Lunar and Planetary Institute

Apollo 15 Mission

Science Experiments - Bistatic Radar Experiment

The Bistatic Radar Experiment measured the scattering of radar waves from the lunar surface.

Photograph of the Apollo 15 Command and Service Modules taken from the Lunar Module This photograph of the Apollo 15 Command and Service Modules was taken from the Lunar Module. The high-gain anntenna, part of the spacecraft's communication system, is visible on the left side of the Service Module. This anntena was also used in the Bistatic Radar Experiment.

The Bistatic Radar Experiment was performed on Apollo 14, 15, and 16. In this experiment, radio waves were transmitted from the Command and Service Modules, bounced off the Moon's surface, and then recorded at tracking stations in California. The properties of the waves recorded on Earth were analyzed to determine the roughness of the Moon's surface in the region where the radio beam was reflected. In addition, the electrical properties of the lunar surface (specifically, the dielectric constant of the lunar rocks) were also determined. The region analyzed by this method was about 10 kilometers across, and the spot being studied scanned across the Moon's surface as the spacecraft moved in its orbit.