a system of circulating fluid was used to distribute the heat load. this system, plus pre-cooling prior to entry, permitted operation of the lander for 53 minutes after landing, at which time radio contact with the orbiter was lost as the orbiter moved out of radio range. during descent, heat dissipation and deceleration were accomplished sequentially by protective hemispheric shells, three parachutes, a disc-shaped drag brake, and a compressible, metal, doughnut-shaped landing cushion. the landing was about from the "venera 10" landing site.