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SCIENCE DIRECT.

doi: 10.1016/SO273-1177(03)00726-9

THE “SCORPION” EXPERIMENT ONBOARD THE INTERNATIONAL SPACE STATION. PRELIMINARY RESULTS.

V. Borisov2, E. Deshevaya4, E. Grachov’, 0. Grigoryan’, I. Tchurilo3, V. Tsetlin4

’ Scobeltsyn Institure of Nuclear Physics, Moscow State University, Vorobyevy gory, Moscow 119992, Russia. 2 Central Research Institute ofMachine Building, 4 Pionerskaya Str., Korolyev 141070, Moscow region, Russia.

3 Rocket-Space Corporation “Energia “, 4a Lenina str., Korolyev 141070, Moscow region, Russia. 4 Institute of Biomedical Problems, Russian Academy of Science, 76a Khoroshovsky sh, Moscow 123007, Russia.

ABSTRACT

The “SCORPION” program onboard the Russian Segment (RS) of the International Space Station (ISS) is designed to carry out complex research of the effects of the near-Earth space parameters on the conditions under which various experiments and operations are being conducted. Special attention in this program was paid to the biological objects onboard the orbital station, e.g. it was found that variation in the number of colony forming units (micromicets and bacteria) correlates with the solar activity and the absorbed dose. The “SCORPION” experiment onboard the RS ISS started in January 2002. It was designed to measure the following parameters inside the space station: the temperature, the relative humidity and the concentration of various gases inside the station; the absorbed doses in different places inside the RS ISS, the fluxes of energetic charged particles, neutrons and gamma-quanta; the vectors of the magnetic field and low-frequency electromagnetic waves. At the same time the growth of micromicets on the samples of various materials was studied. The description of the “SCORPION” experiment and the preliminary results obtained onboard the RS ISS in 2002 are presented. 0 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

INTRODUCTION

At the present stage of space exploration the problem of providing high reliability and durability of the spacecraft and its systems is put in the forefront. Most failures have been caused by the influence of the near-Earth space factors.

The following problems were encountered when the orbital station inner modules were in service. I. The effects of orbital the flight factors on the equipment and construction units. The problem of material reliability calls for investigation of the materials not only in laboratory but also in the

actual space flight conditions under the complex influence of the near-Earth space factors. Neglecting the problems connected with providing electromagnetic compatibility (EMC) and the absence of a

unified approach to EMC can lead to a noticeable number of spacecraft failures (on some estimates up to 10%). No reliable information is available concerning both the influence of different spacecraft systems on the

onboard devices and the influence of electromagnetic radiation of different frequency ranges on the crew. Using new microelectronic devices and highly integrated chips in the space makes the problem of single event

upsets and dose failures in electronic equipment extremely important. II. Behavior of microorganisms onboard the orbital station. Maintaining living conditions suitable for human beings inside the spacecraft provides favorable conditions for

most bacteria and fungi. For such biota representatives as micromicets and bacteria the near-Earth space factors determine the following conditions of life onboard:

l the high constant electromagnetic background determined by the electromagnetic conditions inside and outside the station (particularly, low frequency electromagnetic waves) as well as the magnitude and gradients of the constant magnetic field;

Adv. Space Res. Vol. 32, No. 11, pp. 2373-2378,2003 Q 2003 COSPAR. Published by Elsevier Ltd. All rights reserved Printed in Great Britain 0273-l 177/$30.00 + 0.00

2374 V. Borisov et al.

l the influence of radiation, including the permanent influence of high-energy galactic particles; l the microclimatic conditions (the temperature, the humidity, the concentration of some atmospheric gas

components in different modules); 0 the microgravitation.

RESULTS FROM THE MIR STATION

All the above-mentioned problems are connected with one general factor of the space, namely, the influence of the space radiation. Depending on the phase of the solar activity cycle the power of absorbed dose (PAD) of the ionizing radiation inside the station compartments varies significantly (from lo3 mkGr/day up to lo’-2*102

mkGr/da y) Besides, depending on shielding in various places, the PAD in the station compartments can differ by 2-4 orders, and at different phases of the solar cycle - up to 10 orders. During 15 years of operation of the MIR orbital space station it

0.3 L was found that in the compartments, --I-_lI-*--.--...__-l -.-

5 0” z s 2 t 2 it! k 9 it especially behind the panels, there occurs

osmQI*QI* *cRclrQ, CFFFPW F -*amI bio-contamination of the surfaces by

YEAR micromicets. The dynamics of the average concentration of microorganisms on the

Fig.1. Dynamics of the microbe community onboard the surface of decorative elements of the MIR station according to daily average -power of absorbed dose. CFU - colony forming units.

the coating in the MIR station compartments during operation of the station is shown in

Fig.2. Dependence of the number of cells upon the dose value.

