Soyuz-A  Sergei Korolev initially promoted the Soyuz A-B-V circumlunar complex ("7K-9K-11K") concept (also known as L1) in which a two-man craft Soyuz 7K would rendezvous with other components (9K and 11K) in Earth orbit to assemble a lunar excursion vehicle, the components being delivered by the proven R-7 rocket. Besides the Soyuz 7K spacecraft, the complex would feature a Soyuz 9K booster and a Soyuz 11K tanker with twin whip antennas. The 7K would have been equipped with cameras and sensors to study the lunar surface during the flyby, at a distance of 1,000 to 20,000 km from the Moon's surface. Total flight time would have been 7 to 8 days.