The Solar Polarization and Directivity X-Ray Experiment (PADRE) is a groundbreaking NASA CubeSat mission dedicated to exploring the mysteries of the Sun. As a 12U solar spinner CubeSat, PADRE will investigate the polarization and directivity of hard X-rays (HXRs) emitted during solar flares, providing critical insights into the behavior and distribution of high-energy electrons in the solar atmosphere. Built on a cutting-edge CubeSat platform provided by EnduroSat, PADRE combines advanced instrumentation with a robust spacecraft design to tackle significant scientific challenges, offering a cost-effective yet powerful platform for next-generation solar physics research.
Collaborative Effort
PADRE is a global collaboration between institutions leading in solar and space science, including the Space Sciences Laboratory (SSL) at UC Berkeley, NASA Goddard Space Flight Center (GSFC), Southwest Research Institute (SWRI), University of Applied Sciences and Arts Northwestern Switzerland (FHNW), CEA-Saclay, and EnduroSat, the spacecraft provider. SSL leads the project, integrating contributions from each partner to deliver groundbreaking solar science.
Science Goals
PADRE’s mission is designed to revolutionize our understanding of solar flare physics through two key objectives:
- X-ray Polarization Measurements: The SHARP instrument will measure the degree of polarization of HXRs, revealing whether the flare-accelerated electrons are strongly beamed or isotropic.
- X-ray Directivity Studies: The MeDDEA system will quantify the anisotropy of HXRs by cross-calibrating detectors observing the same solar flare from multiple perspectives.
These observations will provide unique diagnostics of particle acceleration and energy release processes, refining current solar flare models.
Innovative Design
PADRE’s compact 12U CubeSat design incorporates:
- A solar-spinning spacecraft configuration for stable and continuous Sun-facing observations.
- The SHARP polarimeter to measure hard X-ray polarization with high precision.
- The MeDDEA detector system to perform directivity measurements.
- Advanced high-voltage systems supplied by SWRI to power state-of-the-art photon-counting detectors.
Global Impact
PADRE’s international collaboration demonstrates the power of combining expertise and innovation. The mission will answer fundamental questions about solar flare dynamics while showcasing the capability of CubeSat technology for high-impact space science.