diff --git a/lib/sensors.ks b/lib/sensors.ks
index 5e74605..cbebfa2 100644
--- a/lib/sensors.ks
+++ b/lib/sensors.ks
@@ -1,3 +1,5 @@
+// Functions for reading from on-board sensors and performing other ship-local
+// monitoring tasks.
 
 // we rebuild the sensor list with every invocation, because things change
 function buildSensorList {
@@ -52,3 +54,4 @@ function ReadSensor {
 
   return ret.
 }
+