ISRO to launch earth observation satellite on Friday

SRIHARIKOTA: ISRO is all set to launch an earth observation satellite EOS-08 onboard the third and final developmental flight of its Small Satellite Launch Vehicle on Friday morning.

The Satish Dhawan Space Centre spaceport located about 135 km east of Chennai is buzzing with activity once again as ISRO gears up for a rocket launch nearly after a gap of about six months.

The previous missions undertaken by the Bengaluru-headquartered space agency in 2024 were the successful launches of PSLV-C58/XPoSat mission on January 1 and GSLV-F14/INSAT-3DS mission on February 17.

The significance of the latest launch scheduled to take place from this spaceport at 9.19 am on August 16 is that it is the third and final developmental flight of the SSLV-D3. While the maiden mission of SSLV-D1/EOS-02 did not place the satellites into intended orbits in August 2022, the second developmental flight was successfully launched on February 10, 2023.

A short countdown is expected to commence the launch, ISRO sources told PTI on Thursday.

Earlier, ISRO had planned for the launch to take place on August 15 at 9.17 am but it was rescheduled to August 16 at 9.19 am with a one hour launch window. Scientists have not cited any reason for the change in the schedule.

A SSLV rocket is shorter at 34 metres tall (compared to PSLV rockets which are 44 metres tall) and are used to place satellites (mini, micro or nano satellites) that weigh up to 500 kg below 500 km of Low Earth Orbit.

The satellites carried in the SSLV-D3-EOS-08 mission weigh 175.5 kg and the launch vehicle comprises three solid propulsion stages and a liquid module as a terminal stage.

The key features of SSLV vehicles are -- it provides low-cost access to Space, offers low turn-around time and flexibility in accommodating multiple satellites, and demands minimal launch infrastructure.

A former ISRO scientist in a brief interaction with PTI had said that the cost of SSLV would be around 20-30 per cent lesser than the cost of PSLV missions, which use bigger rockets capable of deep space missions.

"Another point is that if someone plans to launch a satellite in a Low Earth Orbit, it will be possible to launch an SSLV rocket within two days of planning," he said indicating the flexibility on such SSLV rocket missions.

The scientist was also of the view that SSLV rockets are not only used for placing satellites in Low Earth Orbits but also in placing satellites in the Sun Synchronous Orbit (SSO), based on the demand of a customer.

The primary objectives of the SSLV-D03 mission include designing and developing a micro-satellite, creating payload instruments compatible with the micro satellite bus and incorporating new technologies for future operational satellites.

The SSLV rocket carries three payloads -- Electro Optical Infrared Payload (EOIR), which is designed for use in applications like satellite-based surveillance, disaster and environmental monitoring, fire detection, volcanic activity among others.

The second payload is the Global Navigation Satellite System-Reflectometry (GNSS-R), which would be used for ocean surface wind analysis, soil moisture assessment, cryosphere studies over the Himalayan region, flood and inland waterbody detection.

The final payload is the SiC UV Dosimeter which would monitor the UV irradiance at the viewport of the Crew Module in the Gaganyaan Mission and serve as a high-dose alarm sensor for gamma radiation.

Scientists have planned to place the satellite in a Circular Low Earth Orbit at an altitude of 475 km with an inclination of 37.4 degree. The satellite mission life is one year.

The EOS-08 mission also marks a significant advancement in satellite mainframe systems such as an Integrated Avionics System known as the Communication, Baseband, Storage and Positioning package which combines multiple functions into a single, efficient unit.

The satellite also includes a structural panel embedded with PCB, an embedded battery, a Micro-DGA (Dual Gimbal Antenna), a Micro-Phased Array Antenna and a flexible solar panel, each serving as a key component for onboard technology demonstration.