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RHEME

The Radiation Hardened Electronic Memory Experiment (RHEME) was UNM’s first flight on the International Space Station. In conjunction with NASA Johnson and AFRL, the system is designed to measure memory upsets due to exposure to protons and galactic cosmic rays in space. A secondary experiment using a sensor from RMD Corporation will permit total ionizing dose to be measured with a distinction between electron dose and proton dose. The memory units used in the primary experiment were designed by the Silicon Space Technologies Corporation. The memory space includes four 16Mbit SRAMs, available from Texas Instruments as qualified parts, and one 72Mbit SRAM stack composed of four 18Mbit SRAMs. They will be used for testing SEU mitigation schemes at the architecture and system levels. The STP-H5 RHEME experiment was delivered to NASA Johnson in July 2015 and launched during the month of August 2016. RHEME-II launched on the STP-Sat-5 mission in December 2018. RHEME-III is scheduled to be launched in June 2021.

There are two follow on programs to RHEME. The first is ARHEME which is an upgraded version of RHEME with newly developed memories. This program is funded by the Air Force Research Laboratory. The second is LRHEME which is a proposed lunar version of the system that is designed to land and operate on the moon’s surface.

RHEME II

photo of rheme, dave and alonzo

photo of rheme
Above: RHEME on the international space station

photo of rheme
Above: RHEME on the international space station