Aerospace applications have historically been a driver of advanced materials, from reinforced carbon–carbon thermal protection systems of space reentry vehicles to advanced metal alloy turbine blades. Although the industry now has to share the spotlight and attention of both material scientists and funding sources with potentially larger commercial market draws such as energy and health care, it still presents some unique challenges that can be met only by the application of engineered nanomaterials. This issue of MRS Bulletin reviews some of the more promising aerospace applications of nanomaterials with a focus on space rather than aeronautics, the challenges of integrating such materials into existing systems, and the challenges that remain for maturation and industry adoption.

The ability to understand and control matter at the nanoscale has enabled the development of revolutionary new materials and devices. While nanotechnology is rapidly becoming pervasive in applications such as consumer electronics, health care, and cosmetics, there are only a limited number of examples in which nanotechnology has found its way into aerospace applications. This article discusses the potential of nanotechnology to impact future aerospace missions and vehicles, as well as the technical barriers to its wider use in aerospace.

Space missions have unique requirements for payloads of electronics, sensors, instruments, and other components in terms of mass, footprint, power consumption, and resistance to various types of radiation. Nanomaterials offer the potential for future radiation-hardened or radiation-immune electronics. Gas-sensing needs in planetary exploration and crew-cabin air-quality monitoring are currently being met by bulky instruments. Routine health checkups of astronauts and testing of water in space habitats are being done on a delayed basis by bringing samples back to Earth. Instead, nanomaterials can be used to construct ultrasmall, postage-stamp-sized gas/vapor sensors with selective discrimination and also lab-on-a-chip biosensors for water-quality monitoring and crew health monitoring.

Carbon nanotubes (CNTs) have captured the imagination of the research community because of their many superior properties. In the nearly 25 years since their novelty was recognized, however, progress toward their utility as superlightweight structural materials, especially for aerospace applications, has been disappointing. Recent advancements have revived some of the anticipation for the touted systems payoffs. The purpose of this article is to examine how close CNTs have come to fulfilling expectations for lightweight aerospace structures in the two decades since the initial report stimulated intense interest in this material. This article also proposes areas of study to bridge knowledge gaps that can realize the potential for these CNT composites to be part of the lightweight structures technology suite for aerospace use.

This article reviews the application of nanomaterials for radiation shielding to protect humans from the hazards of radiation in space. The focus is on protection from space radiation, including galactic cosmic radiation (GCR), solar particle events (SPEs), and neutrons generated from the interactions of the GCR and SPEs with the intervening matter. Although the emphasis is on protecting humans, protection of electronics is also considered. There is a significant amount of work in the literature on materials for radiation shielding in terrestrial applications, such as for neutrons from nuclear reactors; however, the space environment poses additional and greater challenges because the incident particles can have high charges and extremely high energies. For materials to be considered for radiation shielding in space, they should perform more than just the radiation-shielding function; hence the emphasis is on multifunctional materials. In space, there is also the need for materials to be very lightweight and capable of surviving temperature extremes and withstanding mechanical loading. Nanomaterials could play a significant role as multifunctional radiation-shielding materials in space.

The physics underlying operation of cold (room-temperature) ionic-liquid emitter sources for use in propulsion shows that such thrusters are advantaged relative to all other “rockets” because of the direct scaling of power with emitter array density. Nanomaterials and their integration through nano- and microfabrication can propel these charged-particle sources to the forefront and open up new applications including mass-efficient in-orbit satellite propulsion and high-thrust-density deep-space exploration. Analyses of electrostatic, fluid-dynamic, and electrochemical limits all suggest that arrays of such ionic-liquid thrusters can reach thrust densities beyond most in-space propulsion concepts, with a limit on nanoporous thruster packing density of ∼1 μm due to ionic-liquid viscous flow and electrochemistry. Nanoengineered materials and manufacturing schemes are suggested for the implementation of microfabricated and nanostructured thruster arrays.

Efficient structural design and thermal management for aerospace structures demand next-generation lightweight thermally conductive and mechanically robust materials to withstand high-velocity impacts and distribute localized heat fluxes from spacecraft components. Notwithstanding the excellent mechanical, electrical, and thermal properties of individual carbon nanotubes (CNTs), bulk CNT-based composites suffer from CNT anisotropy and high interjunction resistance. We provide a brief overview of scalable methods that can tune electrical and thermal connectivity in bulk CNT composites by tuning CNT shape, intertubular bonding, and packing density. These scalable production methods are posited to open new avenues for incorporating CNTs into thermal interface materials, structural reinforcement, and auxiliary power units in the form of energy-storage devices, especially for use in aerospace applications.

Phase-change materials (PCMs) are promising candidates for novel data-storage and memory applications. They encode digital information by exploiting the optical and electronic contrast between amorphous and crystalline states. Rapid and reversible switching between the two states can be induced by voltage or laser pulses. Here, we review how density-functional theory (DFT) is advancing our understanding of PCMs. We describe key DFT insights into structural, electronic, and bonding properties of PCMs and into technologically relevant processes such as fast crystallization and relaxation of the amorphous state. We also comment on the leading role played by predictive DFT simulations in new potential applications of PCMs, including topological properties, switching between different topological states, and magnetic properties of doped PCMs. Such DFT-based approaches are also projected to be powerful in guiding advances in other materials-science fields.