_ .- .--i ._-_._.

Fig. 3. At the left - growth of fungi of Aspergillus niger species in normal conditions. On the right - at chronic irradiation of gamma- radiation. Chronic influence of radiation can change

the properties of microorganisms. Figure 3 represents the photographs of micet colonies of

the Aspergillus niger species in normal conditions and under the influence of chronic irradiation by gamma-rays. One can see that even the appearance of the colony was changed (see Borisov et al. (2002B)). Moreover, the orbital flight conditions significantly alter the metabolic activity of micromicets. In Figure 4 the comparison of the

Figure 1 (see Viktorov et al. (2001)). The maximum quantity is as high as lo6 on 100 cm2, with an average value being - 1 03.

A serious technical problem was that micet colonies were found on insulating materials of electric connections in the radio-electronic and measuring onboard equipment and on the surfaces of cables; moreover, microorganisms showed capability for bio-destruction. Metabolic products of bacteria and fungi can be particularly hazardous to the structural elements and systems of the station.

As shown by laboratory research, the dependence of growth of some biota representatives on the absorbed dose is characterized by amplification of metabolic processes in the cells at small sub-threshold values of radiation doses and destruction of the cells at the doses exceeding the threshold values. This phenomenon is clearly illustrated in Figure 2, in which the number of CFU is given depending on the dose power. One can see that the maximal number is observed when the radiation is several times greater than the average background (see Viktorov et al. (2001)).

The SCORPION Experiment Onhoard the International Space Station 2375

metabolic activity of the standard micromicet cultures and the “on-flight” micromicets is given (see Viktorov et al. (2001)).

PenidlEium Aspergillus Penkilium Rspertaillus sp. chrysogenum niger expsnsum A. versicolor

u STANDARD “ON-FLIGHT”’ (MUSEUM) CULTURES CULTURES {C0LLECTlON OF 1996)

Fig. 4. Comparison of the activities of standard and “on- flight” micromicets.

As it was shown during the whole period of MIR operation, micromicet activity can vary strongly in various intervals of the flight time and micromicets can be nonuniformly distributed in the station volume. For example, some micromicet species were especially active behind the decorative panels, i.e. in places where it was difficult to apply sanitary and anticorrosive protective treatment.

Variations in radiation conditions at different places of microflora habitation at the station can result in difference in microflora population in the station compartments and, as a consequence, in different intensity of bio- destruction processes. Hence, one can expect that variation of the dose values in different compartments of the station, particularly behind the decorative panels where the dose capacity is greatest at any solar activity cycle, should have an effect on population of bio-objects in the station compartments. Similarly, the bio-

destruction activity of such organisms can be expected to be different. There is undoubtedly a danger of the growth of bio-objects being stimulated under the influence of the high-

frequency electromagnetic fields formed in the compartments of the orbital complex by the operation of the radio- electronic and transmitter-receiver equipment as well as by microwave radiation of the space origin.

Numerous sanitary-hygiene researches performed on the earth proved that the electromagnetic background radiation could cause appreciable and dangerous changes in human health, in particular, oppression of the immune system. It was also noted that weak electromagnetic fields could stimulate the growth of microorganisms. The questions about combined effects of electromagnetic fields and radiation doses on biota were also discussed (see, for example, Grigoryev (1995), Uzdensky et al. (1996)).

THE “SCORPION” PROGRAM AND EXPERIMENT ONBOARD THE ISS

For monitoring the parameters of the environment inside the Russian Segment of ISS over the period of 2001- 2006 the complex SCORPION program was accepted, which is to be implemented in several stages (see Borisov et al. (2002A)). During the first stage the multipurpose equipment, whose primary tasks are given in Figure 5, was developed and constructed. Implementation of the first stage of the SCORPION program began in January 2002.

Collection, initial processing and transmission of the scientific information about the physical parameters being measured are carried out using the computer. The general view of the equipment and its unit designation are presented in Figure 6. The equipment for monitoring the conditions inside the compartments of the Russian Segment of the ISS consists of the following measuring blocks:

l the block for detecting fluxes of neutrons, energetic protons and gamma-radiation; l the unit of vibration sensors; l the block for measuring low-frequency waves; l the three-component magnetometer; l the dosimeter blocks; l the block for detecting energetic charged particles (including fluxes of nuclei of the iron group); l the climatic block including sensors of temperature, relative humidity and gas composition of the inside

atmosphere.

2316 V. Borisov ef al.

t+l protons, electrons I

ansornea dose

qamma- __ _

Dara

nenetratiol

ogical ~TI-J earth

~. ,~.,

magnetic field end electromagnetic waves

measurements

conditions mslde

complex influence on:

Fig. 5. Primary goals of equipment for experiment SCORPION.

