Luna 9, internal designation Ye-6 No.13, was an uncrewed space mission of the Soviet Union's Luna programme. On 3 February 1966, the Luna 9 spacecraft became the first spacecraft to achieve a survivable landing on the celestial body.
Spacecraft
The lander had a mass of. It used a landing bag to survive the impact speed of. It was a hermetically sealed container with radio equipment, a program timing device, heat control systems, scientific apparatus, power sources, and a television system.
At an altitude of from the Moon, the spacecraft was oriented for the firing of its retrorockets and its spin was stopped in preparation for landing. From this moment the orientation of the spacecraft was supported by measurements of directions to the Sun and the Earth using an optomechanical system. At above the lunar surface, the radar altimeter triggered the jettison of the side modules, the inflation of the airbags and the firing of the retro rockets. Approximately at from the surface, the main retrorocket was turned off by the integrator of an acceleration having reached the planned velocity of the braking manoeuver. The four outrigger engines were used to slow the craft. Approximately above the lunar surface, a contact sensor touched the ground triggering the engines to be shut down and the landing capsule to be ejected. The craft landed at The spacecraft bounced several times before coming to rest in Oceanus Procellarum west of Reiner and Marius craters at approximately 7.08 N, 64.37 W on 3 February 1966 at 18:45:30 GMT. The spacecraft was developed in the design bureau then known as OKB-1, under Chief DesignerSergei Korolev. The first 11 Luna missions were unsuccessful for a variety of reasons. At that time the project was transferred to Lavochkin design bureau since OKB-1 was busy with a manned expedition to the Moon. Luna 9 was the twelfth attempt at a soft-landing by the Soviet Union; it was also the first successful deep space probe built by the Lavochkin design bureau, which ultimately would design and build almost all Soviet lunar and interplanetary spacecraft. All operations prior to landing occurred without fault, and the spheroid ALS capsule landed on the Moon at 18:45:30 GMT on 3 February 1966 west of the craters Reiner and Marius in the Ocean of Storms. Approximately five minutes after touchdown, Luna 9 began transmitting data to Earth, but it was seven hours before the probe began sending the first of nine images of the surface of the Moon.
Surface operations
Approximately 250 seconds after landing in the Oceanus Procellarum, four petals that covered the top half of the spacecraft opened outward for increased stability. The television camera system began a photographic survey of the lunar environment. Seven radio sessions with a total of 8 hours and 5 minutes were transmitted, as well as three series of TV pictures. After assembly the photographs gave a panoramic view of the immediate lunar surface, comprising views of nearby rocks and of the horizon, away. The pictures from Luna 9 were not released immediately by the Soviet authorities, but scientists at Jodrell Bank Observatory in England, which was monitoring the craft, noticed that the signal format used was identical to the internationally agreed Radiofax system used by newspapers for transmitting pictures. The Daily Express rushed a suitable receiver to the Observatory and the pictures from Luna 9 were decoded and published worldwide. The BBC speculated that the spacecraft's designers deliberately fitted the probe with equipment conforming to the standard, to enable reception of the pictures by Jodrell Bank. The radiation detector, the only scientific instrument on board, measured dosage of 30 millirads per day. The mission also determined that a spacecraft would not sink into the lunar dust; that the ground could support a lander. The last contact with the spacecraft was at 22:55 GMT on 6 February 1966.
