IMpulsive Phase Rapid Energetic Solar Spectrometer
IMPRESS (IMpulsive Phase Rapid Energetic Solar Spectrometer) is a solar science mission that will fly a hard X-ray (>10 keV) spectrometer on a 3U CubeSat to investigate particle acceleration in solar flares. IMPRESS will perform soft and hard X-ray (SXR and HXR, respectively) spectroscopy of solar flares in the rising phase of a solar cycle. IMPRESS is optimized to observe high-cadence HXR and SXR spectra from a wide range of solar flares (targeting C1 to X1 class flares) without saturating the detector and without the need for disruptive movable attenuators. These measurements will be used to (1) investigate sub-second variations in HXR flux that strongly constrain flare acceleration timescales; (2) perform a mission of opportunity by co-observing HXRs from solar flares along with the Spectrometer/Telescope for Imaging X-rays (STIX) onboard Solar Orbiter, systematically studying directivity; and serve as a HXR monitor of flares associated with solar eruptive events that will drive space weather in the next solar cycle.
SSEL is responsible for development of the IMPRESS instrument payload, while the University of Minnesota SmallSat Program is responsible for construction of the 3U CubeSat platform.
The IMPRESS detectors are four CeBr scintillator crystals read out by silicon photomultipliers and one Amptek X123 silicon drift diode. To capture fast time variations, these detectors will produce 4-12 keV SXR spectra at a 1 Hz cadence and 8-100 keV HXR spectra at a 32 Hz cadence.
The IMPRESS instrument has finished the engineering phase and work has begun on procuring and producing flight hardware.
The projected launch date of the spacecraft is late 2024.
 Courtesy of the University of Minnesota SmallSat Program, https://smallsat.umn.edu/impress