Satish Dhawan Space Centre (SDSC) in Sriharikota serves as India’s spaceport, providing launch base infrastructure. The Liquid Propulsion Systems Centre (LPSC) in Thiruvananthapuram and Bengaluru develops advanced propulsion systems for launch vehicles and spacecraft.
Other vital centers include the Space Applications Centre (SAC) in Ahmedabad, responsible for developing space-borne and air-borne instruments and their applications; the Human Space Flight Centre (HSFC) in Bengaluru, dedicated to India’s human spaceflight program, Gaganyaan; the National Remote Sensing Centre (NRSC) in Hyderabad, managing ground stations for receiving and processing satellite data; and the ISRO Propulsion Complex (IPRC) in Mahendragiri,handling the assembly, integration, and testing of liquid propulsion systems.
Major Activities and Achievements
Earth Observation, Data Processing, and Applications
ISRO’s Earth Observation program plays a crucial role in providing valuable data for various applications, including weather forecasting, disaster management, natural resource management, and environmental monitoring. The Integrated Multi-Mission Ground Segment for Earth Observation Satellites (IMGEOS) at Shadnagar and the Antarctica Ground Station for Earth Observation Satellites (AGEOS) at Bharati Station ensure efficient data reception and processing.
ISRO has made significant strides in satellite data processing and dissemination, generating and providing data products to users through the Bhuvan geoportal. The opening of IRS (Indian Remote Sensing) data on a free basis under the Space Policy 2023 has further enhanced data accessibility and utilization.
Remote sensing applications have been instrumental in diverse fields. In agriculture, ISRO’s efforts have led to improved crop yield estimation, crop mapping, and drought impact assessment. Water resource management has benefited from the development of a national modeling framework and the generation of various products like evapotranspiration maps and flood early warning systems. Forestry and ecology applications have focused on forest biomass estimation and the identification of long-duration fire events. Land resource applications include the generation of Land Use/Land Cover maps and wetland inventories.
Space Applications
Satellite communication remains a cornerstone of ISRO’s activities, with a fleet of 18 communication satellites supporting various services like television broadcasting, DTH television, telecommunication, VSATs, and strategic communication.High Throughput Satellites (HTS) like GSAT-19, GSAT-11, and GSAT-29 have significantly enhanced bandwidth and connectivity across the country.
ISRO’s telemedicine program has been a boon for healthcare in remote and rural areas, connecting medical colleges and hospitals to major specialty hospitals through satellite communication. The program has expanded to include nodes for defense and paramilitary forces in challenging terrains.
Tele-education initiatives have leveraged satellite communication to deliver educational programs to students in remote regions, supplementing curriculum-based education and providing teacher training.
Satellite meteorology has witnessed advancements with INSAT-3D and INSAT-3DR satellites providing crucial inputs for weather forecasting. The INSAT Meteorological Data Processing System (IMDPS) at the India Meteorological Department (IMD) processes and disseminates satellite data, contributing to improved weather predictions and disaster warnings.
The Satellite Aided Search and Rescue (SAS&R) program, in collaboration with the international COSPAS-SARSATprogram, has been instrumental in providing distress alert and position location services. India has established Local User Terminals (LUTs) and the Indian Mission Control Centre (INMCC) to support search and rescue operations, saving numerous lives.
Navigation Systems
India’s independent regional navigation satellite system, Navigation with Indian Constellation (NavIC), provides accurate positioning and timing services over India and its surrounding region. NavIC is being integrated into various civilian sectors like transportation, aviation, maritime, and timing applications. The GPS Aided Geo Augmented Navigation (GAGAN) system, jointly developed by ISRO and the Airports Authority of India (AAI), enhances the accuracy and integrity of GPS signals for civil aviation.
Space Science Exploration and Research
ISRO’s space science program has made remarkable progress in exploring the mysteries of the universe. The Chandrayaan-3 mission achieved a historic soft landing on the Moon’s south pole, enabling the deployment and operation of scientific payloads for in-situ lunar exploration. Preliminary results from Chandrayaan-3 have provided valuable insights into the lunar surface, plasma environment, and regolith properties.
The Aditya-L1 mission, India’s first solar mission, was successfully launched and is currently en route to its designated halo orbit around the Sun-Earth L1 point. The mission aims to study various aspects of the Sun, including its corona, solar wind, and energetic particles.
