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Carbon Nanotube Composites for Aerospace Applications
Published in Ann Rose Abraham, Soney C. George, A. K. Haghi, Carbon Nanotubes, 2023
Arunima Reghunadhan, Aruni Shajkumar, Jiji Abraham, K.C. Nimitha
Solar sails are nonrocket spacecraft that uses sunlight for propulsion. The dimension of solar sail is several meters wide and is made up of reflective ultrathin materials. Efficiency of solar sails is generally stated in terms of spacecraft acceleration. It is inversely proportional to the sail areal density. Conventional sails are made up of aluminized materials and consist of a reflecting layer to absorb sunlight and another layer to emit heat. CNT membranes can effectively replace these layers so that the single layer of CNT can itself reflect sunlight and emit heat. Very thin nanotube sheets weigh only few kilograms. Reflectivity of CNTs can be enhanced by doping and found special applications. Studies show that doped CNT made sail could reach Pluto in days and the nearest star in a few decades.38
Future CHEM Thin-Film Spacecraft
Published in Witold M. Sokolowski, Cold Hibernated Elastic Memory Structure, 2018
The present solar sail technology needs to be further developed, specifically in the ultra-lightweight structure area. One of the major obstacles is the solar sail material. The solar sails require an ultra-lightweight, very large structure, up to a few kilometers in size, and need to be compacted to a small size during the launch and be fully deployed in space. One of primary performance parameters for solar sails is their areal density (g/m2). This parameter is an important measure of sail performance because it determines the acceleration of the sail. Areal density is determined by the thickness and density of the sail material and the mass of the supporting structures. Dimensions range from tens of meters for small spacecraft with fairly modest mission Δν requirements to hundreds of meters for more ambitious missions to the outer solar systems. Solar sail areal density requirements range from around 20 g/m2 to perform near-term demonstration missions to around 1 g/m2 to accomplish fast missions to the heliopause and <1 g/m2 for interstellar missions.
Current and Outlook on Manufacturing and Processing Technologies
Published in Yoseph Bar-Cohen, Advances in Manufacturing and Processing of Materials and Structures, 2018
The use of flexible structures in the form of gossamer or inflatable systems offers enormous potential for many applications, including planetary exploration missions. Such structures can be used to reduce launch mass and stowed volume, where they are launched in a packed form, then inflated to shape and rigidized to create large structures. Gossamer structures may include solar sails, concentrators, and shields (Chmielewski and Jenkins, 2000). Solar sails are large flat spacecraft structures that provide propulsion using radiation pressure that is exerted by sunlight. It operates analogously to sailing boats, where the light provides a pushing force similar to sails being blown by wind (Figure 20.5). As an alternative to sunlight as the source, high-energy laser beams could be used to exert much greater force, and the concept is called beam sailing. Experimenting with this spacecraft concept has been done by the Japan Aerospace Exploration Agency with its Interplanetary Kite-craft Accelerated by the Radiation Of the Sun (IKAROS), which was launched on May 21, 2010, aboard an H-IIA rocket. This spacecraft has been the first to successfully demonstrate solar sail technology in interplanetary space, and on December 8, 2010, it passed at a distance of about 80,800 km (50,200 mi) from Venus.
Output finite-time stabilisation of a class of linear and bilinear control systems
Published in International Journal of Control, 2023
In this example, we present the control problem of solar-sail spacecraft. Solar sails are large, lightweight reflectors in space that are propelled by sunlight. Euler's rotational equations of motion of a rigid sailcraft with one axis of symmetry were introduced in Wie (2008, p. 753). Here, we consider the controlled spacecraft with one axis of symmetry studied in Haddad and L'Afflitto (2015). Our main goal here is to provide a control allowing us to achieve finite time stability in a better settling time. where are the body-axis components of the angular velocity of the sailcraft with respect to a given inertial reference frame, expressed in a central body reference frame, , where , and are the principal moments of inertia of the spacecraft with , and . The scalar-valued functions and are the spacecraft control moments.