A scientist says it might be possible to create low-cost foldable telescope mirrors that are more than twice as large as those aboard the James Webb Space Telescope (JWST), including the iconic golden honeycomb mirror giant is the largest ever sent into space.
JWSTnetwork of 18 golden segments make up a primary mirror 21 feet 4 inches (6.5 meters) in diameter. Now, a scientist has come up with a new method to produce extremely large telescope mirrors that he says will be thinner, lighter and more affordable than most optics currently in orbit.
This new method “could help solve the weight and packaging problems of telescope mirrors, allowing much larger and therefore more sensitive telescopes to be placed in orbit,” said Sebastian Rabien, a scientist at the Max Planck Institute of alien physics in Germany and the sole author of a new study detailing the technology, said in a statement (opens in a new tab).
Related: Next-generation giant space telescopes could be built off Earth
Using his new method, Rabien constructed a mirror 30 centimeters wide. He created what is called a membrane mirror by placing an evaporated material, whose identity is not disclosed in the statement, in a vacuum chamber. Soon after, a lightweight polymeric membrane, probably as thin as household plastic wrap, began to form.
Then, to mold this membrane into a parabola – a necessity for space telescopes, as the shape allows for better focusing by directing incoming light to a single location – Rabien added a “rotating vessel filled with a small amount of liquid” inside the empty room. This allowed the polymer to expand and form the base of the mirror. Coating the mirror with a reflective surface like aluminum would make it worthy of a telescope, according to the statement.
Rabien proposes to use his new method to create massive telescope mirrors, which are usually complicated and expensive to set up. (For example, it took the JWST team eight years to build the telescope’s mirrors.) The method has the potential to create mirrors whose scale exceeds the size of those current onboard space telescopes, the release noted.
“Although this work only demonstrated the feasibility of the methods, it lays the foundation for larger and less expensive compact mirror systems,” Rabien said in the same statement. “It could make light mirrors of 15 or 20 meters [49 to 66 feet] in diameter a reality, enabling space telescopes that are orders of magnitude more sensitive than those currently deployed or planned.”
These large mirrors could be “rolled up” to fit compactly on rockets orbit safely, says Rabien. Once in the air, Rabien envisions seamless deployment of the mirrors, thanks to another method he developed that would use heat to smooth out the creases that would form after the mirrors were deployed. Such gigantic sizes would in turn make telescopes larger and more sensitive, allowing astronomers to collect higher quality observations.
Rabien details his research in a study published this month (opens in a new tab) in the journal Applied Optics.
A similar initiative was undertaken in 2010 by the US military’s advanced research wing, the Defense Advanced Research Projects Agency (DARPA), which financed a project to explore replacing traditional telescope mirrors with a polymer membrane. The goal was to create a lightweight, collapsible space telescope capable of capturing high-resolution real-time video and images of Earth.
DARPA funding for the project — known as the Membrane Optical Imager for Real-Time Exploitation, or MOIRE — was primarily for the nation’s warfighters, but the project’s scope also extended to planetary exploration. Prime contractor for MOIRE, Ball Aerospace & Technologies Corp., said (opens in a new tab) at the time when the “revolutionary approach” would “overshadow” all telescope projects in development at the time, including JWST.
However, there was little news after the the prototype of the project has been tested (opens in a new tab) at the end of 2013, and it has apparently not been used on a space mission to date.
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