Apollo-Soyuz

By Marty McDowell

The Apollo-Soyuz mission was the first manned space flight conducted jointly by two nations. The mission started with the Russian Soyuz launch on July 15, 1975, followed by the U.S. Apollo launch on the same day. Docking in space of the two craft occurred on July 17, and joint operations were conducted for two full days. Both spacecraft landed safely and on schedule; the Soyuz landed in the U.S.S.R. on July 21 and Apollo landed near Hawaii on July 24. The United States and the U.S.S.R. achieved a substantial degree of success in (1) obtaining flight experience for rendezvous and docking of manned spacecraft and developing a docking system that would be suitable for use as standard international system, (2) demonstrating inflight intervehicular crew transfer, and (3) conducting a series of science and applications experiments. Twenty-eight science investigations in the fields of Earth resources, Earth gravity, Earth atmosphere, astronomy, solar science, life sciences and space processing were conducted during the mission.

During reentry, the American crew was accidentally exposed to nitrogen tetroxide gas. The potentially harmful nitrogen tetroxide gas resulted from inadvertent reaction control system (RCS) firings and entered the command module through the cabin pressure relief valve, which was opened during landing. As a therapeutic measure, the crew was given 100% oxygen for 15 to 20 minutes aboard the recovery vessel. All crewmen complained of chest tightness, coughing, a burning sensation when breathing and an inability to inhale deeply, but made a full recovery from the gas exposure. The therapy given to the crew potentially affected two life sciences experiments that were conducted by preflight and postflight blood sampling and analysis. Despite this impact, scientifically useful results were obtained in these experiments.

Facts and Figures
		Apollo-Soyuz
			Astronaut Stafford and Cosmonaut Leonov are seen at the hatchway leading from Apollo to the Soyuz. Leonov holds a camera.
	NASA image

Life Experiments

Seven life sciences experiments were conducted during the Apollo-Soyuz flight. Three experiments examined particle radiation effects on living cells, three experiments examined the effects of space flight on the human immune system, and one examined the vestibular system of killifish. More specifically, the effects of cosmic particles on living cells were examined by the observation of the light flash phenomenon that occurs to astronauts during different orbital orientations. The Biostack III German experiment extended the studies of previous flights on the effects of highly charged and energetic (HZE) particles on biological organisms by evaluating the growth and development of plant seeds and animal eggs that were contained in the biostack. The zone-forming fungi experiment, a joint U.S. and U.S.S.R. experiment, was an attempt to observe the real-time mutations caused by HZE particle exposure that might occur in a ring of growing fungal cells.

Space Sciences Experiments

The space sciences experiments that were conducted on the Apollo-Soyuz mission included five astronomy and five Earth studies investigations. The astronomy experiments ranged from soft x-ray observations which focus on objects deep in the galaxy to the crystal activation experiments which had implications for the application of crystal detectors in gamma-ray astronomy. The Earth studies included the ultraviolet absorption experiment which investigated the atomic composition of the upper atmosphere to the study of the Earth's subsurface structure by means of two variations of gravity-field measurements. In addition, the Earth observation and photography experiment examined the surface of the Earth and its land and water regions.

		Artist's concept of the Apollo-Soyuz docking in earth's orbit.
		NASA image

Source: NASA.

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Space References (Videos):
Cosmos. PBS, 2000.
Stephen Hawking's Universe. PBS, 1997.
Hyperspace. BBC, 2002.
Life Beyond Earth PBS, 1999.
The Planets. BBC, 1999.
Understanding The Universe. A&E, 1996.