Overview of the Natural Space Environment and ESA, JAXA, and NASA Materials Flight Experiments

Abstract

velocity. Technology improvements allow higher resolution measurements; computing efficiency provides higher precision modeling; and our understanding of the space environment constituency improves. This overview will provide a general description of the space environment and point to some key features that spacecraft designers need to consider to reduce risk and improve engineering performance. The best metric that spacecraft designers can use to assess the engineering performance of the spacecraft is to understand environmental effects on the spacecraft materials, particularly through flight experiments exposed to the space environment in which the spacecraft will operate. This understanding begins with characterizing the natural space environment, then progresses to ground-based materials testing, and culminates with flight experiments. The following are process steps that spacecraft engineers should ideally follow to assess the performance and guide selection of candidate materials for spacecraft application:Define mission-specific space environment.Consider induced environment factors that could influence material engineering performance.Determine failure criteria for candidate materials.Perform literature search for previous space environment testing or flight experiments on candidate materials.Determine acceptable acceleration factors for ground testing.Perform ground tests, including appropriate/available synergistic effects.Expose material on a flight experiment in the space environment. Space EnvironmentThe natural space environment is a dynamic synergy of its constituents, comprised of many components that vary in intensity and interact with each other through both constructive and destructive mechanisms. The first step in understanding the engineering performance of a material in the space environment is to understand the operational space environment and the interactions with the spacecraft materials. Today, the space environment engineer has a very good understanding of the environmental constituents and has models to predict the flux, fluence, and spatial distributions of each component. The part of the predictive tool that is missing is a thorough understanding of the synergy of how these individual components of the environment interact and produce effect in materials. Often these synergistic effects are not accurately simulated in ground test facilities.

Atomic oxygen degradation mechanisms of epoxy composites for space applications

“…When deployed in low Earth Orbit (LEO), satellites are particularly prone to AO exposure (with kinetic energy of 5eV, nominal AO flux of around 10 14 -10 15 atoms/ cm 2 s), which plays a major role in the degradation of polymer based composite materials [3]. Several in-orbit tests have been performed by the European Space Agency (ESA) [4], Japan Aerospace Exploration Agency (JAXA), and the National Aeronautics and Space Administration (NASA) [5e8], to understand the AO resistance of various materials, and these have been reviewed [9]. Extensive research has been undertaken to investigate the AO resistance of composite materials using ground-based facilities, but few publications focus on the AO behaviour of space-qualified composites that are already used in orbit.…”

Advanced Aromatic Polymers with Excellent Antiatomic Oxygen Performance Derived from Molecular Precursor Strategy and Copolymerization of Polyhedral Oligomeric Silsesquioxane

“…In the LEO circumstance, the space effect on materials is very severe and complex because of the synergistic interaction of orbital environments such as high-energy radiation particles, atomic oxygen, micrometeoroids, orbital debris, and ultraviolet irradiation interacting synergistically, along with thermal exposure . It was reported that AO fluence in LEO was from 1 × 10 12 to ∼1 × 10 15 atom cm –2 s –1 , and exposure of 2.0 × 10 20 atom cm –2 was roughly equivalent to 6 months exposure to AO in an LEO circumstance .…”

Nondestructive Testing of Polymers and Polymer–Matrix Composites

“…In particular, piezoceramic transducers for sonic and ultrasonic NDT may generate spurious signals or noise from pyroelectric effects, if exposed to temperature changes in time (388). Spacecraft are exposed to an even more complex environment (389), and designing and developing durable SHM systems for reliable, long-term monitoring of these is a considerable challenge.…”