It carried two rhesus macaques named Gordyy and Oomka (or Verny and Gordy), ten male rats, and ten newts. The monkey research focused on vestibular and blood flow investigations as well as radiation effects. The newts had part of their front limbs amputated and their crystalline lenses removed to study the possible rate of human recovery from injuries incurred in space. A biocalorimeter monitored energy exchange during the emergence of flies from nymphs; 1500 drosophila flies were carried for this purpose. The payload also included maize seeds, crocuses, and guppies in an aquarium. The mission was recovered after seven days.
Payloads are separated by bullets ( · ), launches by pipes ( | ). Manned flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets).