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Both humans and onboard radiosensitive systems (electronics, materials, payloads and experiments) are exposed to the deleterious effects of the harsh space radiations found in the space environment. The purpose of this paper is to present the space radiation environment extended to deep space based on environment models for the moon, Mars, Jupiter, and Saturn and compare these radiation environments with the earth's radiation environment, which is used as a comparative baseline. The space radiation environment consists of high-energy protons and electrons that are magnetically “trapped” in planetary bodies that have an intrinsic magnetic field; this is the case for earth, Jupiter, and Saturn (the moon and Mars do not have a magnetic field). For the earth this region is called the “Van Allen belts,” and models of both the trapped protons (AP-8 model) and electrons (AE-8 model) have been developed.

Judicious shielding strategies incorporated in the initial spacecraft design phase for the purpose of minimizing deleterious effects to onboard systems in intense radiation environments will play a major role in ensuring overall mission success. In this paper, we present parametric shielding analyses for the three Jupiter Icy Moons, Callisto, Ganymede, and Europa, as a function of time in orbit at each moon, orbital inclination, and various thicknesses, for low- and high-Z shielding materials. Trapped electron and proton spectra using the GIRE (Galileo Interim Radiation Electron) environment model were generated and used as source terms to both deterministic and Monte Carlo high energy particle transport codes to compute absorbed dose as a function of thickness for aluminum, polyethylene, and tantalum. Extensive analyses are also presented for graded-Z materials.

Space radiation measurements were made on the International Space Station (ISS) with the Bulgarian Liulin-E094 Mobile Dosimetry Units (MDU) during 2001. The Liulin-E094 was part of the Dosimetric Mapping experiment lead by Dr. G. Reitz, DLR. Four MDUs were placed at fixed locations: one unit in the ISS “Unity” Node-1 and three units were located in the US Laboratory module. Space radiation flight measurements were obtained during the time period May 11 – July 26, 2001. In this paper we discuss the development of an MDU shielding model using combinatorial geometry and 3-D visualization and the orientation and placement at the four locations within the ISS. Four shielding distributions were generated for the combined ISS and MDU shielding models. The AP8MAX trapped proton model was used to compute the daily absorbed dose for the four MDUs and are compared with the flight measurements.