EOS-8 was put in orbit in the third and final developmental flight of the Small Satellite Launch Vehicle (SSLV)
In a significant development for future missions, the Indian Space Research Organisation (ISRO) successfully completed the Small Satellite Launch Vehicle (SSLV) project with the launch of the latest Earth Observation Satellite ‘EOS-08’ on Friday (August 16, 2024).
 
The Earth Observation Satellite (EOS-8) was launched in the third and final developmental flight of the SSLV from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh at 9.17 am (IST). The satellite was injected into its intended 475-km circular orbit 17 minutes later. "The rocket has placed the spacecraft in a very precise orbit as planned," ISRO Chairman S Somanath said.

The satellite, with a mass of about 175.5 kg, has a mission life of one year. ISRO is now working on transfer of technology of the SSLV to the industry to pave the way for future launches of small satellites using this cost-effective technology.
 
Prime Minister Narendra Modi described the successful launch as a “remarkable milestone”. He said the cost-effective SSLV would play an important role in future missions and encourage private industry.
 
“A remarkable milestone! Congratulations to our scientists and industry for this feat. It is a matter of immense joy that India now has a new launch vehicle. The cost-effective SSLV will play an important role in space missions and will also encourage private industry. My best wishes to @isro, @INSPACeIND, @NSIL_India and the entire space industry,” he said on social media platform X (formerly Twitter) in reply to a post by ISRO.

Three Payloads on EOS-8

 According to information provided by the Department of Space, the EOS-08 carries three payloads: Electro Optical Infrared Payload (EOIR), Global Navigation Satellite System-Reflectometry payload (GNSS-R), and 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 SiC UV Dosimeter monitors UV irradiance at the viewport of the Crew Module in the Gaganyaan Mission and serves as a high-dose alarm sensor for gamma radiation.
 
Key Features of EOS-8

 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. 
 
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.

The satellite employs a miniaturized design in its Antenna Pointing Mechanisms, capable of achieving a rotational speed of 6 degrees per second and maintaining a pointing accuracy of ±1 degree. The miniaturized phased array antenna further enhances communication capabilities, while the flexible solar panel incorporates a foldable solar panel substrate, GFRP tube, and CFRP honeycomb rigid end panel, offering improved power generation and structural integrity. A pyrolytic graphite sheet diffuser plate, known for its high thermal conductivity of 350 W/mK, reduces mass and finds application in various satellite functions.
 
The EOS-08 mission adopts a new method of integrating housekeeping panels using a hinge-based fixture, significantly reducing the duration of the Assembly, Integration, and Testing (AIT) phase.
 
Incorporating additional novel schemes, the EOS-08 mission improves satellite technology through X-band data transmission, utilizing pulse shaping and Frequency Compensated Modulation (FCM) for X-Band data transmitters. The satellite’s battery management system employs SSTCR-based charging and bus regulation, sequentially including or excluding strings at a frequency of 6 Hz.