Story

Methane detected from afar.
Methane not detected on ground.

Methane produced some distance above ground?

Maybe a tiny lightweight probe that launches a balloon (or lightweight plane) is in order. It doesn't ever have to land (although couldn't the backside of those heatshields easily be made into some nice big antenna dishes?), it could be launched while the heatshield etc. continues its fall. They already have concepts and some work done on both. Suggested names: Cowboy 1, 2, ..., n, better than Fart Fairies (although I would not object to that so now I'm undecided) :D