TAG: GS 3: SCIENCE AND TECHNOLOGY
THE CONTEXT: The Indian Space Research Organisation (ISRO) recently announced that its latest Earth Observation Satellite, EOS-08 is slated for launch by the Small Satellite Launch Vehicle (SSLV)-D3.
EXPLANATION:
EOS-08 Mission
- The main goals of the EOS-08 mission are to design and develop a microsatellite, as well as to incorporate new technologies needed for operational satellites in the future and create payload instruments that are compatible with the microsatellite bus.
- The spacecraft mission configuration is set to operate in a Circular Low Earth Orbit (LEO).
- It is set 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 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.
Payloads
- Built on the Microsat/IMS-1 bus, 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, day and night.
- It has applications such as satellite-based surveillance, disaster management, environmental monitoring, fire detection, volcanic activity monitoring, industrial power plant disaster management and more
- The GNSS-R payload demonstrates the potential of using GNSS-R based remote sensing for applications such as sea surface wind observations, terrestrial climate studies, studies of the cryosphere over the Himalayan region, flood a identification and identification of water tables.
- Meanwhile, the SiC UV Dosimeter monitors UV radiation in the viewport of the Crew Module of the Gayanyayan mission and acts as a high-dose alarm sensor for gamma radiation.
Antenna mechanism
- The satellite employs a miniaturized design in its Antenna Pointing Mechanisms.
- It is 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.
- Furthermore, 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.
Innovative Satellite Technology
- 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.
- The TM-TC system supports dual modes, including CDMA and Direct PSK, with miniaturized microstrip filters tailored for data and TM-TC applications.
- The mission’s indigenization effort is evident in its solar cell fabrication processes and the use of a Nano-Star Sensor for Microsat Applications.
- Additionally, the inertial system benefits from reaction wheel isolators that attenuate vibrations and a single antenna interface is utilized for TTC and SPS applications.
- Thermal management is enhanced using materials such as AFE BGA, Kintex FPGA, Germanium Black Kapton, and STAMET (Si-Al Alloy) Black Kapton to handle the thermal properties of COTS components.
- The mission also incorporates an auto-launch pad initialization feature, further demonstrating its commitment to innovative mission management.
