The day after Independence Day, India launched the country's new Earth Observation Satellite, EOS-8, using the SSLV-D3 rocket at 9:17 AM from Satish Dhawan Space Center in Sriharikota. Along with EOS-8, a small satellite, SR-0 DEMOSAT, was also released as a passenger satellite. Both satellites will orbit at an altitude of 475 kilometers above the Earth. The satellites have successfully entered their designated orbits.
In its message on x, ISRO said, "The third developmental flight of SSLV was 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." As per ISRO, the six-and-a-half-hour countdown leading to the launch commenced at 2.47 am. This is the third and final developmental flight of the SSLV-D3/EOS-08 mission. The spacecraft is designed for a mission duration of one year.
ISRO chief S Somanath says, "...It was a very successful mission...As on today, with the data available, the mission is almost a 100% success with the satellite being placed in the correct orbit and all separation process happening nominally. We are very happy about completion of the development programme of SSLV with this third development flight...Now, beyond this, the program is to manufacture and launch this rocket for commercial purpose..."
The primary objectives of the EOS-08 mission include designing and developing a microsatellite, creating payload instruments compatible with the microsatellite bus, and incorporating new technologies required for future operational satellites, an ISRO release said earlier. Built on the Microsat/IMS-1 bus, the EOS-08 carries three payloads: the Electro-Optical Infrared Payload (EOIR), the Global Navigation Satellite System-Reflectometry Payload (GNSS-R), and the SiC UV Dosimeter.
The EOIR payload is designed to capture images in the Mid-Wave IR (MIR) and Long-Wave IR (LWIR) bands, both during the day and night, for applications such as satellite-based surveillance, disaster monitoring, environmental monitoring, fire detection, volcanic activity observation, and industrial and power plant disaster monitoring. The GNSS-R payload demonstrates the capability of using GNSS-R-based remote sensing for applications such as ocean surface wind analysis, soil moisture assessment, cryosphere studies over the Himalayan region, flood detection, and inland waterbody detection.
The spacecraft mission configuration is set to operate in a Circular Low Earth Orbit (LEO) at an altitude of 475 km with an inclination of 37.4°, and has a mission life of 1 year. The satellite has a mass of approximately 175.5 kg and generates power of around 420 W. It interfaces with the SSLV-D3/IBL-358 launch vehicle. EOS-08 marks a significant advancement in satellite mainframe systems such as an Integrated Avionics system, known as the Communication, Baseband, Storage, and Positioning (CBSP) Package, which combines multiple functions into a single, efficient unit. This system is designed with cold redundant systems using commercial off-the-shelf (COTS) components and evaluation boards, supporting up to 400 GB of data storage. Additionally, the satellite includes a structural panel embedded with PCB, an embedded battery, a Micro-DGA (Dual Gimbal Antenna), an M-PAA (Phased Array Antenna), and a flexible solar panel, each serving as key components for onboard technology demonstration.
Why This is Significant
SSLV stands for Small Satellite Launch Vehicle, and "D3" indicates that this is the third demonstration flight of the rocket. The SSLV is designed to launch mini, micro, and nano satellites. If this launch is successful, ISRO will deem the SSLV the third best rocket in the country. This rocket can send payloads up to 500 kg into low Earth orbit below 500 km, or 300 kg into Sun-Synchronous orbits, which are higher than 500 km. In this mission, it will reach an altitude of 475 km to deploy the satellite.
The SSLV rocket is 34 meters long, with a diameter of 2 meters, and weighs 120 tonnes. It can carry payloads of 10 to 500 kg to an altitude of 500 km and is ready for launch in just 72 hours. The SSLV is launched from launch pad one at the Satish Dhawan Space Center.
EOS-8: A Satellite for Disaster Management
The Earth Observation Satellite, EOS-8, is focused on environmental monitoring, disaster management, and technical demonstrations. Weighing 175.5 kg, it is equipped with three state-of-the-art payloads: the Electro-Optical Infrared Payload (EOIR), the Global Navigation Satellite System Reflectometry Payload (GNSS-R), and a Silicon Carbide (SiC) UV Dosimeter. The EOIR will capture mid and long-wave infrared images both day and night, providing vital data on natural disasters such as forest fires and volcanic activity.
The GNSS-R will analyze air over the sea surface, helping to detect soil moisture and flooding. Meanwhile, the SiC UV Dosimeter will measure ultraviolet radiation, contributing important data for the Gaganyaan mission.
Multifunctionality and Data Storage
The EOS-8 satellite will operate in a lower Earth orbit, at 475 kilometers. In addition to its environmental monitoring capabilities, it will provide technical assistance through its Integrated Avionics System, which includes a communication, baseband, storage, and positioning (CBSP) package. This integrated system allows for multiple functionalities within a single unit, boasting a data storage capacity of 400 GB.
Benefits of the Mission
The operational life of the EOS-8 mission is expected to be one year. Following the successful launch of SSLV-D3, the SSLV will achieve the status of a fully operational rocket. The SSLV has completed two previous flights: SSLV-D1 on August 7, 2022, and SSLV-D2 on February 10, 2023, which successfully delivered three satellites: EOS-07, Janus-1, and AzaadiSAT-2.
The SSLV offers a cost-effective alternative, being five to six times cheaper than the PSLV. As demand for small satellite launches continues to grow globally, ISRO developed this rocket to meet market needs. The cost of launching an SSLV is approximately Rs 30 crore, compared to the PSLV's cost of Rs 130 to 200 crore.