Is there an IRAM satellite that measures thermal radiation at 250 GHz, or was this a ground-based instrument?
The Nature paper by Bertoldi et al. (2006) says:

Our millimetre observations were performed with the Max-Planck Millimeter Bolometer (MAMBO-2) array detector at the IRAM 30 m telescope on Pico Veleta, Spain.

This is a ground-based telescope in the Spanish Sierra Nevada mountains at 2850m to try and get above as much of the precipitable water vapor, which has a very large effect on sub-mm observations, as possible. Its website is here
Since it's common to refer to the Spitzer and its predecessor, the IRAS mission, when discussing far-infrared observations, I suspect the authors typed &quot;IRAM&quot;, thought &quot;IRAS (satellite)&quot; and made a simple typo that was not caught before publication.