Why is calibration drift a concern for long-duration missions?

• A. Drift is not a concern.
• B. Sensor response changes over time cause bias; drift leads to incorrect readings; requires periodic calibration or in-flight calibration methods.
• C. Calibration drift only occurs in testing.
• D. Drift improves accuracy over time.

Answer: (B)

Calibration drift is the gradual change in a sensor’s output that isn’t tied to the actual quantity being measured. In long-duration missions, sensors age and are exposed to varying temperatures, radiation, and onboard electronics stress, all of which slowly shift the sensor’s response. This creates bias in the readings, so data can become systematically off from true values if left unchecked. Because even small shifts accumulate over time, accuracy and trust in critical measurements—like navigation, attitude, or science data—can degrade. To keep results reliable, recalibration is scheduled periodically or done in flight using known references, redundant sensors, or self-calibration techniques.

Drift is not something to ignore; it doesn’t improve accuracy, and it doesn’t only occur during testing.