With the Indian Space Research Organisation (ISRO) planning to keep the fourth and final stage of the Polar Satellite Launch Vehicle (PSLV) ‘alive’ in space as a useful ‘orbital platform’, the rocket — popularly dubbed ISRO’s trusted workhorse — is getting added features.
Set for lift-off this month with the Microsat-R payload, the upcoming PSLV-C44 mission will see a new variant of the PSLV in use.
This variant, tagged PSLV-DL, will be the first to sport two strap-on boosters for providing added thrust.
Lithium-ion cells
Its final and fourth stage — PS4 — will be equipped with lithium-ion batteries, but no solar panels.
An in-house technology, the lithium-ion cells are critical to keep the spent stage in orbit. Solar panels will be added, in all likelihood, in the next mission, VSSC director S. Somanath says.
The ISRO had hit upon the idea of transforming the expendable fourth stage into a makeshift satellite to reduce space debris.
In normal scenario, the initial stages of the rocket, once they detach, drop back into the sea.
‘Recycling’
However, stage four, after releasing the payload, wanders around in space as junk.
If the ISRO plan is successful, the spent stage will be automatically ‘recycled’ into a valuable platform for space-based experiments.
The VSSC director said that the ISRO would perfect the technology with tests spread over multiple missions.
“We are doing it incrementally. In the PSLV-C44 mission, the platform will be demonstrated. “We have to show that the PS4 stage can be kept ‘alive’ for more than one orbit. After the regular payloads are injected into their orbits, we will shift the spent stage to another orbit and keep it there and demonstrate that it is live,” he said.
On the C44 mission, the ISRO will also test the downloading of data from the stage to the ground station. In subsequent missions, the space agency will carry out experiments using the platform.
A number of experiments are under consideration, though nothing has been finalised. The PSLV, which first flew successfully in 1994, has evolved over the years.
Of the current configurations in use, PSLV-XL employs six strap-on boosters while the ‘core alone’ has none.
Twin boosters
On the new ‘DL’ type, the twin boosters will burn at lift-off to give additional thrust to the rocket. The boosters will carry 12 tonnes of propellant.
In all other respects, the 44-metre-tall PSLV will have standard features.
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