Given the increased availability of small satellite opportunities either through CubeSats or the Air Force’s University Nanosat program, and the limited availability of larger platforms, it is challenging to develop new instrumentation that not only fits within the envelope of small satellites, but also addresses the diverse science applications available in low Earth orbit (LEO). While small-platform instrumentation is limited in sensitivity, the ability to populate LEO with a fleet of instruments opens new science objectives not available with larger standalone payloads. Furthermore, coordinated observations of a variety of radiation species that either enter LEO from the Sun or heliosphere directly, or that reside within the radiation belts themselves, are necessary to fully reach closure on complex processes that govern particle acceleration and transport.

An instrument prototype was built and calibrated that can measure energetic gamma rays, neutrons, and energetic particles with good efficiency that can be readily expanded to suit small satellite platforms. A key asset of the instrument design is the ability to measure a broad range of radiation, which can address several critical science goals of solar and heliospheric physics, as well as the radiation environment in LEO.

As volume, mass, and power are severely constrained on small satellites, and development funds are limited, taking full advantage of these platforms will require flexible, compact, lightweight, and low-power detectors to be developed and available for rapid integration into payloads. The instrumentation proposed will be based on scintillators with advanced compact readout and electronics. Scintillator detector materials have a long history in the measurement of gamma rays and neutrons, and provide a variety of advantages for space instrumentation including low cost, high stopping power, straightforward implementation that is readily scalable, room-temperature operation, and good energy and timing resolution.

The instrument concept is based on a compact, low-mass, and low-power double-scatter neutron/ray/particle detector developed for the Solar Probe Plus mission: the Solar PRobe Ion, Neutron, and Gamma-ray Spectrometer (SPRINGS). SPRINGS is a unique instrument concept that uses a novel configuration of simple, organic scintillator inner heliosphere, solar neutrons (120 MeV) and gamma rays (0.120 MeV).

SPRINGS consists of individual plastic and organic crystal scintillator blocks (3 cm thick) that record neutron and ray scatters, interleaved with thin plastic sheets (5 mm thick) to detect charged particles. Incorporating similar blocks made of inorganic scintillator would further improve the gamma ray response, and perhaps extend the energy range for neutron and particle detection.

This work was done by Georgia De Nolfo of Goddard Space Flight Center. For further information, contact the Goddard Technology Transfer Office at (301) 286-5810. GSC-16969-1