Russian exploration of Venus: past and prospects

Secure methods of the cost-effective flights to Venus and the passage of its gravity sphere are necessary to increase the amount of scientific and service equipment on board spacecraft and effectively exploration of the solar system. The results of the modern methods of ballistics design using for interplanetary flights to Venus are given with the purpose of entering the Venusian satellite orbit and for the landing on its surface. The main attention devotes to the construction of the launch windows and to the calculation of the reachability areas of the descent vehicle on the surface of Venus.