MOIRE: ground demonstration of a large aperture diffractive transmissive telescope

Abstract

The desire to field space-based telescopes with apertures in excess of 10 meter diameter is forcing the development of extreme lightweighted large optomechanical structures. Sparse apertures, shell optics, and membrane optics are a few of the approaches that have been investigated and demonstrated. Membrane optics in particular have been investigated for many years. The MOIRE approach in which the membrane is used as a transmissive diffractive optical element (DOE) offers a significant relaxation in the control requirements on the membrane surface figure, supports extreme lightweighting of the primary collecting optic, and provides a path for rapid low cost production of the primary optical elements. Successful development of a powered meter-scale transmissive membrane DOE was reported in 2012. This paper presents initial imaging results from integrating meter-scale transmissive DOEs into the primary element of a 5-meter diameter telescope architecture. The brassboard telescope successfully demonstrates the ability to collect polychromatic high resolution imagery over a representative object using the transmissive DOE technology. The telescope includes multiple segments of a 5-meter diameter telescope primary with an overall length of 27 meters. The object scene used for the demonstration represents a 1.5 km square complex ground scene. Imaging is accomplished in a standard laboratory environment using a 40 nm spectral bandwidth centered on 650 nm. Theoretical imaging quality for the tested configuration is NIIRS 2.8, with the demonstration achieving NIIRS 2.3 under laboratory seeing conditions. Design characteristics, hardware implementation, laboratory environmental impacts on imagery, image quality metrics, and ongoing developments will be presented.

Transmissive diffractive membrane optic for large aperture lightweight optical telescope

“…In particular, this relay must include a complementary DOE to cancel the dispersion effects of the primary. After the pupil relay, a conventional imaging stage is used to present the scene to science instruments and sensor [11] . …”

Design and testing of infrared diffractive telescope imaging optical systems

“…Recent significant projects addressing aperture and lightweight telescope application and accessible in the US Air Force Academy and Defense Advanced Research Projects Agency [4][5][6][7][8]. .…”

Feasibility Study and Modeling of Components for an Informational Space System Based on a Large Diffractive Membrane

“…The US Agency for Defense Advanced Research Projects DARPA is working of the project of a new space telescope with a membrane diffractive optical system. The project is called MOIRE or Membrane Optical Imager for Real-Time Exploitation [1][2][3].…”

“…According to the analysis of the diffractive lens' weight in comparison to the traditional primary telescope lenses presented in [1][2][3], in average diffractive lens is about seven times ligher then a mirror of the same area. The diffractive lens for the SDMOS is estimated to weight 158.5 kg.…”