Enhancing astronomers' ability to peer more deeply into the cosmos may hinge on developing larger space-based telescopes. A new concept in space telescope design makes use of a modular structure and an assembly robot to enable construction of a large telescope in space, performing tasks in which astronaut fatigue would be a problem.

The robotically assembled modular space telescope design is described by Nicolas Lee and his colleagues at the California Institute of Technology and the Jet Propulsion Laboratory in an article published in the Journal of Astronomical Telescopes, Instruments and Systems.

Ground-based telescopes are limited by atmospheric effects and by their fixed location on the Earth. Space-based telescopes do not have those disadvantages but have other limits, such as overall launch vehicle volume and mass capacity. Design of a modular space telescope that overcomes restrictions on volume and mass could allow components to be launched incrementally, enabling the deployment of extremely large space telescopes.

CAD rendering of an assembly robot deploying a truss module. Folded truss modules are stored in a cargo housing unit shown docked to the central hub. Image credit: SPIE/JATIS.The main features of the authors' proposed architecture include a mirror built with a modular structure, a robot to put the telescope together and provide ongoing servicing and advanced metrology technologies to support the assembly and operation of the telescope. An optional feature is the potential ability to fly the unassembled components of the telescope in formation. The system architecture is scalable to a variety of telescope sizes and is not limited to particular optical designs.

The capability to assemble a modular space telescope has other potential applications, says Harley Thronson, senior scientist for Advanced Astrophysics Concepts at NASA's Goddard Space Flight Center. "For example, astronomers using major ground-based telescopes are accustomed to many decades of operation, and the Hubble Space Telescope has demonstrated that this is possible in space if astronauts are available. A robotic system of assembly, upgrade, repair and resupply offers the possibility of very long useful lifetimes of space telescopes of all kinds."