How to read this
Drop in a flight log and Debrief reads it into one flight: the headline numbers and the curves that matter, with the events marked on them. It auto-detects the loggers it knows; for anything else it falls back to a column mapper, so any logger that can export a CSV works.
- Apogee is the real peak — a short median filter removes the single-sample jump an ejection charge punches into a barometric trace, so a deployment pop can't fake a higher altitude.
- Velocity and acceleration come straight from the device when it logged them; otherwise they're derived from altitude and clearly marked as such.
- Events — liftoff, burnout, apogee, main deploy and landing — are detected and drawn on every chart. Each is tagged measured or derived so nothing looks more certain than it is.
- Units toggle between feet and meters (top-right of the report); acceleration is always in g. Your choice is remembered and rides in the URL.
- Share — Share link copies a link with the whole flight encoded inside it. The data rides in the link itself and is decoded in the recipient's browser — it never touches a server. A very large flight can be too big for a link; save the chart or summary instead.
- Privacy — the file is parsed in this browser and never leaves your device. There is no upload and no server.
Drop a flight log here
CSV or text export from your altimeter — or any logger's CSV.
Your file is read in this browser and never uploaded — parsing and analysis happen entirely on your device.
Where the numbers come from
Every logger is different, so Debrief reads each file into one common shape — a time base plus named channels in SI units — and runs the same analysis on all of them. Here is how each number is worked out, and where it can be wrong.
Ground baseline & altitude
Altitude is taken from the logger's own altitude channel where it has one, or derived from barometric pressure with the standard atmosphere when it only logs pressure. Either way the pad level is set from the median of the opening samples, so altitude reads zero on the rail and everything after is height above the pad (AGL). Barometric altitude drifts with weather and is disturbed by a rocket's own airflow near the airframe — treat it as good to a few meters, not centimeters.
Apogee
The peak of a spike-cleaned altitude trace. A short median filter removes the one- or two-sample jumps that an ejection charge's pressure pulse punches into a baro trace, which is exactly what makes a naïve “highest reading” report an apogee that never happened. The filter is narrow enough to leave the true peak untouched.
Velocity & max velocity
If the device logged a velocity (an accelerometer-integrated speed is best through the high-speed boost), Debrief uses it. Otherwise velocity is the time-derivative of the cleaned altitude, smoothed to a window sized to the file's own sample rate so a noisy baro trace doesn't turn into a noisier velocity. Derived velocity is reliable through the slower parts of a flight and softer at peak speed; it's labeled wherever it appears.
Acceleration
Used directly from the accelerometer when present, otherwise derived from velocity. Max acceleration is read over the boost; max deceleration over the same ascent.
Liftoff & burnout
With an accelerometer, liftoff is the first sustained kick above about 2 g and burnout is where axial acceleration falls back through zero — the end of thrust. With baro only, liftoff is the first real climb off the pad and burnout is taken at peak velocity, which is where a coasting rocket's speed turns over.
Deployments & descent rates
After apogee, Debrief looks for a clear, sustained drop in descent speed — a fast drogue descent giving way to a slow main — and marks it as the main deployment. Descent rates are the average vertical speed over each phase. A single-deploy flight shows one descent rate and no separate main event. Marginal transitions are left unmarked rather than guessed.
Mach & temperature
The speed of sound is computed from the ground temperature where the logger records it, falling back to a 15 °C standard day. Mach is max velocity over that speed of sound, so on a hot or cold day expect it to shift slightly.
Formats & privacy
Altus Metrum (AltOS), PerfectFlite (StratoLogger / Pnut), Eggtimer and Featherweight (Raven via the Interface Program, and Blue Raven) files are recognized and parsed automatically; more loggers are being added, and the generic-CSV mapper — which also reads header-less exports — covers the rest in the meantime. Files are read with the browser's own file API and never uploaded — the analysis you see ran entirely on your device. For live motor stock and pricing, see the HPR Motor Finder.