Ball Aerospace Demonstrates Ultra-Lightweight Telescope

Instead of using traditional glass mirrors or lenses, MOIRE seeks to diffract light with Fresnel lenses made from a lightweight membrane roughly the thickness of household plastic wrap. MOIRE would house the membranes in thin metal “petals” that would launch in a tightly packed configuration. Upon reaching its destination orbit, the satellite would then unfold the petals to create the full-size multi-lens optics. Image Credit: DARPA

Instead of using traditional glass mirrors or lenses, MOIRE seeks to diffract light with Fresnel lenses made from a lightweight membrane roughly the thickness of household plastic wrap. MOIRE would house the membranes in thin metal “petals” that would launch in a tightly packed configuration. Upon reaching its destination orbit, the satellite would then unfold the petals to create the full-size multi-lens optics. Image Credit: DARPA

Boulder, Colorado. December 6, 2013. Ball Aerospace & Technologies Corp. has demonstrated unprecedented telescope technologies using ultra-lightweight polymer membrane optics.

Ball is incrementally demonstrating technology needed to deploy a large, 20-meter-diameter, lightweight space-based telescope in geosynchronous orbit as part of the Membrane Optic Imager Real-time Exploitation (MOIRE) program, led by the Defense Advanced Research Projects Agency (DARPA).

With a proposed diameter of 20 meters, MOIRE’s membrane optic “lens” would be the largest telescope optics ever made and dwarf the traditional glass mirrors used in the world’s most famous telescopes. Image Credit: DARPA

With a proposed diameter of 20 meters, MOIRE’s membrane optic “lens” would be the largest telescope optics ever made and dwarf the traditional glass mirrors used in the world’s most famous telescopes. Image Credit: DARPA

Most recently, Ball completed construction and testing of one-eighth of a 5-meter-diameter annular segmented telescope to verify functionality of the MOIRE design.

“The ground demonstration substantiates that this innovative technology could work on next generation space telescopes to greatly reduce their costs and enable larger telescopes,” said Ball Aerospace President Rob Strain. “This technology could apply to a wide-range of applications – to provide various forms of information to a multitude of users.”

The lightweight optics developed under the MOIRE program reduces the mass of large aperture telescopes by nearly an order of magnitude compared to those with conventional optics. Since costs scale roughly with spacecraft mass, one key to affordability is minimizing the mass of future space optics. This technology could lend itself to easily stowed configurations for launch within a payload shroud that could be deployed on orbit.

The telescope concept that Ball developed employs thin (less than 1/1000th of an inch) transparent membranes etched with a diffraction pattern as the primary optical element used to focus light.

“This is the first design to use transparent membranes on a large scale,” said Aaron Seltzer, director of Advanced Development for Ball Aerospace’s National Defense business unit. “The result is a telescope with exceptionally low mass per unit of collecting area.”

To produce MOIRE’s optical-quality polymer membranes and the precision etching needed to generate the diffraction pattern, Ball worked with NeXolve and the Lawrence Livermore National Laboratory. The Ball demonstration telescope uses six primary diffractive optical elements. Additional technologies demonstrated by Ball for the MOIRE telescope include the use of secondary diffractive optical elements to correct chromatic dispersion (e.g. the rainbow effect visible on the reverse side of a DVD); stability of the membranes; and the use of laser metrology and active optics to align the primary and secondary optics.

Following the successful ground-based proof of concept for MOIRE, the Ball team intends to pursue additional funding to move the technology forward.

Source: Ball Aerospace & Technologies Corp.