Methane remote sensing?
I found a great paper named Remote Sensing of Particulate Pollution from Space: Have We Reached the Promised Land? and collected some remote sensing instruments doing CH4 measurement in the chart below.       

It contains the information about the satellite, orbit types, instrument and the data time-range.

Satellite       Orbit       Instrument    Years

Nimbus-7        Polar       SAMS          1978-1983     
UARS            L56.9       CLAES         1991-1993     
UARS            L56.9       HALOE         1991-2005     
ADEOS           PS          IMG           1996-1997     
Terra           PS          MOPITT        1999-            
AQUA            PS          AIRS          2002-            
AURA            PS          HRDLS         2003-            
Envisat         PS          SCIAMACHY     2007-