The successful launch of the James Webb Space Telescope (JWST) was a long-awaited event for our Optics team here at SSTL because way back in 2006 we started work on the Integral Field Unit (IFU) for an instrument called NIRSpec (Near InfraRed Spectrograph), one of four science instruments on board the mission - and we have been waiting patiently since then for launch! The optics module we supplied for JWST is highly complex with over 90 mirrors precisely aligned into a module approximately the size of a small shoebox, and it's a key part of NIRSpec. The IFU takes a 1mm2 sample of the scene image and slices the square image into strips which are reassembled into a long linear virtual slit image as input to the spectrometer for projection onto a matrix detector array to be read.
SSTL's optics module for the NIRSpec instrument – the module is approximately the size of a shoebox
JWST can detect infrared light generated by galaxies as they formed more than 13.5 billion years ago, in the aftermath of the Big Bang. Ultraviolet and visible light emitted by those very first luminous objects has been stretched by the universe’s continual expansion into “redshift” infrared light. JWST is designed to detect this infrared light and scientists will use the data to study the origin and evolution of planets and other bodies in our solar system which are too old and too distant for Hubble to observe.
The $10bn James Webb Space Telescope is the follow-on mission to the Hubble Space Telescope and will be positioned 1.5 million kilometres away between the Earth and Sun where the gravitational forces are cancelled. Approximately 2 weeks after launch, JWST will unfold from its launch configuration into its operational configuration with a heat shield that is nearly the size of a tennis court shielding a 6.5m telescope - the biggest telescope ever launched into Space. The telescope is formed after unfurling a set of “petal” mirrors.
The IFU project provided the opportunity for SSTL to utilise state-of-the-art monolithic metal mirrors with complex forms made by single point diamond machining, the whole instrument except for the legs being made from a single billet of aluminium alloy. The design required mastering the problems arising from working at cryogenic temperatures (32Kelvin).
The project was initially managed by acclaimed space scientist and TV presenter Dr Maggie Aderin Pocock.
SSTL supplied the IFU to NIRSPEC prime, Airbus.
JWST is an international collaboration between NASA and its partners, ESA (European Space Agency) and the Canadian Space Agency.