Space radiation is a significant hazard for long-duration human spaceflight. This paper reports radiation measurements from the Orion spacecraft during the Artemis I lunar mission, revealing a fourfold difference in dose rates at differing shielding locations during proton-belt passes. Interplanetary cosmic-ray dose equivalent rates were lower than previous observations, and spacecraft orientation affected radiation dose rates. These measurements validate Orion's design for future crewed exploration.

Stuart P. George, Ramona Gaza, Daniel Matthiä, Diego Laramore, Jussi Lehti, Thomas Campbell-Ricketts, Martin Kroupa, Nicholas Stoffle, Karel Marsalek, Bartos Przybyla, Mena Abdelmelek, Joachim Aeckerlein, Amir A. Bahadori, Janet Barzilla, Matthias Dieckmann, Michael Ecord, Ricky Egeland, Timo Eronen, Dan Fry, Bailey H. Jones, Christine E. Hellweg, Jordan Houri, Robert Hirsh, Mika Hirvonen, Scott Hovland, Hesham Hussein, A. Steve Johnson, Moritz Kasemann, Kerry Lee, Martin Leitgab, Catherine McLeod, Oren Milstein, Lawrence Pinsky, Phillip Quinn, Esa Riihonen, Markus Rohde, Sergiy Rozhdestvenskyy, Jouni Saari, Aaron Schram, Ulrich Straube, Daniel Turecek, Pasi Virtanen, Gideon Waterman, Scott Wheeler, Kathryn Whitman, Michael Wirtz, Madelyn Vandewalle, Cary Zeitlin, Edward Semones, Thomas Berger