ISRO's SpaDeX opens new frontiers for Indian Defence
Indian Space Research Organisation’s (ISRO) success in docking two orbiting satellites in space, besides being a huge milestone in the country’s space exploration endeavours, will also give a fillip to the Indian military’s own fledgling space-based programmes.
Even before IRSO’s maiden Space Docking Experiment (SpaDeX) took off, the Indian Air Force had projected a requirement for “Autonomous Docking Operations for On-Orbit Maintenance and Refuelling (OOMR),” required for refuelling, maintaining and upgrading assets already in space.
The Indian Armed Forces primarily rely on satellites for strategic reconnaissance and, besides several existing satellites, had long-term plans for putting into orbit a vast constellation of satellites for surveillance and communications.
Use of satellites received an impetus after the 1999 Kargil conflict when the lack of indigenous capability was severely felt and India was saddled with outdated imagery of the war zone provided by certain foreign countries.
Terming it to be a historic moment, ISRO announced on January 16 that its Space Docking Experiment (SpaDeX) has been successfully completed, making India the fourth country after Russia, United States and China to develop this capability.
“Manoeuvre from 15-metre to 3-meter hold point completed. Docking initiated with precision, leading to successful spacecraft capture. Retraction completed smoothly, followed by rigidisation for stability,” ISRO said on its official X handle.
“Post docking, control of two satellites as a single object is successful. Undocking and power transfer checks to follow in coming days,” the post added.
SpaDeX was launched onboard the Polar Satellite Launch Vehicle (PSLV) from Sriharikota, off the coast of Odisha, in the evening of December 30, 2024 and the original schedule was to mate the two satellites, ‘SDX01 Chaser’ and ‘SDX02 Target’ on January 7.
The docking was postponed several times over technical issues such as requirement for additional simulations and greater drift of the satellites than expected during orbital manoeuvrers, prompting ISRO to proceed cautiously. On January 12, after reducing the inter-satellite distance in phases, the spacecrafts were brought as close as 3-meters apart and scientists studied the data generated for taking the last step.
A top ISRO scientist had earlier told The Tribune that a key spin off of the space docking technology would be extending the operational life of existing satellites. Space assets like geo-stationary satellites are very expensive but have a life of 8 - 10 years when propulsion units run out of fuel even though other onboard systems and sensors are fully functional. Space docking technology would enable replacing propulsion units repeatedly, allowing satellites to remain effective for many more years.
In November 2024, the IAF had projected a requirement through the Ministry of Defence’s Innovations for Defence Excellence (iDEX) scheme that ropes in the industry for meeting the Armed Forces’ requirements, for space docking technology.
“This project is about refuelling, maintenance and upgrading operations of a spacecraft, while in orbit, which entails the development of technologies for precise rendezvous, proximity and docking with the spacecraft and subsequent refuelling, maintenance and upgrading spacecraft operations,” the iDEX document stated.
“The expectation from the challenge is to design and develop technologies for docking operations with friendly/ cooperative spacecraft that need to be serviced, refuelled, or maintained. The technologies for precise guidance during all phases of operation – proximity, terminal guidance and docking and subsequent docking methodologies are envisioned to be designed and developed in this challenge,” the document added.
As of 2024, India operates nine satellites for defence purposes. Among them, two GSAT-7 and GSAT-7A are dedicated military satellites, while the rest like HySIS, CartoSat, EMISAT, RISAT and EOS, are dual purpose satellites. Six more satellites that will have military applications planned for launch soon.
After the retirement of the Soviet-era MiG-25R tri-sonic high-altitude reconnaissance aircraft that the IAF operated from 1981 to 2006, India depends upon satellites for strategic reconnaissance and imagery. The satellites are supplemented at the tactical level by unmanned aerial vehicles and fighter aircraft equipped with externally mounted camera pods.
In India, the Defence Space Agency (DSA), a tri-services agency under the Integrated Defence Staff headquartered at Bengaluru, is responsible for operating satellites and conducting space-warfare, including research, threat assessment, anti-satellite programmes and doctrinal aspects.
India’s foray into using outer space for military purposes bagan with the ‘Space Based Surveillance Phase – I’ project, which was approved by the Vajpeyee government in 2001. As a part of this, four satellites — Cartosat-2A, Cartosat-2B, EROS-B and RISAT-2 — were launched. Space Based Surveillance Phase – II was approved in 2013, which saw six satellites — Cartosat-2C, Cartosat-2D, Cartosat-3A, Cartosat-3B, Microsat-TD, RISAT-2A — being put in space, according to reports.
In October 2024, the Cabinet Committee on Security approved a proposal for the development, construction and launch of at least 52 satellites as a part of Space Based Surveillance Phase – III for round the clock, all weather reconnaissance and surveillance from space across land and sea domains, as well as enhance secure communications capability.
The project estimated to be worth Rs 26,968 crore will be supervised by the National Security Council Secretariat along with the DSA. ISRO will construct 21 satellites while the remaining 31 will be built by the private sector.
