Aerospace and Astronomy:
In the aerospace and astronomy industries, the Webb program gave 4D Technology its first commercial contract to develop the PhaseCam Interferometer system, which measures the quality of the Webb telescope's mirror segments in a cryogenic vacuum environment. This is a new way of using interferometers in the aerospace sector.
An interferometer is a device that separates a beam of light into two beams, usually by means of reflection, and then brings the beams together to produce interference, which is used to measure wavelength, index of refraction, and also distances.
Interferometry involves the collection of electromagnetic radiation using two or more collectors separated by some distance to produce a sharper image than each telescope could achieve separately.
The PhaseCam interferometer verified that the surfaces of the Webb telescope's mirror segments were as close to perfect as possible, and that they will remain that way in the cold vacuum of space. To test the Webb mirror segments, they were placed in a "cryovac" environment, where air is removed by a vacuum pump and temperatures are dropped to the extreme cold of deep space that the space craft will experience. A new dynamic interferometric technique with very short exposures that are not smeared by vibration was necessary to perform these measurements to the accuracy required, particularly in the high-vibration environment caused by the vacuum chamber's pumps.
The interferometer resulting from this NASA partnership can be used to evaluate future
|Contact: Lynn Chandler|
NASA/Goddard Space Flight Center