Launch from the Baikonur Cosmodrome; landing 300 km west of Tselinograd.

Soyuz 30 was the second Interkosmos mission. Miroslaw Hermaszewski became the first cosmonaut from Poland. Following a one day solo flight Soyuz 30 docked with the Salyut 6 space station on June 28, 1978 and the crew performed common work with the second resident crew.

Experiments on the field of materials science were performed. Photography of the Earth surface and study of the aurora borealis were done together with the second resident crew. The activities of the Soyuz 30 crew, however, were severely curtailed so as not to interfere with the Soyuz 29 crew. On the Soyuz 29 crew's rest day, the international crew had to stay in their Soyuz to perform their experiments.

Nevertheless, Miroslaw Hermaszewski conducted many experiments. One was crystallization experiments which produced 47 grams of cadmium tellurium mercury semiconductors for use by infra-red detectors on board the station. The yield was far greater - 50% compared to 15% - than ground-based experiments. Miroslaw Hermaszewski participated in medical experiments which measured lung capacity and the heart during exercise and in a pressure suit. One experiment, which all four on board the station participated in, was Smak, a taste experiment which sought answers to why some food was less palatable in weightlessness.