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Sustained airborne presence

Zephyr demonstrated a long flight. Reliable repeated missions remain unverified.

Shown in practiceConfidence: Medium

Last reviewed

What we are looking for

Is extended presence or repeated return of the identified system observed?

Where this applies

Zephyr 8 · 2022 prototype · stratospheric flight

What has been observed

What limits this finding

What we still need to know

Repeatable completion and exact configurations for later flights.

What would change our view

Independent endurance records or a released termination investigation.

What would be enough to confirm it

A documented long flight or repeated returns; preserve the platform and environmental limits.

How this finding has changed

This is the first review. There is no earlier trend to compare it with.

  1. Shown in practice

    Zephyr demonstrated a long flight. Reliable repeated missions remain unverified.

    First review. Initial assessment; no previous cycle for comparison.