Two trajectory corrections were made during the flight of Venera 9 and Venera 10. The descent modules separated from the stations two days before the approach to Venus.
On October 22, 1975, the descent module of the Venera-9 station entered the planet's atmosphere at an angle of 20-23°. After descent - first by the parachute and then by means of a braking aerodynamic shield - the DM performed a soft landing on the sunlit but invisible from Earth side of Venus. During the descent, the spacecraft performed several scientific measurements in the planet’s atmosphere, including the measurement of clouds layer thickness, immediately transmitting the obtained data to the orbiter. Two minutes after landing was started the transmission of the TV panorama. These were the world's first photos transmitted from the surface of another planet. src="/upload/medialibrary/820/82004c9014193d96d6daef752e1fee0d.jpg" height="232" title="Венера-9, Венера-10" style="margin-left: 20px;" align="right" data-bx-orig-src="/upload/medialibrary/820/82004c9014193d96d6daef752e1fee0d.jpg">
The image was obtained in visible light by means of a telephotometer, a system resembling the mechanical television in the principle of operation. The Venera-9 landing site was a placer of rather large rocks. The age of the surface of this type could not be great (106-107 years) and, therefore, Venus judged to be a geologically active planet. The Venera-9 and Venera-10 stations were equipped with the instruments for measuring the density of surface rocks and the content of the natural radioactive elements in them. The landing sites of Venera-9 and Venera-10 had the density which was close to 2.8 a/cm3, and according to the content of radioactive elements it was possible to conclude that these rocks were close in composition to basalts - the most widespread eruptive rocks of the Earth's crust. The transmission of information from the descent module lasted for 53 minutes..src="/upload/medialibrary/24d/24db030dded2b158838a62f8668184b5.jpg" height="265" title="Венера-9, Венера-10" style="margin-left: 20px;" align="right" data-bx-orig-src="/upload/medialibrary/24d/24db030dded2b158838a62f8668184b5.jpg">
The Venera-9 orbiter, braking in the pericenter of the flyby trajectory, entered the orbit of the artificial satellite of Venus within a period of ~ 48 hours.
On October 23, 1975 there occurred the separation between the orbital and descent modules of Venera- 10 station with the following withdrawal of the orbital compartment to the flyby trajectory.
On October 25, 1975 the descent module of the automatic station Venera-10 performed the soft landing on the illuminated side of the planet 2200 kms away from the Venera-9 landing site. The temperature and pressure of the surface in the DM landing site were equal to 460°C and 90 atm. The descent module was able to transmit to Earth the TV images of the Venus surface. The time of DM life on the surface of Venus was equal to 65 minutes. In the meantime, the orbital module of the Venera-10 station also entered the Venus orbit.
After the DM separation, the spacecrafts were transferred to the flyby trajectories, and then injected to the orbits of the planet’s artificial satellites. In order to transmit the scientific data, the necessary ballistic scheme was implemented, which provided the required space and mutual positioning of the orbiter and the DM. The Information obtained by each DM was transmitted to its orbital module, which by this time had become the Venus orbit satellite used to transmit it further to Earth.
After the completion of the DMs missions, both orbiters conducted the comprehensive studies of the planet Venus and the near-planetary space, including the cloud cover photographing