Explained: ISRO’s EOS-08 by SSLV-D3

The Indian Space Research Organisation (ISRO) has successfully launched the EOS-08 Earth Observation Satellite using the Small Satellite Launch Vehicle (SSLV)-D3. This marks the third and final test flight of the SSLV, officially completing its development phase. The launch occurred from the Satish Dhawan Space Centre in Sriharikota on 16^th August 2024 at 9:17 am. Seventeen minutes after liftoff, the satellite was placed into a precise orbit 475 km above the Earth. “The third developmental flight of SSLV, the SSLV-D3 with the EOS-08 satellite, has been accomplished. The rocket has placed the spacecraft in a very precise orbit as planned. I find that there are no deviations in the injection conditions. The current indication is that everything is perfect,” ISRO Chairman S Somanath said after the successful launch.

More About EOS- 08 satellite

EOS-08 is a first-of-its-kind mission built on a standard ISRO’s Microsat/IMS-1 bus with advanced payloads for observation in the IR range, a novel GNSS-R Payload, and a SiC UV dosimeter.

The satellite carries a host of new technology developments in satellite mainframe systems like an Integrated Avionics system – Communication, Baseband, Storage and Positioning (CBSP) Package, Structural panel embedded with PCB, embedded battery, Micro-DGA (Dual Gimbal Antenna), M-PAA (Phased array antenna) and Flexible solar panel & Nano star sensor etc for onboard Technology Demonstration. The satellite is slated for launch by the SSLV-D3.

Payloads of EOS- 08

The satellite carries three payloads: Electro Optical Infrared Payload (EOIR), SAC, Global Navigation Satellite System- Reflectometry payload (GNSS-R), SAC and SiC UV Dosimeter, and LEOS.

The EOIR payload is to image in the Mid-Wave IR (MIR) band and long-wave IR (LWIR) band during day and night for various applications like Satellite-based surveillance, Disaster Monitoring, Environmental Monitoring, Fire Detection, Volcanic activities, and Industrial and power plant disaster.
GNSS-R payload is to demonstrate the capability of using GNSS-R-based remote sensing to derive applications like Ocean Surface Winds, Soil moisture, Cryosphere applications over the Himalayan Region, Flood detection, In-land water body detection, etc.
The SiC UV Dosimeter is to monitor the UV irradiance at the View Port of the Crew Module in Gaganyaan Mission and to be used as a high-dose alarm sensor for UV Radiation.

Objectives of the Satellite Mission

Mr. Somanath said that with the success of the SSLV-D3, ISRO has declared the development process of SSLV completed. “We are in the process of transfer of the technology of the SSLV to the industry and for serial production and launch of SSLV, this is a great beginning,” Mr. Somanath said.

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. Also onboard was the SR-0 DEMOSAT developed by Space Kidz India which was also placed in the intended orbit.

The SSLV is capable of launching Mini, Micro, or Nanosatellites (10 to 500kg mass) into a 500 km planar orbit. SSLV is a three-stage launch vehicle with all solid propulsion stages and a liquid propulsion-based Velocity Trimming Module (VTM) as a terminal stage.

According to ISRO, the design drivers of SSLV are low cost, low turn-around time, flexibility in accommodating multiple satellites, launch-on-demand feasibility, minimal launch infrastructure requirements, etc.

In a nutshell, the mission comprises the following major points:

Development of micro-satellites.
Integration of Advanced Payload Instruments.
Implementation of new Technologies for Future Operations.
Payload instruments compatible with microsatellite bus and with new technologies that are required for future operational satellites.
A microsatellite accommodating new mainframe technologies like integrated avionics package, structural panel with embedded PCB/battery, flexible Solar Panel, and m-DGA.

Small Satellite Launch Vehicle (SSLV)- D3

The Small Satellite Launch Vehicle (SSLV) is capable of launching Mini, Micro, or Nanosatellites (10 to 500kg mass) into a 500 km planar orbit. SSLV is a three-stage launch vehicle with all solid propulsion stages and a liquid propulsion-based Velocity Trimming Module (VTM) as a terminal stage.

Design drivers of SSLV are Low cost, low turn-around time, flexibility in accommodating multiple satellites, launch-on-demand feasibility, minimal launch infrastructure requirements, etc.

SSLV-D3 is the third developmental flight of SSLV.

The objectives of the SSLV- D3 were:

Demonstration of repeatable flight performance of SSLV Vehicle Systems.
Injection of EOS-08 satellite and SR-0 DEMOSAT passenger satellite into 475 km circular orbit.

