Answer
No, Hermaszewski's mission to space was not a solo mission. He was part of the Soyuz 30 crew, which also included Pyotr Klimuk, the commander of the mission. The Soyuz 30 mission was launched on June 27, 1978, and successfully docked with the Salyut 6 space station. Hermaszewski and Klimuk spent two days aboard the space station, conducting experiments and observing Earth from space.