Radiation exposure in low Earth orbit measured with the RAMIS instrument on the DLR Eu:CROPIS satellite

The radiation environment in space and the related radiation exposure is seen as one of the main health detriments for human missions in and beyond low Earth orbit (LEO). In addition to national space agencies sending astronauts to space, the near future is likely to bring numerous commercial endeavours that will facilitate the access to space, and specifically to LEO, for a growing number of people. The components of the cosmic radiation forming the environment in LEO are the galactic cosmic radiation (GCR), inner and outer radiation belt particles and sporadic solar energetic particle events. The steady flux of energetic particles in the galactic cosmic radiation produces a chronic low-dose-rate exposure, which is heavily influenced by several factors including variations during the solar cycle, the Earth’s magnetic field and spacecraft shielding. Investigations of the GCR variations over the course of a solar cycle provide valuable data for exploration mission planning and for the determination of the radiation load received due to the GCR environment. The RAMIS (Radiation Measurement in Space) instrument onboard the DLR Eu:CROPIS satellite, named after its primary payload: Euglena and Combined Regenerative Organic-Food Production in Space, has been measuring the radiation environment in a sun-synchronous polar orbit at 500 km to 600 km altitude since December 2018 and has been providing data on the exposure from GCR, inner and outer radiation belt particles and during numerous solar energetic particle events. Measurements at high latitudes and low geomagnetic shielding provide information on the exposure outside the magnetosphere in near-Earth interplanetary space.