Cosmos 1887 carried a payload of biological and radiation physics experiments from nine countries. The landing was several hundred miles from the expected recovery site, which resulted in considerable difficulties. The biological payload on the spacecraft included two primates, ten rats, fruit flies, grasshoppers, beetles, guppies, Hynobiidae, Chlorella ciliates, newts and corn. More than 50 NASA-sponsored scientists were involved in conducting the 33 U.S. experiments onboard. One of these experiments, a study of radiation levels in the space environment, did not require the use of any biological subjects. The U.S. conducted only one experiment on the primates flown on the Biosatellite. The remaining U.S. experiments were performed on tissue samples from five of the flight rats. A number of these experiments were extensions of the studies conducted on the Spacelab-3 mission in April 1985. The other countries involved in conducting experiments on the mission were the Soviet Union, Poland, Czechoslovakia, the German Democratic Republic, France, Romania, Bulgaria and Hungary. The European Space Agency also sponsored some experiments. The U.S. was responsible for developing flight and ground-based hardware, verifying testing of hardware and experiment procedures, developing rat tissue sampling procedures, and transferring tissues and data from the Soviet Union after the flight. One of the mission's noteworthy features was the rat biospecimen sharing program, which allowed a great number of rat tissue samples to be analysed. The objective of the U.S. experiments was to investigate the effect of microgravity on various body systems. The primate experiment was designed to study the growth and development of the peripheral skeleton. Rat studies encompassed a broad array of disciplines. The effects of microgravity on cardiac, liver, small intestine and bone tissue, liver function, skeletal growth, hormone levels and metabolism were studied using various approaches. Other studies investigated changes in the immune, nervous and reproductive systems, in muscle and connective tissue and in skeletal and mineral homeostasis. Another experiment was conducted to evaluate radiation exposure during the flight and to measure the shielding effectiveness of the spacecraft. Ten 12-week-old male specific pathogen free Wistar rats were flown in the Rodent-BIOS. Two rhesus macaques (Macaca mulatta) named Drema and Yerosha occupied the Primate-BIOS.