Session
Science/Mission Payloads Research & Academia
Location
Salt Palace Convention Center, Salt Lake City, UT
Abstract
Neutron interactions in Low Earth Orbit (LEO) remain a poorly characterized component of the space radiation environment, despite their potential to significantly impact spacecraft electronics, materials, and crew health. Unlike primary charged particles, most neutrons in LEO are secondary products generated when high-energy protons and heavy ions from galactic cosmic rays or solar energetic particle events interact with atoms and molecules in Earth’s atmosphere. The production rate of these secondary neutrons is strongly dependent on atmospheric density, which varies with altitude, geomagnetic position, and solar activity, leading to spatial and temporal variability that is not well captured by current radiation models. The Neutron-2 CubeSat mission is designed to address this gap by measuring neutron and gamma-ray fluxes as a function of time, geomagnetic position, including altitude, latitude, longitude, and solar activity. By directly characterizing how neutron flux varies with orbital parameters, Neutron-2 will improve understanding of secondary neutron generation in LEO and contribute to more accurate radiation risk assessments for spacecraft systems and human missions. To enable these measurements, Neutron-2 employs a dual-spacecraft architecture consisting of two identical CubeSats deployed into distinct polar orbits at different altitudes. Operating concurrently, the two spacecraft will collect synchronized radiation measurements, enabling direct cross-comparison of neutron fluxes as a function of altitude while minimizing temporal and solar variability effects. The resulting dataset will support the generation of three-dimensional maps of neutron radiation in Earth orbit, providing new insights into the structure of the LEO neutron environment. Beyond its immediate scientific objectives, Neutron-2 serves as a technology and mission-operations pathfinder for future distributed radiation-monitoring missions. The dual-spacecraft configuration enables experiments in relative attitude control, formation awareness, and coordinated operations, laying the groundwork for more complex multi-spacecraft architectures. These capabilities directly inform a future mission concept, envisioned as a small-satellite swarm designed to measure radiation environments in cislunar space, where exposure levels and particle populations differ substantially from LEO and are increasingly relevant to sustained human exploration of the Moon and beyond. The neutron detectors for Neutron-2 are developed by Radiation Monitoring Devices, Inc. (RMD) in collaboration with Arizona State University (ASU), incorporating lessons learned from the Neutron-1 CubeSat mission launched in 2020. Neutron-2 introduces a next-generation payload and a new spacecraft bus designed to provide increased radiation tolerance and an extended orbital lifetime. The mission is led by students at the University of Hawaiʻi at Manoa (UHM), with mentorship from faculty and industry partners, and is supported by the Air Force Research Lab–sponsored University Nanosatellite Program (UNP). Neutron-2 advances scientific understanding of space radiation, matures distributed CubeSat mission operations, and trains the next generation of aerospace engineers for future multi-spacecraft missions.
Document Type
Event
Neutron-2: A Dual CubeSat Mission for Three-Dimensional Mapping of Neutron Radiation in Low Earth Orbit
Salt Palace Convention Center, Salt Lake City, UT
Neutron interactions in Low Earth Orbit (LEO) remain a poorly characterized component of the space radiation environment, despite their potential to significantly impact spacecraft electronics, materials, and crew health. Unlike primary charged particles, most neutrons in LEO are secondary products generated when high-energy protons and heavy ions from galactic cosmic rays or solar energetic particle events interact with atoms and molecules in Earth’s atmosphere. The production rate of these secondary neutrons is strongly dependent on atmospheric density, which varies with altitude, geomagnetic position, and solar activity, leading to spatial and temporal variability that is not well captured by current radiation models. The Neutron-2 CubeSat mission is designed to address this gap by measuring neutron and gamma-ray fluxes as a function of time, geomagnetic position, including altitude, latitude, longitude, and solar activity. By directly characterizing how neutron flux varies with orbital parameters, Neutron-2 will improve understanding of secondary neutron generation in LEO and contribute to more accurate radiation risk assessments for spacecraft systems and human missions. To enable these measurements, Neutron-2 employs a dual-spacecraft architecture consisting of two identical CubeSats deployed into distinct polar orbits at different altitudes. Operating concurrently, the two spacecraft will collect synchronized radiation measurements, enabling direct cross-comparison of neutron fluxes as a function of altitude while minimizing temporal and solar variability effects. The resulting dataset will support the generation of three-dimensional maps of neutron radiation in Earth orbit, providing new insights into the structure of the LEO neutron environment. Beyond its immediate scientific objectives, Neutron-2 serves as a technology and mission-operations pathfinder for future distributed radiation-monitoring missions. The dual-spacecraft configuration enables experiments in relative attitude control, formation awareness, and coordinated operations, laying the groundwork for more complex multi-spacecraft architectures. These capabilities directly inform a future mission concept, envisioned as a small-satellite swarm designed to measure radiation environments in cislunar space, where exposure levels and particle populations differ substantially from LEO and are increasingly relevant to sustained human exploration of the Moon and beyond. The neutron detectors for Neutron-2 are developed by Radiation Monitoring Devices, Inc. (RMD) in collaboration with Arizona State University (ASU), incorporating lessons learned from the Neutron-1 CubeSat mission launched in 2020. Neutron-2 introduces a next-generation payload and a new spacecraft bus designed to provide increased radiation tolerance and an extended orbital lifetime. The mission is led by students at the University of Hawaiʻi at Manoa (UHM), with mentorship from faculty and industry partners, and is supported by the Air Force Research Lab–sponsored University Nanosatellite Program (UNP). Neutron-2 advances scientific understanding of space radiation, matures distributed CubeSat mission operations, and trains the next generation of aerospace engineers for future multi-spacecraft missions.
