The Ball Fiber Optical Comb Demo is a lab-based system which is used to develop space applications for optical frequency combs. These developments utilize the broadband optical coherence of the frequency comb to expand the capabilities of ground test and orbital systems used for optical wave-front measurement, control of adaptive optics, precision ranging, and reference frequency stabilization. The work expands upon a NIST-developed all-fiber frequency comb that exhibits high stability in a compact, enclosed package.
Previously demonstrated applications for frequency combs include: Spectroscopy, distance and velocity measurement, frequency conversion, and timing transfer. Results from the Ball system show the characterization and performance of a frequency comb system with a technological path-to-space. Demonstrations in high precision metrology and long distance ranging are also presented for application in adaptive and multi-body optical systems.
The Primary Mirror (PM) of NASA’s James Webb Space Telescope (JWST) consists of 18 segment assemblies that are
aligned on-orbit using hexapod actuators to function as a single monolithic optic. The individual segment assemblies are
polished into one of three different prescriptions. Each segment of a given prescription may be placed in one of six
different locations for that prescription, resulting in tens of millions of possible placement combinations of the 18
segments on the backplane of the telescope. A method is proposed to optimize the placement based on minimizing the
known alignment offsets of as-built mirrors in combination with the predicted shifts of each attachment point on the
telescope backplane due to material creep, cool down shifts, launch shifts, and gravity release. The optimization routine
can be configured to allow for minimization of errors in any of the six rigid-body degrees of freedom and can further
reduce selection options based on defined hardware constraints. Such a routine can be utilized to minimize initial
misalignments of the PM on-orbit, reducing the need to exercise mirror actuators to achieve an aligned state. The end
result is reduced commissioning time and increased probability of success of the mission.