Kosmos 146 , also known as Soyuz 7K-L1 No. 2P, was a Soviet test spacecraft precursor to the Zond series, launched from the Baikonur Cosmodrome aboard the inaugural flight of the Proton-K rocket, an improved version of the Proton, which had been launched four times before.

The spacecraft was designed to launch a crew from the Earth to conduct a flyby of the Moon and return to Earth. The primary focus was a