A key component of the James Webb Space Telescope (JWST) has come through its latest tests at NASA's Goddard Space Flight Center with flying colors. According to Lockheed Martin, the Near Infrared Camera (NIRCam) instrument exceeded requirements during Integrated Science Instrument Module (ISIM) testing and will now be integrated into the telescope's instrument cluster for combined testing.
Built by Lockheed for NASA and the University of Arizona, NIRCam acts as the primary science instrument and imager for the JWST and was delivered to NASA in March 2014 for installation and testing in the ISIM. It covers the infrared wavelength range of 0.6 (the edge of the visible spectrum) to 5 microns (the near infrared) and its focal plane assemblies consist of 40 million pixels that operate at 35 Kelvin (-396° F, -238° C).
In addition, NIRCam acts as the telescope's primary mirror-alignment sensor, which keeps the 18 individual, adjustable mirror segments aligned, so it comes under the heading of indispensable.
"NIRCam has to work in order for the James Webb Space Telescope to work," says Alison Nordt, NIRCam program manager at Lockheed Martin. "That's because the alignment of the primary mirror segments depends on NIRCam to determine how to adjust the segments correctly. During instrument testing at Lockheed Martin, we tested the camera in two parts, and the optical performance was excellent. Now it has been tested at a higher level of assembly — both before and after flight-like vibration — and the optical performance is extremely stable."
According to Lockheed, NIRCam's final cryogenic testing came off better than expected. In terms of accuracy, it performed between 32 and 52 nm (52 nm is a hundredth the width of a human cell), which is better than the required 93 nm. In addition, its optical performance remained "rock-steady" between tests.
Intended as the successor to the Hubble and Spitzer Space Telescopes, the JWST will be the most powerful space telescope ever constructed when it lifts off in October 2018. The NASA-led international project is being run in cooperation with ESA and the Canadian Space Agency and recently completed assembly of the JWST's primary mirror.
Source: Lockheed Martin