Other ongoing space science missions, such as Chandrayaan-2 and AstroSat, continue to provide valuable data and contribute to scientific discoveries.
The Launch Vehicles: The Backbone of India’s Space Program
The success of any space program hinges on its ability to reliably and efficiently launch payloads into orbit. ISRO has developed a diverse fleet of launch vehicles, each with unique capabilities, to cater to the varying needs of its missions.These launch vehicles have been instrumental in placing satellites into orbit for communication, navigation, earth observation, and scientific research, as well as carrying out interplanetary missions. The 2023-2024 annual report highlights the significant achievements and ongoing developments in ISRO’s launch vehicle program.
Polar Satellite Launch Vehicle (PSLV)
The PSLV is ISRO’s workhorse launch vehicle, known for its reliability and versatility. It is a four-stage rocket capable of launching satellites into various orbits, including polar and sun-synchronous orbits. The PSLV has been used for a wide range of missions, from launching India’s first lunar probe, Chandrayaan-1, to deploying large constellations of small satellites.
- Specifications:
- Height: 44.4 meters
- Mass: 320 tons
- Payload capacity to Low Earth Orbit (LEO): 1,750 kg
- Payload capacity to Sun-Synchronous Orbit (SSO): 1,425 kg
- Stages:
- First stage: Solid propellant
- Second stage: Liquid propellant
- Third stage: Solid propellant
- Fourth stage: Liquid propellant
- Launch History: The PSLV has an impressive track record, with over 50 successful launches since its first flight in 1993. In 2023-2024, the PSLV continued its success with missions like PSLV-C55/TeLEOS-2, PSLV-C56/DS-SAR,PSLV-C57/ADITYA-L1, and PSLV-C58/XPoSat. These missions demonstrated the PSLV’s capability to launch multiple satellites into different orbits and carry out scientific experiments using the spent fourth stage as an orbital platform.
Geosynchronous Satellite Launch Vehicle (GSLV)
The GSLV is a three-stage launch vehicle designed to place communication satellites into geostationary transfer orbits. It features a solid first stage, a liquid second stage, and a cryogenic upper stage. The GSLV has played a crucial role in expanding India’s communication satellite capabilities.
- Specifications:
- Height: 49.13 meters
- Mass: 414.75 tons
- Payload capacity to Geosynchronous Transfer Orbit (GTO): 2,500 kg
- Stages:
- First stage: Solid propellant
- Second stage: Liquid propellant
- Upper stage: Cryogenic propellant
- Launch History: The GSLV has had a successful launch history, with notable missions like GSLV-F12/NVS-01 and GSLV-F14/INSAT-3DS in 2023-2024. These missions demonstrated the GSLV’s capability to launch navigation and meteorological satellites into geostationary orbits.
Geosynchronous Satellite Launch Vehicle Mark III (LVM3)
The LVM3, formerly known as GSLV Mk-III, is India’s heaviest and most powerful launch vehicle. It is a three-stage rocket with two S200 solid strap-on motors, a liquid core stage (L110), and a cryogenic upper stage (C25). The LVM3 is capable of launching heavy payloads, including large communication satellites and interplanetary missions, into orbit.
- Specifications:
- Height: 43.5 meters
- Mass: 640 tons
- Payload capacity to GTO: 4,000 kg
- Payload capacity to LEO: 8,000 kg
- Stages:
- Two S200 solid strap-on motors
- L110 liquid core stage
- C25 cryogenic upper stage
- Launch History: The LVM3 has had several successful launches, including the LVM3-M3/OneWeb India-2 mission and the LVM3-M4/Chandrayaan-3 mission in 2023-2024. These missions showcased the LVM3’s capability to launch large constellations of satellites and carry out complex lunar missions.
Small Satellite Launch Vehicle (SSLV)
The SSLV is a small-lift launch vehicle designed for launching small satellites into Low Earth Orbit (LEO). It is an all-solid three-stage rocket with a quick turnaround time and launch-on-demand capability. The SSLV is expected to play a crucial role in meeting the growing demand for small satellite launches, both for national and commercial purposes.
