@north,
This is simply incorrect.
As the stated goal of the mission is:
The science goals of the WMAP broadly dictate that the relative Cosmic Microwave Background (CMB) temperature be measured accurately over the *full sky* with high angular resolution and sensitivity. The overriding priority in the design was the need to control systematic errors in the final maps. The specific goal of WMAP is to map the relative CMB temperature over the *full sky* with an angular resolution of at least 0.3°, a sensitivity of 20 µK per 0.3° square pixel, with systematic artifacts limited to 5 µK per pixel.