Performance requirements and goals for the MIRI imaging are:

1.) Imaging shall extend from 5 to 27 microns in at least 12 spectral bands

2.) Images shall be diffraction limited at 5 microns and shall be critically sampled at 6(TBR) microns

3.) The imaging field of view shall be at least equivalent to 1.5 x 1.5 arcmin

4.) The imager shall be natural background limited between 5 and 10 microns

5.) The imager shall be able to measure point sources at least as bright as 4mJy at 10 microns

6.) The imager shall include a low resolution spectroscopic capability (R ~ 100) from 5 to 10 microns

7.) 'Simple' coronagraphs shall be provided, simple in the sense that they will not require additional mechanisms.

Performance requirements and goals for the MIRI spectroscopy are:

1.) Spectroscopy shall be provided between 5 and 27 microns, with extension to 28.3 microns as a goal

2.) The nominal spectroscopic resolution shall be  ~3000 (or more) from 5 to 10 microns, and shall be reduced by diffraction to no less than 1400 at 20 microns

3.) The spectrometer shall include integral field units with fields of view of 2 arcsec, with fields of view of 3 arcsec as a goal

4.) The nominal pixel size in the spectrometer shall be 0.2 arcsec

These requirements were set by an international team (The Mid-Infrared Steering Committee) in July, 2001, and have formed the basis for the subsequent design definition.