The second developmental flight of the Small Satellite Launch Vehicle (SSLV), SSLV-D2, was successfully launched by the Indian Space Research Organisation (ISRO) from the first launch pad at Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota on February 10, 2023. The main objectives of the mission included the demonstration of the designed payload capability of SSLV in low earth orbit and the injection of the earth observation satellite (EOS), EOS-07, and two passenger satellites, Janus 1 and AzaadiSAT-2, into a 450 km circular orbit. The SSLV-D2 placed the above-mentioned satellites into their intended orbits.
The SSLV-D2
The SSLV-D2 can launch up to 500-kg satellites to low earth orbits on a ‘launch-on-demand’ basis. It provides low-cost access to space, offers low turn-around time, and flexibility in accommodating multiple satellites. The launch vehicle requires a minimal launch infrastructure and uses three solid stages followed by a liquid-fuel-based Velocity Trimming Module (VTM) to place satellites in orbit. It is 34-metre tall, with 2-metre diameter and has a lift-off mass of 120 tonne. The satellites were injected into close to 450 km circular orbit at an inclination of 37.2 degrees.
Significance of SSLV-D2
This launch was significant because the first developmental flight of the SSLV-D1 from SDSC had failed on August 7, 2022, due to excessive vibration, sensed by accelerometers during the second stage separation, making the on-board system ‘think’ that the sensors were faulty. Therefore, structural changes were made to the equipment bay, along with changes in the separation mechanism for stage 2, and logic changes for the on-board system.
About the Payload
The EOS-07 The EOS-07 is a 156.3-kg satellite, designed, developed, and realised by the ISRO. Its mission objective is to design and develop payload instruments compatible with microsatellite buses, and new technologies, required for future operational satellites. ISRO also aims to design and develop a microsatellite which can accommodate new technology payloads in a quick turn-around time. New experiments include mm-Wave Humidity Sounder and Spectrum Monitoring Payload.
Janus-1 The Janus-1 is a technology demonstrator satellite, built by the US-based Antaris, and its Indian partners, XDLINX and Ananth Technologies. Weighing about 10.2 kg, Janus 1 is a six-unit cube satellite with five payloads on board—two from Singapore, and one each from Kenya, Australia, and Indonesia. The entire satellite was built in a period of 10 months which has been less than half the time taken usually. It is a smart satellite mission based on the Antaris software platform.
Antaris and its Indian allies create a standardised satellite bus (the main structure of a satellite on which the payloads rest) on which multiple payloads can be attached like Lego blocks enabling companies to quickly and cheaply launch their payloads. Once launched, the operations are handled either by Antaris India group or the payload companies which are given access to their platform to control theirs.
Antaris aims to make satellite buses of different sizes for satellites weighing around 100 kg.
AzaadiSAT-2 The 8.7-kg satellite, AzaadiSAT-2, is a combined effort of about 750 girl students from across India, guided by Space Kidz India, Chennai. The satellite aims to demonstrate LoRa and amateur radio communication satellites, a sensor to measure radiation levels in space, and sensors to measure the health of the satellite such as temperature, reset count, and inertial data It also has some additional feature as compared to AzaadiSAT-1.
AzaadiSAT-2 is an expandable satellite. According to the founder and CEO of Space Kidz India, the eight-unit satellite consists of a spring mechanism-based external frame which would open up once the satellite is out in the orbit. After the frame opens up, the satellite would become four times its size. The external frame would host new cheaper type of solar panels to provide energy to the satellite. For sustaining longer durations in space energy is one of the challenges of the small satellites.
The satellite has also carried the G20 logo to space and the National Cadet Corps (NCC) song to celebrate 75 years of India’s independence. The idea of small size at the time of launch with a bigger power pack was opted as the satellite would easily fit in the launch vehicles, and start-ups also would spend less money.
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