Tasking cadence: why it decides whether you catch an intermittent methane leak
Tasking cadence is the interval between successive satellite passes you can order over a specific site, not the general revisit frequency of the constellation as a whole. The two numbers get conflated constantly in vendor decks, and the gap between them is exactly where intermittent leaks hide.
Revisit frequency vs tasking cadence
A constellation's revisit frequency is a physics statement: how often any given point on earth falls under a sensor's swath, assuming nothing else gets in the way. Tasking cadence is the narrower, practical answer: how often you can point a specific instrument at a specific pad and get a usable scene back. Cloud cover, competing tasking requests, sun angle for SWIR retrievals, and the sensor's own duty cycle all eat into that number. A constellation marketed as "daily revisit" can deliver a tasking cadence closer to twice a week for a given coordinate once you account for all of that. For someone trying to catch a leak, cadence is the one number that actually matters.
Why annual flyovers miss intermittent sources
Most methane sources at a well pad aren't steady-state. Pneumatic controllers cycle. Liquids unloading happens in bursts. A stuck valve might vent for six hours during a maintenance shift and get fixed before the next crew rotation ever sees it. A single annual aerial survey, flown once a year under contract, has roughly a 1-in-365 shot at landing on the day a given intermittent source happens to be active. That's sampling math, applied to a source that's rarely on.
It's the same gap that makes basin-level advisories frustrating to work with. A regional notice can tell you methane concentration spiked somewhere in a basin last Tuesday. It can't tell you which of the forty pads in that basin was the source, and if the source was intermittent, the plume may already be gone by the time a follow-up flight gets scheduled.
What daily tasking buys you
Move from one pass a year to daily tasking, tasking-dependent since cloud cover and competing requests still apply, and the sampling problem inverts. Instead of one roll of the dice per year, you're closer to one roll per day. A source that's active for a few hours every week or two starts showing up in the record instead of slipping between flights. The question changes from "did the annual survey happen to catch anything" to "is this specific pad emitting today," which you can act on with a field call to the ops team or a note in a fund's emissions file.
Cadence alone doesn't solve attribution. You still need a sensor resolving the SWIR absorption signature of a plume at a resolution tight enough to tie it back to a site boundary rather than a county. But cadence sets the ceiling on what attribution can even find. A plume that was never there on the day of the pass can't be attributed to anything.
The question worth asking a vendor
Don't ask a provider "what's your revisit frequency" and stop there. Ask what the realistic tasking cadence looks like for the coordinates of your actual sites, and what happens to that cadence during cloud season in your basin. The answer tells you if the tool can catch a leak that runs for an afternoon, or only confirms the ones already chronic enough to still be running when the next scheduled pass arrives.
Methane Plume Map is built around that per-site question, with a map you can point at a specific pad and ask whether it's emitting today, delivered daily where tasking allows. If intermittent sources are the ones costing you sleep, that's the gap worth closing first.