ACCESS: advanced cosmic-ray composition experiment for the space station

The Advanced Cosmic-ray Composition Experiment for Space Station (ACCESS) is a space science payload that will be deployed on the International Space Station (ISS). The ACCESS mission will help address the NASA Structure and Evolution of the Universe (SEU) theme\´s quest "to explore the cycles of matter and energy in the evolving universe." ACCESS utilizes two insitu instruments to study cosmic ray shower events induced in the instruments from the vantage point of the ISS. ACCESS records these events in an energy spectra range between 10¹² and 10¹⁵ eV. This paper describes the end-to-end mission concept design, including flight hardware and mission operations. The flight hardware design addresses the ACCESS science requirements, as well as the interface requirements of the ISS and the launch and landing requirements of the shuttle. The ACCESS flight hardware consists of two science instruments and the Payload Support and Interface Module (PSIM). The PSIM serves as a carrier in the space shuttle cargo bay during launch and landing for transportation to and from the ISS and, thereafter, provides system support to the instruments when the ACCESS payload is mated onto the ISS starboard truss. The on-orbit mission life is 4 years and the mission takes advantage of the inherent capability of the ISS to accommodate large and massive payloads. The ACCESS mission requirements are compatible with the ISS environments and the resources provided by the ISS are suitable for meeting mission orbit objectives. The mission concept design demonstrates the feasibility of the ACCESS mission on the ISS