The Jet Propulsion Laboratory (JPL) used the same antennas built for Project Echo to conduct radar experiments to determine Venus’ distance from the Earth, as well as the value of an astronomical unit (AU). Since Venus was much further away than the Moon, some modifications were performed to the existing antennas, like the increase of power output (from 10 to 13 kilowatts). JPL was interested in determining the distance to Venus because the upcoming mission (Mariner) would explorer the planets. The first signal to and from Venus completed the round trip of 113 million kilometers in about six and half minutes. From March until May, JPL collected 238 hours of recorded radar data about Venus.
› To See the Unseen, A History of Planetary Radar Astronomy› SCaN History of the 1960’s