SSLV-D3 Vehicle characteristics:

Vehicle Height: 34 m

Vehicle Diameter: 2 m

Lift off Mass: ~119 t

Vehicle Configuration: SS1 + SS2 + SS3 + VTM

SSLV-D3 Mission Specifications:

Altitude (km): 475 km

Inclination (deg): 37.4

Launch Pad: FLP

Launch Azimuth (deg): 135

New Technologies- What is in the future of ISRO?

Communication, Baseband, Storage, and Positioning (CBSP) is a single package with cold redundant systems designed using COTS components and evaluation boards performing Communication, Baseband, Storage, and satellite positioning functions supporting storage of 400 Gb.
The RFS package consists of LNAs, S-Band and X-Band filters, Switches, and Solid State Power amplifiers.
Multi-functional Structural Panel with Embedded Battery and Power Electronics Card Enables mass and volume savings with improved functionality.
Hinge-Based Integration Fixture: A New Method of Integration of Housekeeping panels seamlessly using hinge-based fixture was adopted for the mission to reduce the Assembly, Integration, and Testing time of the satellite.
Micro-Dual Gimbal Antenna (mDGA) having rotational speed of 6°/s and pointing accuracy of ±1°.
Micro-Dual Gimbal Antenna (mDGA) having rotational speed of 6°/s and pointing accuracy of ±1°.
Pyro-lytic Graphite Sheet Diffuser plate: Higher thermal conductivity of 350W/mK with reduced mass which can be used in multiple applications.

New novel schemes in mainframe technologies by ISRO

X-band Data Transmission: Pulse shaping and FCM for X-band data transmitters.
Battery: SSTCR-based battery charging / bus regulation by sequentially including/excluding strings (freq. 6Hz).
TM-TC System: Dual mode for TM-TC system, Miniaturized microstrip filters for Data. ü Indigenized process of Solar cell fabrication.
Sensors: Use of Nano-Star Sensor for Microsat Application.
Inertial System: Vibration isolations for Reaction Wheels.
Interfaces: Single Antenna interface for TTC and SPS application.
Thermal Management: Novel materials for Thermal management of antennae like Germanium Black Kapton, and STAMET (Si-Al Alloy) Black Kapton were used.
Mission Management: Auto Launch Pad initialization feature. ISRO’s IMS-1 Bus system capabilities are considerably improved with the induction of various new technologies in terms of enhanced power generation (16%), more payload mass (33%), increased data download rate (5 times data rate & FACM mode), and more data storage (12 times) in EOS-08 Mission.

Future of India’s Space Exploration

India’s space exploration future looks promising, as the country has been making significant progress in the field in recent years. The Indian Space Research Organisation (ISRO) has been actively involved in various space missions and has set ambitious goals for the future.

Human Spaceflight Program: ISRO is working towards sending Indian astronauts into space. The Gaganyaan mission is India’s first manned space mission, which aims to carry a crew of two or three astronauts into a low Earth orbit. The program is scheduled for 2022 and will make India the fourth country to send humans to space.
Mars Mission: Building on the success of the Mars Orbiter Mission (Mangalyaan) in 2014, which made India the first country to reach Mars on its maiden attempt, ISRO has plans for future Mars missions. These missions will focus on studying the Martian atmosphere, climate, and geology in greater detail.
Interplanetary Missions: ISRO has expressed interest in exploring other planets and celestial bodies. There have been discussions about potential missions to Venus, Jupiter, and even asteroids. These missions would contribute to our understanding of the solar system and expand India’s footprint in deep space exploration.
Satellite Launches and Communication: India has established itself as a reliable and cost-effective option for satellite launches. ISRO’s Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV) are renowned for their capabilities. India will continue to launch satellites for various purposes, including communication, weather monitoring, earth observation, and scientific research.
International Collaboration: India has been actively collaborating with other countries and space agencies on various space missions. Collaborative projects provide an opportunity to share resources, knowledge, and technology, enabling India to undertake more ambitious missions and advance its space exploration capabilities.
Space Industry Development: India is also focusing on developing its space industry. Initiatives such as the Space Activities Bill, which aims to encourage private sector participation in space activities, and the establishment of the Indian National Space Promotion and Authorization Center (IN-SPACe), demonstrate India’s commitment to fostering a thriving space industry.

Overall, India’s space exploration future is characterized by its determination to expand its capabilities, explore new frontiers, and contribute to scientific knowledge. With ambitious missions, technological advancements, and a growing space industry, India is poised to make significant contributions to the global space community in the coming years.

Disclaimer: the above-mentioned article is based on information from the Press Information Bureau of India Brochure, and the Hindu.

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Explained: ISRO’s EOS-08 by SSLV-D3

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