This was the first Soviet attempt at a Venus probe. The probe was successfully launched into Earth orbit with a SL-6/A-2-e (Molniya 8K78) launcher. The launch payload consisted of an Earth orbiting launch platform (Tyazheliy Sputnik 4) and the Venera probe. The fourth stage (a Blok L Zond rocket) was supposed to launch the Venera probe towards a landing on Venus after one Earth orbit but ignition failed, probably due to a fault in the power supply to the guidance system, the PT-200 DC transformer had not been designed to work in a vacuum. The spacecraft and launch platform remained attached in a 212 x 318 km, 64.95 degree inclination, 89.8 minute Earth orbit. Because of its large size (6483 kg), the mission was originally thought by non-Soviet observers to be a failed manned mission, and later was described as a test of an Earth orbiting platform from which an interplanetary probe could be launched. This was the first attempt to launch a spacecraft from a preliminary Earth orbit. The orbit decayed and the spacecraft reentered the Earth's atmosphere on 26 February after 22 days. The Venera probe had a mass of about 645 kg and was based on the M1 (Mars) spacecraft design. It was designed as a Venus atmospheric probe. It carried a 3-axis magnetometer, a variometer (vertical speed indicator), and charged particle monitors. It also carried a small globe which held medallions and other commemorations of the mission. The spacecraft communications were at 66 and 66.2 MHz.