Three Mechanisms for Webb’s Scientific Instruments
Furthermore, RUAG Space was responsible for three crucial mechanisms for two of the telescope's four scientific instruments. Two high-precision mechanisms for the telescope’s “super eye” called NIRSpec were developed, built and tested by RUAG Space’s site in Vienna, Austria. This includes the mechanical support structures and special ball bearings of the two filter systems referred to as the instrument’s Filter Wheel Assembly. The 200-kilogram “super eye” – one of the two European contributions to the mission – can detect faintest infrared radiation from the most distant galaxies. Designed to observe 100 objects simultaneously, the NIRSpec will be the first spectrograph in space that has this remarkable multi-object capability.
An extremely versatile instrument, the second European instrument “MIRI” (Mid Infrared Range Instrument), will support all four of JWST’s science themes (see box). The instrument’s Contamination Control Cover was developed by RUAG Space in Zurich, Switzerland, and delivered in 2008. It will protect MIRI against external contamination during the cooldown phase of the tests and after the launch. Additionally, this cryo-mechanism acts as an optical shutter for the instrument to allow on-board calibration and to protect the detectors against bright objects. MIRI will help to see the first generations of galaxies born after the Big Bang.
Crucial Products for A Successful Launch
During assembly and before the JWST finally launches on board an Ariane 5 rocket, a rotating and tilting device developed and produced by RUAG Space in Vienna, enables engineers to work on the telescope from all sides. Depending on the requirements, the trolley moves the telescope to a vertical or horizontal position. RUAG Space has already delivered more than 80 so-called "multipurpose trolleys," which can rotate and tilt a satellite, to customers in Europe and the United States.
The top of the Ariane 5 rocket is made of RUAG Space’s payload fairing. It protects the JWST during liftoff and its journey through the atmosphere. The 17-meter-high structure was produced at the company’s site in Emmen, Switzerland. The Webb’s sunshield – as big as a tennis court – was specially engineered to fold up and fit within the 5.4-meter diameter fairing. “Our fairing was custom-made for this precious payload,” says Holger Wentscher, who heads RUAG Space’s Launchers business unit. “New hardware ensures that venting ports around the base of the fairing remain fully open. This will minimize the shock of depressurization when the fairing is jettisoned away from the launch vehicle.”
On its way into space, the launch vehicle is controlled by a RUAG Space on-board computer ("brain"). Once the payload reaches a certain height, the two halves of the payload fairing are separated and jettisoned from the launch vehicle. The corresponding separation system was manufactured by RUAG Space in Linköping, Sweden. At a later stage, this separation system (payload adapter) allows the JWST to be separated from the launch vehicle.
JWST: Studying the Beginning of Galaxies, Stars and Life
Named after James E. Webb, NASA Director between 1961 and 1968, the JWST will directly observe a part of space and time never seen before. Webb will gaze into the epoch when the very first stars and galaxies formed, over 13.5 billion years ago. Ultraviolet and visible light emitted by the very first luminous objects has been stretched or “redshifted” by the universe’s continual expansion and arrives today as infrared light. Webb is designed to “see” this infrared light with unprecedented resolution and sensitivity. The Webb has four scientific missions: finding the earliest stars and galaxies, understanding how galaxies evolved, observing the formation of new stars and solar systems, and scanning Earth’s neighboring planets for their chemical properties and signs of life. The main instrument of the JWST is an infrared telescope with a main reflector 6.5 meters in diameter. Unlike its predecessor Hubble, which observes the universe from a height of a few hundred kilometers above the Earth, the JWST will orbit around a point 1.5 million kilometers from the Earth. This will keep the spacecraft in the same relative position to the Sun and the Earth to keep the telescope's temperature very low behind its large solar shield. This is necessary for the Webb's sensitive instruments to function properly.
Image credit: NASA/Desiree Stover