The potential of LEO CubeSats for science, and radiation environment specification.

Flights of small satellites in the lower-end of the Low-Earth Orbit (LEO) environment, at altitudes 400-800km, provide an opportunity to measure both precipitating and locally trapped particles. This can be accomplished with a simple one-directional narrow field of view detector, spinning fast (a few seconds) along and across the local magnetic field. The trapped particle fluxes at lower-end of LEO are close enough to those at the higher-end, 800-4000km, such that extrapolation using simple functional forms of flux variation with pitch-angle obtained from the lower-end can result in good specification of fluxes at the higher-end. Because the lower-end LEO environment (especially near 450km or below) does not suffer from radiation effects, highly capable CubeSats can now be launched at a low cost and in large numbers to achieve significant scientific returns even during their short lifetime (1-2 years to passive re-entry). Therefore, a new way of comprehensively exploring the complex space environment from lower-end LEO is now emerging. These can serve both as scientific trailblazers and space environment monitors. Cross-calibration and absolute calibration are both important, and current missions (e.g., POES) can be used to facilitate that. We discuss new science that has been obtained from such missions and provide ideas for future exploration with new concepts from that altitude.