Plasma Analyser Package for Aditya (PAPA) onboard Aditya-L1 spacecraft is an energy and mass analyser payload meant for monitoring the solar wind electrons flux and ions flux, with two sensors viz. Solar Wind Electron Energy Probe (SWEEP) and Solar Wind Ion Composition Analyser (SWICAR) respectively.

In order to check the in-orbit health status, the payload was switched ON for the first time during the cruise phase on November 8, 2023 at 10 hours, without enabling the high voltage (5 kV). The payload ON was tested with both main and redundant DC-DC converters. Throughout the cruise phase, the electronics of PAPA payload has been continuously kept ON and the 127 data sets received were analysed at the payload operation centre at Space Physics Laboratory, VSSC. The payload health parameters are verified with design parameters and are well within the expected limits, heralding payload's good health.

Since the high voltage is OFF, null count is observed for both SWEEP and SWICAR sensors. Voltage levels of sub-systems are steady. The device switch on current is less than 140 mA throughout the operations. The temperatures of the sensors are steady within 2°C (30 to 32°C for SWEEP and 33 to 35°C for SWICAR) over several hours of continuous operations. During spacecraft orientations, the detector temperatures varied between 20 to 34°C over a period of 2 hours. However, all the above observed variations are well within the prescribed limit of 10°C to 40°C for the payload operations.

Switching ON of high voltage (5 kV) for the first time is planned on December 11, 2023 and it will be carried out in incremental steps with due monitoring of all parameters. The detection of electrons, ions and their flux can be done after the high voltage power supply is enabled. The study of electrons & ions flux and their energies will enhance our understanding of solar dynamics, space weather events and their potential impacts on spacecrafts and solar system.