Your last mission is restored automatically on refresh.
Units
Launch Location
or click the map to place a launch pin
Launch Date / Time
3-D drift path currently supports GFS / Auto / Archive (gridded field). ECMWF/ICON/HRRR/GEFS/RAP are single-column for now — gridded support coming.
Ascent
Rate is the climb rate AT THE LAUNCH SITE. It rises with
altitude as the balloon expands; clear sun adds solar superheat (more lift, lower
burst). Burst altitude is solved, not entered.
Payload
Valve/pipe that falls with the burst balloon. The balloon
latex mass is added automatically; together they set the remnant fall footprint.
Cutaway
Altitude where the Apollo releases. The empty balloon then keeps climbing on its own to its natural burst, where the balloon + ~1 lb valve mechanism falls back (shown as the landing scatter). Leave blank to model no release (balloon rides to natural burst). Natural burst comes from the fill, not the release altitude — it auto-fills here after each Predict.
Fill Calculator
Sun-warmed tanks read higher PSI for the same gas — set the temperature you read the gauge at. Parallel = all tanks drawn to one shared end-of-fill PSI.
Tanks (fill order)
K = K-tank (~49 L) | T = T-bottle (~122 L)
Constraint Circle
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Basemap
KML Overlay
Dispersion
Past dates only (archived winds, 2021+). One path per day; capped at 45 days. Each new date ≈ 30 s to fetch (then cached).