Venera 16Venera 16 was part of a two spacecraft mission to Venus. This Soviet Union craft was accompanied by Venera 15. Both unmanned orbiters were to map the surface of Venus using high resolution imaging systems. The spacecraft were identical and based on modifications to the earlier Venera space probes.
Both Venera 15 and 16 were equipped with a Synthetic Aperture Radar (SAR). A radar was necessary in this mission because nothing else would be able to penetrate the dense clouds of Venus. They were also equipped with a radio altimeter dish antenna. Both probes also had large communication dishes which allowed them to send images back to Earth. They were also equipped with fuel tanks, propulsion units and solar panels. The probes consisted of one cylinder, 5 meters long and 6 meters in diameter. At one end was the SAR parabolic dish antenna. On this end there was also the radio altimeter dish antenna. Towards the middle of the cylinder was the large communications dish. Underneath this dish were the fuel tanks and propulsion units. The probes were equipped with on board computers that saved the images until the entire image was complete. That is, as the SAR bounced off signals to the surface and back, it received a little at a time, not in one big map. So, the computer would save the images and later put them together to send to earth. It was like putting together a puzzle. Venera 16 was launched on June 6th 1983, four days after Venera 15. Venera 16 reached Venus' orbit on October 14 1983. At one point in time, in 1984, Venus orbit was at a superior conjunction and moved behind the sun. Thus, the sun was blocking Venus from Earth. Basically, the sun came between Venus and Earth. No transmissions were possible at this time. So, when they regained contact, Venera 16's orbit was turned back 20 degrees so that it could go back and map the area it missed during this time. In eight months, Venera 15 and 16 had mapped the entire northern hemisphere of Venus.