Histories of the Soviet Russian Space Program - Volume 3: Soviet Space Programs, 1971-75 - Facilities and Hardware, Manned and Unmanned, Bioastronautics, Civil and Military by unknow

Author:unknow
Language: eng
Format: azw
Publisher: Progressive Management
Published: 2013-05-21T16:00:00+00:00

Finally, both American astronauts and Soviet cosmonauts have exhibited moderate losses of body weight as a result of spaceflight. Table 4-43 provides a sampling of cosmonaut weight loss in the Soyuz 4-12 series. Decreased body weight is not of a serious nature and is rapidly reversible upon return to Earth.137-138

In summary, the minor organic problems encountered by Soviet and American space crews have been amenable to medical intervention during space missions. As spacecraft have become larger, exercise equipment and medical/first aid supplies have increased the margin of biomedical safety so that orbital flights of up to 84 days have been successfully accomplished. The successful 63 day flight of Soyuz 18/Salyut 4 has further increased the Soviet confidence factor by yet another quantum. At present, there would appear to be no medical contraindications to flights of even longer duration.

IV. LIFE SUPPORT SYSTEMS AND TECHNOLOGY

The life support system of a manned spacecraft is one of its most critical links, for any significant life support failure results in total mission failure. Therefore, the design of the life support system, which includes atmosphere, food and water, and waste disposal subsystems, is carefully predicated upon well-developed empirical data on human energy requirements and waste generation. Thus, a 70 kilogram (144 pound) man aged 25-40 requires about 600 liters of oxygen, 600-800 grams of dry food, and 2.0-2.5 liters of drinking water per day. An additional 5-10 liters of water per day is required for personal hygiene and sanitation during prolonged spaceflights. At the same time, the human metabolism on a daily basis generates about 400-500 liters of carbon dioxide, 2.5-3.0 liters of water in the form of urine and perspiration, and 100-200 grams of solid waste. The life support system must be able not only to satisfy these basic challenges, but must do so on a sustained basis with virtually 100 percent reliability. It is therefore a tribute to bioengineers in both space programs that there has been no significant life support system failure on any of the 31 American or 26 Soviet manned spacecraft flown thus far.139, 140

A. AIR REGENERATION AND SPACE CABIN ECOLOGY

Since the very beginning of the manned spaceflight program, the Russians have used a physical-chemical system for the generation of oxygen and the removal of carbon dioxide. The American program, on the other hand, utilizes fuel cells as the source of oxygen and lithium hydroxide (LiOH) for carbon dioxide removal. The Soviet spacecraft atmosphere is maintained as close to the normal terrestrial value as possible (14.7 psi or 760 mm Hg barometric pressure; about 20 percent oxygen and 80 percent nitrogen), whereas the American spacecraft atmosphere is 100 percent oxygen at 5 psi (259 mm Hg) during the flight. Since the 1967 Apollo fire which occurred during a simulation test, a less flammable 60/40 oxygen/nitrogen mixture at 15 psi (776 mm Hg) is used during the launch phase. Upper and lower limits of cabin atmosphere parameters for Soviet manned spacecraft in the Soyuz/Salyut series are given below:

Barometric Pressure (mm Hg): 710-900.

Oxygen Content (percent): 19-29.

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