SRIHARIKOTA: The Indian Space Research Organisation (ISRO) has successfully launched its third and final developmental flight of the Small Satellite Launch Vehicle (SSLV), marking a significant milestone in its space exploration efforts. The launch took place at 9:17 am IST from the first launch pad at the Satish Dhawan Space Centre, located about 135 km east of Chennai.
The SSLV-D3 rocket carried the primary Earth Observation Satellite, EOS-08, and successfully placed it into its intended orbit. The mission also included a SR-O DEMOSAT satellite developed by Space Kidz India, weighing 200 grams, which separated successfully within minutes of the main payload. The successful completion of this mission signifies the end of the SSLV developmental flights and sets the stage for commercial launches.
"The third developmental flight of SSLV is successful. The SSLV-D3 placed EOS-08 precisely into the orbit. This marks the successful completion of ISRO/DOS's SSLV Development Project. With technology transfer, the Indian industry and @NSIL_India will now produce SSLV for commercial missions," ISRO stated in a post on X.
The SSLV-D3 mission, initially scheduled for August 15, was rescheduled by 24 hours and launched within a 60-minute window. Despite the maiden mission of the SSLV in August 2022 falling short of its objectives, the subsequent flight, SSLV-D2-EOS-07 in February 2023, was a success.
The SSLV rocket, measuring 34 meters in height, is designed to place mini, micro, or nano satellites weighing up to 500 kg into Low Earth Orbit (LEO) at altitudes below 500 km. The rocket’s design features three solid propulsion stages and a liquid module as a terminal stage, offering low-cost access to space, minimal launch infrastructure, and flexible, on-demand launches.
A former ISRO scientist noted that the cost of an SSLV mission is approximately 20-30% less than that of a Polar Satellite Launch Vehicle (PSLV) mission, and that SSLVs can be launched within two days of planning. The SSLV can also be used for missions to place satellites into Sun-Synchronous Orbits (SSO), depending on customer requirements.
The primary objectives of the SSLV-D3 mission included designing and developing a micro-satellite, creating payload instruments compatible with the micro-satellite bus, and integrating new technologies for future operational satellites. The payloads on the mission included:
Electro-Optical Infrared Payload (EOIR): For satellite-based surveillance, disaster and environmental monitoring, fire detection, and volcanic activity.
Global Navigation Satellite System-Reflectometry (GNSS-R): For analyzing ocean surface winds, assessing soil moisture, studying the cryosphere over the Himalayan region, and detecting floods and inland waterbodies.
SiC UV Dosimeter: To monitor UV irradiance at the viewport of the Crew Module in the Gaganyaan Mission and to serve as a high-dose alarm sensor for gamma radiation.
The EOS-08 satellite is planned to be placed in a Circular Low Earth Orbit at an altitude of approximately 475 km with an inclination of 37.4 degrees. It has a mission life of one year and includes advanced satellite systems such as an Integrated Avionics System, a structural panel embedded with PCB, a Micro-Dual Gimbal Antenna (Micro-DGA), a Micro-Phased Array Antenna, and a flexible solar panel.
Looking ahead, NewSpace India Ltd (NSIL) is preparing for its first dedicated commercial SSLV launch, planned for 2026, which will deploy the Optimus satellite built by the Australia-based Space Machines Company.