Relativistic Proton Spectrometer (RPS)
Principal Investigator: Joseph Mazur, The Aerospace Corporation
The RPS instrument focuses on the inner radiation belt, an area that houses some of the highest energy protons in Earth's magnetic environment. These protons move fast enough that no shielding can stop them. Thus, they can easily penetrate inside a spacecraft, where they can harm electronics or astronauts. To study these particles, the RPS instrument measures the protons' energy and how their intensity varies over time. This will help scientists understand how the inner belt changes in response to solar activity.