ISRO Set For PSLV Launch Of Two Singaporean Satellites And Seven Indian Payloads For In-Orbit Scientific Experiments

An Indian Space Research Organisation (ISRO) space launch is always an anticipated national event. The next one to look forward to is the launch of the polar satellite launch vehicle (PSLV) this weekend.

The PSLV-C55/TeLEOS-2 mission launch is scheduled for 22 April 2023 at 2.19 pm (8.49 am UTC) from the Satish Dhawan Space Centre-Sriharikota Range (SDSC-SHAR), ISRO revealed on Thursday (20 April).

As an earlier Swarajya report indicated, this PSLV launch will be a dedicated commercial mission that will be fulfilled by New Space India Limited (NSIL), and will feature a Singaporean Earth-observation satellite called TeLEOS-02 (referred to in the ISRO mission name) as the primary payload.

This is the successor satellite to TeLEOS-01, Singapore’s first-ever commercial Earth-observation satellite, launched back in December 2015 by a PSLV rocket (PSLV-C29/TeLEOS-1 mission).

ISRO said on Thursday that TeLEOS-02 will also be accompanied by a co-passenger satellite in “Lumelite-4.”

Further, payloads from ISRO or the Department of Space, Bellatrix, Dhruva Space, and Indian Institute of Astrophysics will fly alongside the two Singaporean satellites.

This will be the fifty-seventh flight of the PSLV and sixteenth mission using the PSLV Core Alone configuration (PSLV-CA).

Singaporean Satellites

TeLEOS-02 is designed and developed by Singapore’s ST Engineering (specifically ST Electronics), just as was TeLEOS-01, in partnership with the Singapore government’s Defence Science and Technology Agency.

The development of TeLEOS-02, Singapore's first synthetic aperture radar (SAR)-based imaging satellite, commenced in 2017.

The 741 kg satellite will be capable of providing 1 m resolution data. It will be equipped with a 500 GB onboard recorder for recording the data captured and a high-speed 800 Mbps downlink.

“With the TeLEOS-2, round-the-clock, all weather satellite imagery would now be possible,” ST Engineering had said on Facebook in 2018. “The imagery could be used for hotspot monitoring and haze management, air crash search and rescue operations and much more,” it added.

“Once deployed and operational, it will be used to support the satellite imagery requirements of various agencies within the Government of Singapore,” ISRO said.

The co-passenger satellite Lumelite-4 is developed jointly by the Institute for Infocomm Research (I2R) of the Agency for Science, Technology, and Research (A*STAR) and the Satellite Technology and Research Centre (STAR) of the National University of Singapore.

According to ISRO, the 16 kg technology demonstration nanosatellite is an “advanced 12U satellite developed for the technological demonstration of the High-Performance Space-borne VHF Data Exchange System (VDES).”

The VDES communication payload “aims to augment Singapore’s e-navigation maritime safety and benefit the global shipping community,” India’s space agency said.

Both TeLEOS-02 and Lumelite-4 will be launched into an eastern low-inclination orbit.

Indian Payloads

The PSLV is a four-stage rocket. The first three stages do their work and separate from the vehicle to fall back into the ocean.

The fourth stage, however, ends up in space as space junk or debris after satellite separation.

ISRO is trying to find use for this spent fourth stage through a new platform.

The agency’s plan is to double up this spent fourth stage of the PSLV rocket as an orbital platform to conduct scientific experiments with payloads, which, unlike the satellites, don’t separate from the rocket.

This feature or platform is called the PSLV Orbital Experimental Module (POEM).

It was put to work before, on 30 June 2022, as part of the PSLV-C53 mission.

On the upcoming PSLV-C55 mission, it will be put to work a third time, according to ISRO.

It will further demonstrate the use of the launch vehicle’s spent upper stage as a stabilised platform for scientific payloads.

Here is where the seven experimental payloads from the Indian government, leading Indian scientific institutes, and two private space players will find use.

The non-separating POEM-2 payloads are the ARIS-2 and PiLOT experiments from the Indian Institute of Space Science and Technology, the ARKA200 electric propulsion system from Bellatrix, the Starberry sense payload from the Indian Institute of Astrophysics, and the DSOL, DSOD-3U, and DSOD-6U units from Dhruva Space.

The payloads will be powered ON by a command, after all the satellites are separated, after which they will get to work.

The spent fourth stage and a deployable solar panel make up the orbital platform configuration. The expected period of operation is one month.

Launch Preparations

Launch campaign activities for the PSLV-C55/TeLEOS-02 mission commenced on 10 February this year at Sriharikota.

ISRO adopted the new ‘Integrate, Transfer, and Launch’ (ITL) route using the PSLV Integration Facility.

According to a report in The Times of India, it is the first-ever rocket to have been integrated at the new integration facility.

They went with a new way of integrating the rocket this time around with the aim of cutting down time in the assembly process, the report said.

The previous PSLV mission, PSLV-C54/EOS-06, took place on 26 November 2022.

It involved placing in orbit the Earth-observation satellite Oceansat-3, along with eight other co-passenger satellites, most notably the ISRO Nano Satellite-2 for Bhutan (INS-2B) and three satellites (Anand and Thybolt 1 and 2) by two Indian space technology companies Pixxel and Dhruva Space.

The next PSLV mission, PSLV-C56, is expected to see the launch of the first Indian space mission to study the Sun, called Aditya-L1.