Checkout System and Payload Simulator for PAPA Payload in Aditya-L1 Mission

Plasma Analyser Package for Aditya - L1 (PAPA) mission aims at studying the composition of solar wind and its energy distributions. Parallel to PAPA payload development, a ground-based checkout system was designed and developed for all ground level testing and calibration of payload before integrating it to satellite. Due to parallel development of payload and checkout system, all the requirements of checkout system were not frozen at the beginning; Due to this there was a need for the developed checkout system to be modular and re-configurable with minimum development time. Checkout system was designed and developed using PCI eXtensions for Instrumentation (PXIe) platform and LabVIEW software. A PXIe platform was chosen since it provides the required modularity of design and portability. LabVIEW software is chosen for ease of development and re-configurability. Queued event-based producer/consumer design pattern was used to design and implement the checkout software. PAPA payload needs high level of vacuum for payload operations due to its internal bias voltages in the range of kilo volts. Therefore, the checkout system needs to monitor the vacuum level and command the payload accordingly to avoid damaging payload while testing. To cater to this and other special requirements extensive error handling algorithms, various interlocks, and vacuum monitoring interlock are implemented in the checkout software. A PAPA payload simulator was designed and developed to test and evaluate the adequacy of the checkout system and to correct and optimize the checkout software before it is used for testing PAPA payload. PAPA payload was successfully tested and calibrated using the developed checkout system. This paper describes the design and features of the checkout system and PAPA payload simulator.