[mturmon]

Yes, NASA (JPL) did some of the original work on remote-sensing measurements of methane emitters.

The bulk of the methane emission events displayed on the (excellent) portal you linked come from EMIT, an imaging spectrometer on ISS.

EMIT was made to map ground mineral composition for climate studies, but it does gather a visible-to-IR spectrum across the mid-latitudes at a 60m resolution. This spectrum bears the imprint of any atmospheric methane, allowing them to back out a CH4 concentration from the spectrum as a side product separate from the original mineral-mapping goals.

(Some history: https://news.ycombinator.com/item?id=33427748)