Design and scientific return of a miniaturized particle telescope onboard the Colorado Student Space Weather Experiment (CSSWE) CubeSat

Abstract

The Relativistic Electron and Proton Telescope Integrated Little Experiment (REPTile) is a loaded-disc collimated solid-state particle telescope designed, built, tested, and operated by a team of students at the University of Colorado. It was launched onboard the Colorado Student Space Weather Experiment (CSSWE), a 3U CubeSat, from Vandenberg Air Force Base on September 13th, 2012, as part of NASA's Educational Launch of Nanosatellites (ELaNa) program.REPTile takes measurements of energetic particles in the near-Earth environment. These measurements, by themselves and in conjunction with larger missions, are critical to understand, model, and predict hazardous space weather effects. However, miniaturizing a power-and mass-hungry particle telescope to return clean measurements from a CubeSat platform is extremely challenging. To overcome these challenges, REPTile underwent a rigorous design and testing phase. This paper highlights some of the design and testing which validates the data as a valuable contribution to the study of space weather. CSSWE uses a keep-it-simple design approach to minimize risks associated with low budget and student built missions. A coherent testing plan confirmed that the spacecraft would remain healthy and take reliable measurements in orbit. This paper also highlights the system-level design and testing that verified spacecraft performance pre and post launch.Despite the risks inherent CubeSat missions, REPTile to date has returned over 300 days of valuable science data, more than tripling its nominal mission lifetime of 90 days. Initial in-flight instrument results are presented, including engineering hurdles encountered in receiving and processing the data. Also, the preliminary scientific contributions of the mission are covered in this paper to demonstrate the capabilities of a low-budget CubeSat mission. As an affordable, robust, and simple instrument and mission design, CSSWE demonstrates that small satellites are a reliable platform to deliver quality science.

Detailed characteristics of radiation belt electrons revealed by CSSWE/REPTile measurements: Geomagnetic activity response and precipitation observation

“…CSSWE is a LEO CubeSat designed, built, and operated by students at University of Colorado Boulder with close mentorship from professionals and was deployed into orbit on 13 September 2012 with an inclination of 65° and 480 km × 790 km altitude [ Li et al , , ]. The sole science instrument onboard CSSWE is the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), which measures the electron and proton flux with a time resolution of 6 s. REPTile uses the energy deposit (threshold) of each particle to determine the species and uses the penetration depth to determine the energy of the particle [ Schiller and Mahendrakumar , ; Blum and Schiller , ; Li et al , ; Schiller et al , ]. REPTile has three energy channels for both electrons and protons: 0.58–1.63 MeV, 1.63–3.8 MeV, and >3.8 MeV for electrons (referred to as the first, second, and third channels hereinafter) and 9–18 MeV, 18–30 MeV, and 30–40 MeV for protons.…”

Investigating energetic electron precipitation through combining ground‐based and balloon observations

“…Based on the depth of penetration into the stack, and the energy deposited in each detector, the measurements are binned into three electron energy channels (E1 = 0.58–1.63 MeV, E2 = 1.63–3.8 MeV, and E3 ≥ 3.8 MeV). Due to the strong scattering of energetic electrons in the detector materials, some fraction of the electrons below 1.63 MeV will impact the second detector and trigger the second energy channel E2 [e.g., Schiller et al , , Figure 3]. This is typically corrected for in the data processing by assuming a power law spectrum (see Li et al [] for details).…”

Miniature X-Ray Solar Spectrometer: A Science-Oriented, University 3U CubeSat

“…CubeSat technologies and capabilities are now sufficiently mature to enable peer-review-journal quality science missions. This was clearly proven with the CSSWE CubeSat, which has 17 such articles to date [1,2,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] .…”