It was a moment of pride for the Indian Space Research Organisation (ISRO) when the second developmental flight of the Small Satellite Launch Vehicle (SSLV) successfully placed three satellites, including earth observation satellite EOS-07, in intended orbits this morning.
More so because the first launch of SSLV on August 7, 2022, had failed in part due to the rocket's orbit being off and it straying from its intended trajectory. However, all that was history with Friday's success.
The highlight of the SSLV is that it provides low-cost access to space, offers low turn-around time and flexibility in accommodating multiple satellites, and requires minimal launch infrastructure.
Friday's launch will put the EOS-07 Earth observation satellite, together with the two co-passenger satellites, Janus-1 and AzaadiSat2, created by start-ups, in a 450-km round Low Earth orbit.
It is a 15-minute flight to Low Earth Orbit with three payloads weighing over 350 kilograms. Approximately 13 minutes following the launch, the three-stage rocket launched EOS-07, and almost 1.6 minutes later, two accompanying satellites into orbit.
Interestingly, the SSLV has been created to take over the responsibility of the Polar Satellite Launch Vehicle (PSLV) and provide services to the smaller satellite launch sector.
The launch came after the conclusion of a six-and-a-half-hour countdown when the 34-meter tall rocket from ISRO lifted off successfully.
Students watch the launch of Small Satellite Launch Vehicle SSLV-D2 at Satish Dhawan Space Station in Sriharikota on Friday | PTI
"SSLV, developed by ISRO, offers the capability of lifting up to 500 kg satellites to low Earth orbits on a 'launch-on-demand' basis. It provides cost-effective access to space, has a quick turnaround time (around 72 Hours), and can accommodate numerous satellites with minimal launch infrastructure. Earth Observation Satellite, EOS-07 is a 156.3 kg satellite created by the Indian space agency,” explained Girish Linganna, an aerospace and defence expert.
The experiments that are being conducted recently involve the mm-Wave Humidity Sounder and the Spectrum Monitoring Payload. Janus-1 weighs 10.2 kg, whereas the AzaadiSAT-2, which was a collective effort of around 750 female students from various parts of India under the guidance of Space Kidz India in Chennai, weighs 8.7 kg.
Linganna says that an analysis of the breakdown of SSLV-D1 in August 2022 by ISRO discovered that the mission failed when the upper part of the rocket-propelled the satellite into a highly elliptical and unstable trajectory due to the lack of sufficient velocity.
"The satellites that were on the SSLV-D1 rocket at the time of its August launch were put into a very elongated orbit due to a lack of required velocity, after which they rapidly became unusable. Despite the first three stages of the rocket working properly, this occurred. ISRO's fault assessment that was just released revealed that when the second stage was separating, there were vibrations that were higher in intensity and longer in duration than what had been anticipated or tested for on the ground. These vibrations were recorded by the six accelerometers that were on the vehicle, and the readings are used for adjusting the direction of the rocket during the mission,” added Linganna.
As per the recommendations to guarantee that this issue does not arise again, the report said that, for the second trial flight, the system for detaching the second stage be altered to minimize vibrations.
Additionally, it indicates a shift in the reasoning of the system to address such temporary happenings – if multiple sensors are found to be damaged, readings will be observed for a longer period before going into rescue mode. In case of the failure of sensors, the system will be able to navigate using NaVIC (Indian Regional Navigation Satellite System) data.
As per ISRO the EOS-07, weighing 156.3kg, has a mission life of one year. The EOS-07 mission objective was to design and develop payload instruments compatible with a microsatellite bus and new technologies that are required for future operational satellites and to design and develop a microsatellite accommodating new technology payloads in a quick turn-around time.