- Specifications:
- Height: 34 meters
- Mass: 120 tons
- Payload capacity to LEO (500 km): 500 kg
- Stages:
- All three stages are solid propellant
- Launch History: The SSLV had its second developmental flight, SSLV-D2/EOS-07, in 2023. This mission successfully placed the EOS-07 earth observation satellite and two co-passenger satellites into orbit, validating the SSLV’s launch vehicle systems and demonstrating its launch-on-demand capability.
Reusable Launch Vehicle (RLV)
The development of a Reusable Launch Vehicle (RLV) is a testament to ISRO’s commitment to innovation and cost-effectiveness in space transportation. The RLV program aims to create a launch vehicle that can be recovered and reused after each mission, significantly reducing the cost of access to space. The current focus of the RLV program is on demonstrating critical technologies required for developing a winged body reentry vehicle, similar to an aircraft.
RLV-LEX Missions
- RLV LEX Mission: In April 2023, ISRO successfully conducted the Autonomous Landing Experiment (LEX) of the RLV at the Aeronautical Test Range (ATR) of DRDO. The RLV was carried to an altitude of 4.5 km by an Indian Air Force helicopter and then released to perform a controlled, autonomous descent and landing on the runway within 60 seconds. This experiment successfully demonstrated critical technologies like autonomous navigation, guidance & control systems, and landing gears.
- RLV LEX-02 Mission: In March 2024, ISRO conducted the second autonomous runway landing experiment (LEX-02) of the RLV. The RLV was released from a Chinook helicopter at an altitude of 4.5 km and successfully landed on the runway within 60 seconds, even with an intentional lateral shift before release. This further validated the robustness of the onboard autonomous systems and the performance of the landing gears.
The Path Ahead
The data and experience gained from these RLV-LEX missions will be crucial in paving the way for future orbital flight and autonomous re-entry missions of a winged RLV. The development of reusable launch vehicles is a complex and challenging endeavor, but the potential benefits in terms of cost reduction and increased access to space make it a worthwhile pursuit. ISRO’s progress in the RLV program demonstrates its dedication to pushing the boundaries of space technology and making space exploration more accessible and sustainable.
Gaganyaan – India’s Human Spaceflight Program
Gaganyaan, India’s ambitious human spaceflight program, is making steady progress towards its goal of sending Indian astronauts to space. The successful Test Vehicle Abort Mission-01 (TV-D1) demonstrated the safe escape and recovery of the Crew Module in case of an emergency during launch.
Various critical systems and technologies for Gaganyaan are under development, including the Crew Module, Service Module, Crew Escape System, and Environmental Control and Life Support System (ECLSS). Extensive testing and qualification programs are being conducted to ensure the safety and reliability of these systems.
Crew training simulators are also being developed to prepare astronauts for the physiological and psychological challenges of spaceflight. The program also focuses on developing critical technologies like the Orbital Module, life support systems, and human-centric technologies.
The successful testing of the Crew Escape System and the recovery of the Crew Module on board the Test Vehicle (TV-D1) marked a significant milestone in the Gaganyaan program. The development of various other critical systems,including the Service Module and the Environmental Control and Life Support System (ECLSS), is progressing steadily.
The Future of Indian Space Exploration
The 2023-2024 annual report provides a glimpse into ISRO’s ambitious plans for the future. The organization is actively working on several projects that will further enhance India’s capabilities in space exploration and technology.
The development of a semi-cryogenic propulsion system and an uprated cryogenic stage for the LVM3 launch vehicle will significantly increase its payload capacity, enabling the launch of heavier satellites and interplanetary missions. Research and development efforts are also underway to develop key technologies for hypersonic air-breathing vehicles, which could advance space transportation by enabling more efficient and cost-effective access to space.
ISRO’s commitment to international collaboration is evident in its partnerships with various space agencies and organizations worldwide. These collaborations facilitate knowledge sharing, joint missions, and capacity building in the space sector.
Summary
The 2023-2024 annual report showcases ISRO’s remarkable achievements and ambitious plans for the future. From successful lunar landings and solar missions to advancements in launch vehicle technology and human spaceflight, ISRO continues to inspire and push the boundaries of space exploration. The organization’s focus on self-reliance, innovation,and collaboration positions India as a leading force in the global space community. With its unwavering commitment to space science and technology, ISRO is poised to make even greater strides in the years to come, contributing to India’s growth and development while unraveling the mysteries of the cosmos.
