RUSSIAN EXPERIENCE IN THE MEDICAL SUPPORT OF EXTRAVEHICULAR ACTIVITY ONBOARD THE INTERNATIONAL SPACE STATION

摘要

The goal of the paper is to review the main results of medical support of extravehicular activities (EVA) conducted in Russian space suits during the International Space Station (ISS) missions between June 2001 and June 2007. Russian space suits "Orlan" were used for 23 egresses into open space. Each egress was implemented by two crewmembers (46 man/egresses total). The age of EVA participants ranged from 34.6 to 54.6 years old. Among them there were 14 Russian cosmonauts and 12 NASA astronauts. EVAs were performed during period between days 40-168 of a space mission. The average duration of a single spacewalk was 4 h 48 min. The longest spacewalk was equal to 6 h 31 min. The EVA participants spent a total of 199.1 man-hours in open space. To protect spacewalkers against decompression sickness (DCS) in space suits "Orlan" operated at pressure of 40 kPa a 30-min period of pre-EVA denitrogenation procedure in oxygen environment of space suits with an ambient pressure of 73 kPa was used. By technical reasons the duration of oxygen prebreathing prior two spacewalks was prolonged more than two times. Physiological responses of the EVA participants were adequate to the EVA tasks and psychophysiological exertion. During calm periods a metabolic rate was around 1.8-2.0 kcal/min with a heart rate of 51-60 min~(-1). During maximum loading a metabolic rate reached 8.0-9.8 kcal/min with a heart rate of 150-168 min~(-1). In some cases there were episodes of cardiac rhythm disorders, symptoms of negative heat balance, general fatigue during EVA and pains in muscles of upper extremities after the end of EVA. There were no incidents of DCS. All of the EVAs completed safely. An adequate level of physical performance in EVA participants on long-term space missions was maintained by applying an effective set of microgravity countermeasures.