These instruments could form multispectral images of transient scenes from ultraviolet through infrared.

This innovation enhances the measurement of the alignment of cryogenic structures at their operating temperature. Every spacecraft and associated science instrument has a system of fiducials and datum surfaces that define a coordinate system for precision alignment of sensitive components (e.g., gyros and optics). This metrology relies on COTS alignment instruments like theodolites for precision assembly. Many spacecraft and instruments operate at temperatures lower than ambient conditions on Earth. These cryogenic instruments are typically assembled at room temperature with ambient metrology and tested in a vacuum chamber at the operating temperature. The chamber often provides poor line-of-sight to components, so little metrology data is obtained. If science data indicate a problem with alignment at temperature for a complex optical system, it can be difficult to pinpoint the specific errant component(s) without this metrology. Coordinate systems are referenced to a reflective optical alignment cube with known orientation with respect to a feature of importance on the structure. The cube's orientation in rotations is measured using autocollimating theodolites. For a calibrated cube, at least two orthogonal sides must be visible to establish its orientation in the laboratory — using two theodolites. For cubes on cryogenic assemblies, this requires that the chamber support two windows providing orthogonal lines-of- sight to the cube. It is expensive to retrofit chambers with additional windows. This innovation is a new cube that only requires one line-of-sight to measure its orientation in all three rotational degrees of freedom with one theodolite. The new cube uses a diffractive, grating-like surface on one face. Measurement of both the specular and diffracted orders from this surface provides complete metrology of all three rotational degrees of freedom.

Precise lithographic fabrication would solve a large part of the alignment problem.

Diffractive optical elements with continuous phase profiles can be designed rapidly.