ISRO will use an XL variant of the PSLV to place the Aditya-L1 spacecraft in a low earth orbit. Photo: isro.gov.in

Scientists at the Space Physics Laboratory (SPL) under the Vikram Sarabhai Space Centre (VSSC) here are getting ready to unravel the secrets of the solar wind as the Aditya-L1 mission, meant to study the sun, lifts off in September.

The Plasma Analyser Package for Aditya (PAPA) payload aboard Aditya-L1, one of seven scientific payloads aboard the challenging mission, was developed by the SPL to gain deeper insights into the phenomenon of the ‘solar wind,’ as the constant stream of charged particles from the sun is called.

S. Somanath, Chairman, Indian Space Research Organisation (ISRO), said on Saturday that the mission would lift off from Sriharikota in the first week of September.

Energy of electrons

The SPL’s PAPA payload will study the composition of the solar wind, a senior ISRO official said. “It will look at the energy of electrons and the energy and mass of protons and ions in it. The study will also cover the angular variations,” the official said.

For the SPL, the Aditya-L1 mission is yet another big occasion, coming close on the heels of the Chandrayaan-3 lunar mission on which it had two important scientific payloads. ISRO describes Aditya-L1 as the ‘‘first space-based Indian mission to study the sun’‘ from a halo orbit around the Lagrangian point 1 (L1) of the sun-earth system.

Weighing roughly 8 kg, PAPA shares space on the Aditya-L1 spacecraft with six other payloads developed by sister ISRO units and other scientific establishments collaborating with ISRO. According to ISRO, the payloads are designed ‘‘to study the chromosphere, the photosphere and the outermost layers of the sun using electromagnetic and particle detectors.’‘

ISRO will use an XL variant of the Polar Satellite Launch Vehicle (PSLV) to place the Aditya-L1 spacecraft in a low earth orbit. Mr. Somanath said in Thiruvananthapuram on Saturday that the spacecraft had been integrated with the launch vehicle at Sriharikota. Once launched, it will take 125 days to travel to its destination at L1.

On board the Chandrayaan-3 mission’s Vikram lander which soft-landed on the moon on August 23, the SPL had two payloads; the Chandra’s Surface Thermophysical Experiment (ChaSTE) and the Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere (RAMBHA).