“我们相信ARJ21是一个很好的项目”——访罗克韦尔·柯林斯公司商务和支线系统部副总裁兼总经理丹尼·海格森

记者：请您介绍一下罗克韦尔·柯林斯公司在ARJ21-700项目中的参与情况。 丹尼·海格森：作为ARJ21-700项目的19家供应商之一，我们负责为ARJ21-700飞机提供一整套的航电设备，其中涵盖了通信、导航、飞控以及监视各个子系统。     

Biomedical problems of EVA support during manned space flight to Mars

Current projects of manned missions to Mars are aimed to their realization in the second-third decades of this century. The purpose of this paper is to determine and review the main biomedical problems, that require a first and foremost decision for safety support of extravehicular activity (EVA) carried out by crewmembers of the Mars expedition. To a number of such problems the authors of the paper attribute a creation of adequate EVA equipment intended, first, for assembly of interplanetary spacecraft on the Earth orbit, performance of maintenance operations and scientific researches on the external surface of spacecraft during interplanetary flight and, secondly, for work on the Mars surface. New generation of space suits with low weight, high mobility and acceptable risk of decompression sickness must be as a central component of EVA equipment. The program for preparation to a Mars expedition also has to include special investigations in order to design the means and methods for a reliable protection of crew against space radiation, to elaborate the approach to medical monitoring and primary medical care during autonomous space mission, to maintain good health condition of crewmembers during EVA under the Mars gravity (0.38 g) after super long-term flight in weightlessness.     

An Enduring Partnership Professional, Cultural, Personat

20 years ago, in September 1987, an adventure began which was unique in aviation/aerospace publishing. That adventure led to a multimedia partnership which has grown stronger every year since 1987 and developed into a lasting friendship and global business alliance that continues today.     

The feasibility of Doppler monitoring during EVA

During extravehicular activities (EVA) outside the spacecraft, astronauts have to work under reduced pressure in a space suit. This pressure reduction induces the risk of decompression sickness (DCS) by the formation of gas bubbles from excess nitrogen dissolved in the organism by breathing air at normal pressure. Under laboratory conditions the gas bubbles moving in the blood stream can be detected by the non-invasive ultrasonic Doppler method. By early detection of excessive bubble formation the development of DCS symptoms may be prevented by early application of preventative measures. The method could also be useful when applied in the space suit in order to compare the results of laboratory tests with operational results, because there is a discrepancy according to the DCS risk of laboratory experiments and actual EVA missions, where no symptoms have been reported yet. A prototype Doppler sensor has been developed and implemented in the Russian Orlan suit. To investigate the feasibility of this method under simulated space conditions, the equipment has been used in a series of 12 thermovacuum chamber tests with suited subjects, where intravenous bubble formation was compared to unsuited control experiments. In more than 50% of the suited tests good Doppler recordings could be achieved. In some cases with unsatisfying results the signal could be improved by breathholding. Although the results do not yet allow any conclusion about a possible difference between suited and unsuited subjects due to the small number of tests performed, the method proved its feasibility for use in EVA suits and should be further developed to enhance the safety of EVA procedures.     

Fatty acid composition of plasma lipids and erythrocyte membranes during simulated extravehicular activity

Ten subjects (from 27 to 41 years) have been participated in 32 experiments. They were decompressed from ground level to 40-35 kPa in altitude chamber when breathed 100% oxygen by mask and performed repeated cycles of exercises (3.0 Kcal/min). The intervals between decompressions were 3-5 days. Plasma lipid and erythrocyte membrane fatty acid composition was evaluated in the fasting venous blood before and immediately after hypobaric exposure. There were 7 cases decompression sickness (DCS). Venous gas bubbles (GB) were detected in 27 cases (84.4%). Any significant changes in the fatty acid composition of erythrocyte membranes and plasma didn't practically induce after the first decompression. However, by the beginning of the second decompression the total lipid level in erythrocyte membranes decreased from 54.6 mg% to 40.4 mg% in group with DCS symptoms and from 51.2 mg% to 35.2 mg% (p<0.05) without DCS symptoms. In group with DCS symptoms a tendency to increased level of saturated fatty acids in erythrocyte membranes (16:0, 18:0), the level of the polyunsaturated linoleic fatty acid (18:2) and arachidonic acid (20:4) tended to be decreased by the beginning of the second decompression. Insignificant changes in blood plasma fatty acid composition was observed in both groups. The obtained biochemical data that indicated the simulated extravehicular activity (EVA) condition is accompanied by the certain changes in the blood lipid metabolism, structural and functional state of erythrocyte membranes, which are reversible. The most pronounced changes are found in subjects with DCS symptoms.     

The main results of EVA medical support on the Mir Space Station

The aim of this paper is to review the main results of medical support of 78 two-person extravehicular activities (EVAs) which have been conducted in the Mir Space Program. Thirty-six male crewmembers participated in these EVAs. Maximum length of a space walk was equal to 7 h 14 min. The total duration of all space walks reached 717.1 man-hours. The maximum frequency of EVA's execution was 10 per year. Most of the EVAs (67) have been performed at mission elapsed time ranging from 31 to 180 days. The oxygen atmosphere of the Orlan space suit with a pressure of 40 kPa in combination with the normobaric cabin environment and a short (30 min) oxygen prebreathe protocol have minimized the risk of decompression sickness (DCS). There has been no incidence of DCS during performed EVAs. At the peak activity, metabolic rates and heart rates increased up to 9.9-13 kcal/min and 150-174 min-1, respectively. The medical problems have centred on feeling of moderate overcooling during a rest period in a shadow after the high physical loads, episodes with tachycardia accompanied by cardiac rhythm disorders at the moments of emotional stress, pains in the muscles and general fatigue after the end of a hard EVA. All of the EVAs have been completed safely.