MIRI on the right tracks at NASA Johnson
21 Nov 2017



​​UK scientists and engineers are celebrating following the confirmation that their instrument has performed very well during the cryogenic testing for the James Webb Space Telescope (JWST) at NASA Johnson Space Flight Center in Houston, Texas.

An image of the target at a wavelength of 19.3 microns.



​This is where the Mid Infrared Instrument (MIRI) has been put through its paces under the watchful eye of the consortium team drawn from the European and US institutes who have been taking care of MIRI 24 hours a day over the last four months.

Slices through the ‘data cube’ obtained by the MIRI spectrometer in a single exposure when looking at a test target

Slices through the ‘data cube’ obtained by the MIRI spectrometer in a single exposure when looking at a test target. Left: An image of the target at a wavelength of 19.3 microns. The field is 8.5 arcseconds wide and 7.7 arcseconds high. For comparison, the disk of Neptune is about 2 arcseconds across. Right: A spectral image, covering the wavelength range 19.0 to 19.3 microns along slice AB in the left hand image. Only a small fraction of the full data cube is shown.

Credit: MIRI EC

The tests have taken place in the world renowned Chamber A, famously used in the Apollo moon missions. For these tests the environment of the chamber simulates the extreme space environment in which the telescope will eventually operate.

One of the first tests that MIRI underwent was the cold function tests. The instrument was cooled down to its operational temperature of 6 Kelvin (-267 C). These tests were aimed at verifying that MIRI was still in good working order and that everything was operating as it should following the trip from NASA Goddard Space Flight Center (near Washington) to Johnson earlier in the year. Results confirmed that there have been no changes since the last cold function tests the previous year, which is good news for the team.

A major and significant part of the campaign for MIRI has been the ‘end –to end’ tests so called because it includes both the flight instruments and the telescope optics. The primary aim of these tests was to trial the technique that will be used to align the chain of mirrors which make up the telescope once in orbit and checking the focus and alignment of MIRI.

MIRI Instrument Scientist Alistair Glasse from STFC’s UK Astronomy Technology Centre (UK ATC) explains more about these tests ‘We have data that has been taken using MIRI’s medium resolution spectrometer (or MRS). We can see from the data that it shows an example of the spectral cubes which will allow MIRI MRS to simultaneously measure the spectra of astronomical sources at all points in an image with unprecedented sensitivity.

‘The artificial targets shown in the image are approximately the same angular size as Neptune, with a single exposure sampling the image at 2000 wavelength points across the planetary disk all at the same time. Following the test campaign we know that MIRI is working well, which is the news that we wanted to hear.’

Professor Gillian Wright, MIRI European Principal Investigator said ‘The MIRI team have worked tirelessly throughout the test campaign and we are extremely pleased by the indications that MIRI is performing as it should, we look forward to seeing JWST again once the chamber is opened in the next few weeks. We should not forget that this test campaign has taken place in extremely difficult conditions because of the devastation that Hurricane Harvey inflicted on the area over the summer. Due to the fact that there was a good hurricane contingency plan put in place before the cryogenic tests started, the tests were able to continue with minor disruption. This was due to the dedication of those working at the facility and at other institutes around the World. Indeed, we had team members working around the clock in the UK simultaneously to help ensure that the testing remained on track. We were very mindful that people in the area local to Johnson had lost their homes and livelihood as a result of the hurricane and our thoughts were with them’.

The MIRI European Consortium team members working round the clock at the test facilty at NASA Johnson

The MIRI European Consortium team members working round the clock at the test facilty at NASA Johnson 
Credit: MIRI EC​

Chris Castelli, Director for Programmes at the UK Space Agency, said ‘The UK Space Agency has been funding the work to integrate and test MIRI since the instrument was delivered to NASA in 2012. This has been a team effort across Europe, led by the UK, and we're delighted to see it performing so well in these tests, which have put some of the greatest spacecraft in history through their paces.’

The enormous chamber door will open sometime in the next few weeks and JWST will be visible again. Keep track of this by watching the live Webb telescope web cam.

The UK contribution to MIRI is funded by The UK Space Agency and the European Space Agency (ESA).​

Notes to editors:

The James Webb Space Telescope (JWST)

The James Webb Space Telescope is an infrared observatory, scheduled for launch mid 2019. JWST, which is a joint collaboration between ESA, NASA and the Canadian Space Agency (CSA) will consist of a passively cooled 6.55m aperture telescope, a suite of infrared cameras and a range of other astronomical instruments.

JWST will find the first galaxies that formed in the early Universe, connecting the Big Bang to our own Milky Way Galaxy. JWST will peer through dusty clouds to see stars forming planetary systems, connecting the Milky Way to our own Solar System. JWST’s instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range.

The Mid Infrared Instrument (MIRI)

MIRI is an infrared camera and spectrometer and will operate between wavelengths of 5 to 27 microns, a region which is difficult to observe from the ground. The instrument has several unique advantages; its location in space will remove the blocking and large background noise effects of the atmosphere which limit ground-based telescopes. JWST can be cooled to a very low temperature; this reduces the emission from the telescope and therefore greatly improves its sensitivity. JWST will have a much larger mirror than any other infrared space telescope, giving improved angular resolution.

MIRI was developed in a collaborative effort between scientists and engineers from ten European countries, led by the UK and the Jet Propulsion Laboratory (JPL), with the support of ESA and NASA. The UK team is made up of a partnership between the Science and Technology Facilities Council’s (STFC) UK Astronomy Technology Centre and RAL Space facilities, the University of Leicester and Airbus Defence and Space with funding from the UK Space Agency and ESA.

The Science and Technology Facilities Council (STFC)

STFC is keeping the UK at the forefront of international science and tackling some of the most significant challenges facing society such as meeting our future energy needs, monitoring and understanding climate change, and global security. The Council has a broad science portfolio including supporting UK work in space and ground-based astronomy technologies and research.

UK Astronomy Technology Centre (UK ATC)

Based at the Royal Observatory in Edinburgh and operated by STFC, the UK Astronomy Technology Centre is the national centre for astronomical technology. The UK ATC designs and builds instruments for many of the world’s major telescopes. It also project manages UK and international collaborations and its scientists carry out observational and theoretical research into questions such as the origins of planets and galaxies. The UK ATC has been at the forefront of previous key initiatives at the VLT, including the construction of KMOS (K-band Multi-Object Spectrograph) which enables 24 objects to be observed simultaneously in infrared light.


STFC RAL Space are responsible for the functional testing of MIRI, these are carried out every time the mission completes a test cycle to ensure that MIRI is still working correctly. RAL Space are responsible for the overall thermal design of MIRI and provide support to the test team during cold tests.

RAL Space based at STFC's Rutherford Appleton Laboratory (RAL), carries out an exciting range of world-class space research and technology development. We have significant involvement in over 210 space missions and are at the forefront of UK Space Research. We undertake world-leading space research and technology development, provide space test and ground-based facilities, design and build instruments, analyse and process data and operate S- and X-band ground-station facilities, as well as lead conceptual studies for future missions. We work with space and ground-based groups around the world.

UK Space Agency
The UK Space Agency leads the UK efforts to explore and benefit from space. It works to ensure that our investments in science and technology bring about real benefit to the UK and to our everyday lives. The Agency is responsible for all strategic decisions on the UK civil space programme. As part of the Department for Business, Energy & Industrial Strategy, the UK Space Agency helps realise the government's ambition to grow our industry's share of the global space market to 10% by 2030.

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Sarah-Jane Smart
Communications Lead JWST MIRI for STFC
Mob: +(44) (0) 7837 634683

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