The Mid Infra-Red Instrument (MIRI)

MIRI in the Space Test Chamber
MIRI being prepared for vibration testing

The Mid Infra-Red Instrument (MIRI) is being designed, built, and tested by a European Consortium of 10 member countries led by the UK in partnership with NASA Jet Propulsion Laboratory. The European contribution is led by Dr Gillian Wright MBE of the UK Astronomy Technology Centre in Edinburgh. The US contribution is led by Dr George Rieke of the University of Arizona.

The UK’s lead role in the instrument involves taking responsibility for the overall science performance, the mechanical, thermal and optical design, along with the assembly, integration, testing and calibration . These roles are shared between the UK institutions in the partnership as follows:

UK Astronomy Technology Centre (UKATC)

Overall science lead for the instrument; responsible for the overall instrument optical design and providing the spectrometer pre-optic subsystem.

STFC Rutherford Appleton Laboratory (RAL)

Responsible for overall instrument thermal design and analysis and production of all thermal hardware; assembly, integration, testing & verification of instrument including provision of all necessary bespoke test facilities; instrument ground calibration; consortium contamination control leadership role.

University of Leicester

Responsible for instrument overall mechanical design and analysis; provision of instrument primary structure (in partnership with Danish National Space Centre); provision of mechanical ground support equipment.

EADS Astrium

MIRI being assembled in the AIV Facility
MIRI being assembled in the AIV Facility

Overall project management and engineering leadership role; systems engineering; overall instrument product assurance leadership.

The major subsystems of the instrument are designed built and testing at the various institutes across Europe and the United States. These major subsystems are delivered to RAL where they are put together to form a complete science instrument. These major subsystems are:

  • The Input Optics and Calibration Unit (IOC)
    Provided by Centre Spatial Liege (CSL) in Belgium. This unit takes the light from the telescope and divides and correctly formats the beam for the Imager and Spectrometer subsystems. It also contains a Contamination Control Cover mechanism (provides by the Paul Scherrer Institute (PSI) in Switzerland) which ensure the sensitive optical surface stay clean throughout the mission.

  • The Mid-Infrared Imager (MIRIM)
    Provided by CEA, Saclay, France. This is the camera for the instrument which will produce the imagery data. This unit contains an 18 position filter wheel mechanism (provided by MPIA, Heidelberg, Germany) in order to allow images to be captured at different wavelength ranges. This unit also houses a coronagraph which is used to block out the bright light sources so that nearby dim objects can be seen. This will be used to observe the areas around stars so that the much dimmer planets and dust clouds can be studied without the light from the main star blinding the instrument.

  • The Spectrometer Pre-Optics (SPO)
    Provided by the UKATC. This is the first unit of the spectrometer which splits the incoming light into its component wavelengths. This allows scientists to examine the chemical composition of gas clouds, stars and even planetary atmospheres. The SPO includes two dichroic and grating wheel mechanisms (provided by MPIA, Heidelberg, Germany) which are used to select which part of the incoming light the spectrometer measure. 

  • The Spectrometer Main Optics (SMOs)
    Provided by Astron, Netherlands. There are two of these units, one takes the shorter wavelength range light from the spectrometer (5 – 12 microns) and the other takes the longer wavelength (12 – 28 microns) light and focuses it correctly onto the detectors.

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