The Relativistic Electron-Proton Telescope (REPT) Investigation: Design, Operational Properties, and Science Highlights

Abstract

The Relativistic Electron-Proton Telescope (REPT) instruments were designed to measure ∼2 to >18 MeV electrons and ∼18 to > 115 MeV protons as part of the science payloads onboard the dual Radiation Belt Storm Probes (RBSP) spacecraft. The REPT instruments were turned on and configured in their science acquisition modes about 2 days after the RBSP launch on 30 August 2012. The REPT-A and REPT-B instruments both operated flawlessly until mission cessation in 2019. This paper reviews briefly the REPT instrument designs, their operational performance, relevant mode changes and trending over the course of the mission, as well as pertinent background effects (and recommended corrections). A substantial part of this paper highlights discoveries and significant advancement of our understanding of physical-processes obtained using REPT data. We do this for energetic electrons primarily in the outer Van Allen belt and for energetic protons in the inner Van Allen zone. The review also describes several ways in which REPT data were employed for important space weather applications. The paper concludes with assessments of ways that REPT data might further be exploited to continue to advance radiation belt studies. The paper also discusses the pressing and critical need for the operational continuation of REPT-like measurements both for science and for space situational awareness.

Electron Flux Variability and Ultra‐Low Frequency Wave Activity in the Outer Radiation Belt Under the Influence of Interplanetary Coronal Mass Ejections and High‐Speed Solar Wind Streams: A Statistical Analysis From the Van Allen Probes Era

“…This work uses 2.10 MeV spin‐averaged data from the Relativistic Electron Proton Telescope (REPT) (Baker et al., 2013, 2021). The instrument is part of the Radiation Belt Storm Probes‐Energetic Particle Composition and Thermal Plasma (Spence et al., 2013).…”

“…They have practically the same orbit with an inclination of approximately 10° and are highly elliptical, with a perigee of 1.1 Earth radii (R E ) and apogee of ∼5.8 R E (Kessel et al, 2012;Mauk et al, 2013). This work uses 2.10 MeV spin-averaged data from the Relativistic Electron Proton Telescope (REPT) (Baker et al, 2013(Baker et al, , 2021. The instrument is part of the Radiation Belt Storm Probes-Energetic Particle Composition and Thermal Plasma (Spence et al, 2013).…”

Relativistic Electron Enhancements Through Successive Dipolarizations During a CIR‐Driven Storm

“…We employ the measurements from RBSP spacecraft (Mauk et al, 2013). We use RBSP data including the spin-averaged differential electron flux from Magnetic Electron Ion Spectrometer (MagEIS; Blake et al, 2013), Relativistic Electron-Proton Telescope (REPT; Baker et al, 2013Baker et al, , 2021, Helium Oxygen Proton Electron (HOPE) mass spectrometer (Funsten et al, 2013), the magnetic field from Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS; Kletzing et al, 2013) and the electric field from Electric Field and Wave instrument (Wygant et al, 2013). We convert the electron fluxes (33-1730 keV) into the PSD (Chen et al, 2005).…”

Achievements and Lessons Learned From Successful Small Satellite Missions for Space Weather‐Oriented Research

“…In a series of publications, by not only the students who enjoyed early access to CSSWE data but also now broadly by community members, our understanding of the loss and lifetimes of relativistic electrons in Earth's magnetosphere has grown considerably clearer (e.g., Blum et al., 2013; Li, Schiller, et al., 2013; Zhang et al., 2017). Alone and even more substantially in combination with other missions (Baker et al., 2014, 2021, Cliverd et al., 2017; Jaynes et al., 2014; Li et al., 2015, 2017a; Schiller et al., 2014, 2017; Xiang et al., 2016), the legacy CSSWE data set continues to prove its scientific merits. Owing to its design and flexibility, it not only achieved the mission's full science objectives during the main mission but continues to yield fruit after the mission's completion.…”