The satellite's instrument is a high-frame-rate ultraviolet imaging spectrometer, providing one image per second at 0.3 arcsecond spatial resolution and sub-ångström spectral resolution.
NASA announced on 19 June 2009 that IRIS was selected from six small explorer mission candidates for further study, along with the Gravity and Extreme Magnetism (GEMS) space observatory.
The spacecraft arrived at Vandenberg Air Force Base, California, on 16 April 2013 and was successfully launched on 27 June 2013 by a Pegasus-XL rocket. IRIS achieved first light on 17 July 2013. NASA noted, "IRIS's first images showed a multitude of thin, fibril-like structures that have never been seen before, revealing enormous contrasts in density and temperature occur throughout this region even between neighboring loops that are only a few hundred miles apart." On 31 October 2013, calibrated IRIS data and images were released on the project website. A preprint describing the satellite and initial data has been released on the arXiv.
^De Pontieu, B.; Title, A. M.; Lemen, J.; Kushner, G. D.; Akin, D. J.; Allard, B.; Berger, T.; Boerner, P. et al. (2014). "The Interface Region Imaging Spectrograph (IRIS)". arXiv:1401.2491 [astro-ph].
Payloads are separated by bullets ( · ), launches by pipes ( | ). Manned flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets).