The next steps for MIRI
14 Jul 2017



Testing is underway for the Mid-Infrared Instrument (MIRI), the coldest instrument on the James Webb Space Telescope (JWST).

​The installation of MIRI into the instrument module​

​The installation of MIRI into the instrument module​​

Credit: NASA

The advanced cooler for the​ instrument (its own refrigerator) is currently undergoing performance testing at the NASA Jet Propulsion Laboratory (JPL) in California.

MIRI is one of the key instruments currently being built for NASA’s JWST, which, once it is launched in 2018, will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

The cooler is very complex and needs components spread throughout the huge telescope to help reduce the temperature of the instrument to a super cold -267degC. The current tests at JPL are using a spare cooler and a prototype MIRI; this was specially adapted by the European MIRI team, including STFC RAL Space, to get a better understanding of how all these components behave when connected together.

Engineers from STFC form part of the test team at JPL who are putting the cooler system through its paces to see how it functions.

The MIRI Lead Thermal Engineer at STFC, Bryan Shaughnessy said “We’re calling this an end-to-end test. It is a little like perfecting a recipe. We have the ingredients and the techniques and, with a little knowhow and tweaking, we will get the perfect dish. These tests will fine-tune the operational parameters of MIRI.”

MIRI Thermal Engineer at STFC RAL Space Sam Tustain added “The tests have provided an excellent opportunity for the STFC thermal engineering team to learn more about the cooler systems that drive MIRI and to see first-hand how the different components interact with each other.”

The test will give information on how MIRI should operate after JWST is launched in October 2018.

The UK contribution to MIRI is funded by UKSA and ESA.


Notes to Editors


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 has been put through its paces with a series of rigorous environmental test campaigns designed to verify performance and functionality and is now undergoing final testing. at Johnson Space Centre in Houston. The UK team and teams from both the US and Europe travel out at different times to work on shifts with the NASA team and the other JWST Science Instrument teams.


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 involvemen​t 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 is at the heart of UK efforts to explore and benefit from space. It is responsible for all strategic decisions on the UK civil space programme and provides a clear, single voice for UK space ambitions.

About the European Space Agency

The European Space Agency (ESA) provides Europe’s gateway to space and is an intergovernmental organisation, created in 1975, with the mission to shape the development of Europe’s space capability and ensure that investment in space delivers benefits to the citizens of Europe and the world.​​

For more information please contact: RAL Space Enquiries