Sriharikota: The Indian Space Research Organization (ISRO) on Saturday successfully placed two Singaporean satellites – Teleos-2 (a synthetic aperture radar satellite) and Lumilite-4 (a technology demonstration nano-satellite) into their desired orbits. A Polar Satellite Launch Vehicle (PSLV-C55), which carried these satellites, also carried scientific experiments with seven payloads attached to its PS4 upper stage.
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The rocket was launched from the first launch pad of the Satish Dhawan Space Center in Sriharikota at 2.19 pm. This was the 57th flight of PSLV. It was also the 16th flight of the PSLV with the CA (core-alone) variant, which is the lightest version of the launch vehicle as it has only four core stages and no strap-on boosters to provide additional thrust.
About 19 minutes after lift-off, PSLV-C55 placed the 741 kg TELYOS-2 into an orbit of 586 km. Fifty seconds later, the rocket also placed the 16 kg Lumilite-4 in the desired orbit.
About two minutes after the separation of the last satellite, the PSLV upper stage underwent deactivation (a chemical process) with mixed oxides of nitrogen (MON), followed by mono methyl hydrazine (MMH) – the propellant that powers the PSLV upper stage. provides. The operation was to reduce compression in the tanks to prevent an explosion. Given that it will be exposed to high temperatures, the fuel may expand and explode.
After this process, the PS4 upper stage of the rocket with the payload attached to it is transformed into an orbital platform (PSLV Orbital Experimental Module-2 or POEM-2) for conducting scientific experiments in orbit. Seven non-separable payloads were mounted on the Multi-Satellite Adapter (MSA).
ISRO Chairman S Somnath said that PSLV has once again proved its reliability. “The upper stage of the rocket is going to write a summer poem. Seven payloads are mounted on top of the upper stage. If all goes well, it will work for the next one month. This is the first time that we are putting solar panels in the PS4. We will update about the performance of POEM through our social media handles.”
ISRO officials said that the payload was operated by a command after all the satellites were separated. The stage consisted of a solar panel mounted around the PS4 tank which was deployed via a ground command after the stage was confirmed to have achieved stabilization.
The platform ensured that the deployed solar panel was pointed towards the sun, using an appropriate sun pointing mode to maximize its power generation efficiency. The payload and avionic package were powered based on their requirements. During this part of the mission, the platform remained in the same orbit achieved at the end of the PS4 tank inactivation after the primary mission.
This is the third time the PS4 has been used as a platform for experiments following the separation of the satellites.
Poem – 2
POEM-2 carries seven experimental non-detachable payloads. They include Pilot (PSLV in Orbital OBC & Thermals), an OBC package from IIST; ARIS-2 (Advanced Retardation Potential Analyzer for Ionospheric Studies) experiment from IIST; Bellatrix’s HET-based ARKA200 electric propulsion system; DSOD-3U and DSOD-6U deployer units as well as DSOL-transceivers in the S- and X-bands from Dhruva Space and the Starberry Sense payload from the Indian Institute of Astrophysics (IAP).
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Developed under a partnership between DSTA (representing the Government of Singapore) and ST Engineering, TLEOS-2 will be used to meet the satellite imagery needs of various agencies of the Government of Singapore. TeLEOS-2 carries a Synthetic Aperture Radar (SAR) payload. TeLEOS-2 will be able to provide day and night coverage in all weather conditions. It is capable of imaging at 1m absolute-polarimetric resolution.
Lumelite-4 is co-developed by the Infocomm Research Institute (I2R) of A*STAR and the Satellite Technology and Research Center (STAR) of the National University of Singapore. Lumilite-4 is an advanced 12U satellite developed for technical demonstration of a high-performance space-borne VHF Data Exchange System (VDES). Using the VDES communication payload developed by I2R and STAR’s scalable satellite bus platform, it aims to enhance Singapore’s e-navigation maritime safety and benefit the global shipping community.