  soyuz 18 (, union 18) was a 1975 soviet manned mission to salyut 4, the second and final crew to man the space station. pyotr klimuk and vitali sevastyanov set a new soviet space endurance record of 63 days and the mark for most people in space simultaneously (seven) was tied during the mission. ==crew==  ===backup crew===  ==mission parameters== *mass:  *perigee:  *apogee:  *inclination: 51.7Â° *period: 88.6 minutes ==mission highlights== the soyuz 18 crew were the back-up crew for the failed soyuz 18a mission, carried out that mission's objectives, and continued the work of the previous [[so
1975_in_spaceflight 1975_in_the_Soviet_Union Manned_Soyuz_missions Spacecraft_launched_in_1975