What this calculator does
This tool applies the exponential reliability model to convert a constant failure rate and mission time into a survival probability. It returns the chance of no qualifying failure during the mission, not the chance of partial production.
When to use it
Use it for a first-pass mission model when failures are plausibly random over the relevant period and the rate is based on comparable exposure. It is useful for screening duration sensitivity.
Inputs and formula
λ is failure rate per time unit and t is mission duration in that same unit. R(t) = e−λt
Worked example and interpretation
A rate of 0.0002 per hour over a 500-hour mission gives roughly 90.5% survival probability. It does not say which component will fail or quantify downtime after a failure.
Practical notes and limitations
The exponential model assumes a constant hazard rate and independent failure behavior. It is not a good default for wear-out, burn-in, condition-driven degradation, or shared-cause events. Consider a distributional life-data study for those cases.