For more than 25 years, the Hubble Space Telescope has provided stunning photos of the universe unequalled in their depth, detail, and distinction. But in its early days, Hubble wasn't capable of sending back such breathtaking photos. Within weeks of launch, the images beamed back to Earth were fuzzy and out of focus. It was determined that Hubble's primary mirror had been ground to the wrong shape and was too flat by 2.2 micrometers, causing reflected light from the edge of the mirror to be focused on a different point than light coming from near the center. It was determined that the device used to create the nonspherical mirror had been incorrectly assembled, and the mirror's manufacturer had failed to notice the problem before Hubble was launched.
NASA decided on a two-step approach to address the problem. During the first repair mission to Hubble, astronauts would replace the Wide Field Planetary Camera (WFPC) with an improved version featuring advanced detectors and more accurate contamination control, along with built-in corrective optics known as WFPC 2. Second, the astronauts would replace one of Hubble's original components, the High-Speed Photometer, with the Corrective Optics Space Telescope Axial Replacement (COSTAR), which would work like a pair of eyeglasses to better focus the telescope's view of the universe. But first, NASA wanted to make sure the repairs would indeed improve Hubble's ability to capture images, and not suffer from any undiscovered flaws.
NASA put out a call for optics companies to prove they could verify the shape of a mirror hidden from view and detect any defects, however slight. Along with other companies, AOA Xinetics, now a Cambridge, MA-based subsidiary of Northrup Grumman, went to Goddard Space Flight Center with its aberrated beam analyzer (ABA), which it built to meet NASA's specific requirements. AOA needed to use its analyzer to determine both the mirror's flaw and how to compensate for the fuzzy image using a static corrector.
Prior to creating the ABA, AOA had experience in measuring the way the atmosphere bends and distorts light, a process that requires split-second measurements but not high levels of accuracy relative to the measurements NASA needed. The team decided to illuminate the mirror using flat wavefronts of light from a laser, knowing that the waves bouncing back could allow the ABA to detect the unseen mirror's shape, right down to microscopic divots and bumps. The resulting instrument not only detected the mirror's shape accurately, but did so to within three-thousandths of a wavelength of light. NASA chose the tool used to verify that both COSTAR and WFPC 2 were perfect before being sent into space.
Shortly after the work on Hubble, AOA used the ABA to create the Mass Scanning and Dimensioning System, originally used by FedEx to quickly and accurately create 3D images of packages that would need to be sorted and shipped in a given day. The scanning system creates a contour map of parcels as they travel down a conveyor belt past a laser ranging imager. Height contours are subsequently analyzed to determine the location of each parcel and its dimensions, which helps to identify packages that might require additional charges due to size or weight. Previously, someone would have to manually pull items off conveyor belts and use a tape measure to single out packages.
The imaging system, which has since been adopted by all major shipping services including the U.S. Postal Service, has been utilized by hundreds of machines running millions, if not billions, of hours for 20 years.
AOA also partnered with Kroger grocery stores to develop the Scan Tunnel to ease checkout at its stores. Customers put their products on a conveyor belt, which then travels through an upright tunnel with laser scanners on three sides, capturing product information for identification and pricing. This allows customers with larger orders to take advantage of self-checkout aisles. Scan Tunnel uses 14 scanning cameras and two types of dimensioners, an improvement over the seven cameras and one dimensioner used in FedEx's system.
Both products have roots in the initial work to save Hubble from obsolescence. Now, after more than 25 years, Hubble continues to provide breathtaking images of the galaxy, long exceeding the optimistic predictions that it would send back views of the heavens for only 15 years.