EP30LTE-LO: Used in Composite Conical Reflector on the International Space Station

Overview

The document presents a case study on Master Bond's EP30LTE-LO, a specialty epoxy system used in the construction of a composite conical reflector for the International Space Station (ISS). This epoxy is notable for its low coefficient of thermal expansion (CTE) and its ability to function in cryogenic conditions, with a temperature range from 4K to +250°F. It also meets NASA's low outgassing requirements, making it suitable for high-vacuum applications in space.

The conical reflector is part of the Alpha Magnetic Spectrometer (AMS), a particle physics experiment module mounted on the ISS. The AMS is dedicated to exploring fundamental physics, including the search for antimatter and the study of cosmic rays. To achieve precise measurements of charged particles, the AMS employs a Ring Imaging Cerenkov Detector (RICH), which relies on the Cerenkov effect to measure particle velocities. However, only about 30% of the Cerenkov photons produced are directed toward the detector. To enhance photon collection, a conical reflector was designed and constructed.

The reflector was made from three 120-degree cyanate ester composite segments, which were adhered together using EP30LTE-LO. The construction process involved a replica technique, starting with a mandrel that defined the shape and dimensions of the reflector. The carbon fiber-reinforced composite (CFRC) was applied to the mandrel, followed by oven curing under vacuum to ensure proper positioning and reflectivity. A thin layer of resin was applied between the CFRC and the mandrel, followed by a second curing process. The flanges and ribs were also adhered using EP30LTE-LO, and the segments were assembled using the mandrel as a jig.

To achieve the required reflectivity of over 85% at a wavelength of 420 nm, a reflective coating was applied, consisting of a 100 nm layer of aluminum and a 300 nm layer of SiO2. The final reflector demonstrated a surface roughness of less than 5.3 nm and met the reflectivity requirements.

The AMS-02 was launched in May 2011 and has since collected data from over 246 billion cosmic ray events, contributing significantly to our understanding of the universe. The document highlights the critical role of advanced materials like EP30LTE-LO in space exploration and scientific research.