1.   Because the Thunderbolt did not have its beacon activated, it gave off a distinct radar signature.

2.   The peculiar radar signatures suggested the presence of water ice in the permanently cold shadows of a deep basin near the lunar south pole.

3.   The plane also stopped transmitting a signal from its transponder, which enhances its radar signature and gives controllers information, such as its flight number and altitude.

4.   This involves shaping the superstructure to create angled surfaces which will emit low radar signature.

5.   On one of the passes it picked up the radar signature of ice in the permament shadows of a giant crater on the south pole.