Science questions are the motivation and justification for developing new instrumentation. The formal process requires a translation from these science questions into quantitative science requirements, from which requirements on the instrument performance can be derived. Simulation of the observables, either based on existing observation or modelling, and including the major uncertainty sources such as noises, are often required to constrain achievable performance requirements. This provides a baseline for starting designing an instrument able to match the performance needs.

This talk will illustrate this process, using the Auroral Polarization Explorer (APEX) instrument concept as an example. APEX is a sounding rocket instrument developed by a team of student from Graz (ASTG, TU Graz & KFU) and supervised by the IWF. It has been selected by the ESA/DLR/SSC REXUS program in December 2024, and will be launched in March/April 2026 on a sub-orbital rocket. The instrument aims at measuring the polarization of the auroral and airglow emissions from above the atmosphere. The main science motivation will be described, defining the science requirements for the instrument.  From there, an overview of the observation simulation will be presented, which enabled to derive lower-level performance requirements. With this input and the external constraints from the REXUS platform, the design of the instrument will be discussed.

recording: www.youtube.com/watch