This was the Soviet Union's second attempt at a planetary probe. The spacecraft was identical to the one launched four days earlier, and was also an attempted Mars probe carrying a magnetometer, cosmic ray counter, plasma-ion trap, and micrometeorite detector. As on the previous attempt, after liftoff the third stage pumps of the SL-6/A-2-e launcher were unable to develop enough thrust to commence ignition. The spacecraft again reached an altitude of 120 km before reentry.