Human Impact Exposure

The Human Response to Acceleration and Impact Exposure

The human response to overexposure to acceleration can include G-LOC, redding-out, and greying-out, and in addition to endangering rigid skeletal structures, prolonged exposure can affect circulation and rupture blood vessels. Acceleration imposes strict limitations on safety, and under severe exposure humans and hardware can quite literally break.

Acceleration is often measured in units of “g”, with 1 g equal to what is experienced due to gravity at earth’s surface (9.8 m/s^2). For reference, astronauts sustain 3 to 4 g during launch, but the limits of human tolerance depend on multiple factors, including magnitude, direction and rate of change. Like force, acceleration is a vector, so direction really does matter, and what a person can withstand in the forward-facing direction might be entirely different from what they will tolerate in the vertical.