urn:nasa:pds:context:instrument:clps_to_2ab_pll.lets 1.0 1.19.0.0 Product_Context 2024-05-13 1.0 Initial version. urn:nasa:pds:context:instrument_host:spacecraft.clps_to_2ab_pll instrument_to_instrument_host CLPS Task Order 2AB Linear Energy Transfer Spectrometer (LETS) Spectrometer During lunar exploration missions outside of the Earth’s protective atmosphere, exposure to space radiation has a detrimental effect on the health of the astronauts. Lunar surface environments present a greater radiation risk to the astronaut than Low Earth Orbit (LEO). There are two sources of radiation risk for lunar surface environments. The first source of risk is the total radiation dose from Galactic Cosmic Rays, which is about twice as high on the lunar surface as in LEO. The second source of risk is from space weather events resulting from solar activity. The Linear Energy Transfer Spectrometer (LETS) is a radiation monitor that is derived from heritage hardware flown on Orion EFT-1 and slated to fly on the Orion EM-1 mission that will enable acquisition of knowledge of the lunar radiation environment and demonstrate the capabilities of a system on the lunar surface. The LETS radiation sensor is a solid-state silicon Timepix detector that is derived from heritage hardware that was flown on Orion EFT-1. This sensor measured the rate of incident radiation providing information that is critical to understanding and mitigating the hazardous environment that people will experience as they explore the surface of the Moon.