To study the behavior of microbe community inside RS 1% is one of the primary tasks of the SCORPION experiment, so the plates with the samples of materials that are widely used for internal coatings of the station compartments and the elements of the onboard equipment are included in the equipment structure. The plates with samples are supplied with dosimeter assembly to study in detail the radiation conditions affecting microorganisms in different places of the station. The plates sets are put in three places behind the compartment coating in the RS ISS.

To study the dynamics of bio-contamination of various materials by associations of micromicets and bacteria, one plate of each set is exposed during a measured time and subsequently returned to the Earth to analyze the species composition and to determine the number of microorganisms that contaminate the sample surface.

The SCORPION Experiment Onboard the International Space Station 2377

Fig. 6. Equipment for experiment SCORPION onboard RS ISS.

PRELIMINARY RESULTS

The work of third basic expedition onboard the ISS having been finished, the first plates with the samples were returned to the Earth for the laboratory analysis after an exposition onboard the station since January till May 2002. The zones where the samples were exposited are shown in Figure 7.

As a result of microbiological research the information on the number of viable colony-forming units and species composition of microbe associations, that contaminate the surface of the samples of polymeric materials, was obtained. The obtained results confirmed that there is a tendency for the number of viable microorganism units to increase as the power of the absorbed dose increases, which had been revealed earlier by the analysis of the data on radiation and microbiological conditions onboard the MIR station.

Table 1 presents the data on the number and specific structure of the microorganisms found on the Right board of SM RS ISS

samples of materials returned from the board of the ISS and the data on the absorbed dose measured by

Plate hk2,. PIate NQ3 --L _ __._. - ,.__.~_..

dosimeters on the sample plates exposed onboard the S’, \. . J -. ‘ii,

ISS. No appreciable increase in the number of microorganisms on plate 2 was revealed. \

From the presented data it follows that the highest population of microorganisms was observed on the Plate NW

samples of materials on the plate that was placed where the influence of the absorbed radiation dose was greatest Fig. 7. Allocation of Plates with samples of

as compared to other places. It should be noted that on materials on board ISS.

the samples of materials on plate 2 (with the least absorbed dose being about 2.0 sGr), no fragments of viable microorganisms were found.

It is known that the artificial polymers are hygrophilous because they have free oxygen-containing radicals. The construction of oxygen-containing groups possibly appears during irradiation of artificial polymers in the air, as a result these materials become hygrophilous. This process leads to increasing absorption of moisture and contamination of the materials by micromicets.

2378 V. Borisov et al.

Thus, the result of the performed research confirmed that as the absorbed radiation dose on the surface of materials increases the number of viable fragments of micromicets also increases. The preliminary data indicate that under the action of ionizing radiation the adhesion of micromicets to the surface of artiticial polymers increases.

Table 1. Number and species of microorganisms

[ J% of plate Material 1 Species 1 CFU Absorbed dose,

CONCLUSION

The study of contamination of the materials by bacterial flora revealed no dependence of the number and species composition of bacteria on the type of contaminated samples. Thus, even the preliminary analysis of the first data obtained in the SCORPION experiment onboard the ISS show that bio-contamination of various materials of the coatings and the station parts by associations of microorganisms onboard the ISS has already become an urgent problem now at the beginning stage of the ISS service.

REFERENCES

Borisov, V.V., E.A. Grachev, O.R. Grigoryan, et al., Experiment “SCORPION” onboard ISS, 3rd International Conference & Exhibition Small Satellites: New Technologies, Miniaturization, Eficient Applications in the 21st Century, 2, 195202,2002A.

Borisov, V.V., E.A. Grachev, 0.R Grigoryan, et al., Some aspects of ecological environment onboard orbital stations, 3rd Russian scientific conference “Physical problems of ecology (ecological physics)“, Moscow, 10, 15-22,2002B.

Grigoryev, Yu. G., Bio-effects and possible mechanisms of influence of ultra weak magnetic and electromagnetic fields (Abstract), 2nd International Symposium “Mechanisms of influence of very low doses”, pp 127, Moscow, 1995.

Uzdensky, A. B., and Kutko, 0. Yu., Influence of very low-frequency magnetic field on isolated neural cell: nonlinear dependencies on amplitude and frequency (Abstract), 1st Russian Conference “Problems on human electromagnetic safety - fundamental and applied investigations”, pp 33-34, Moscow, 1996.

Viktorov, A.N., N.A. Novikova, E.A. Deshevaya et al., Results of microbiological researches “Orbital Station MIR”, Moscow, 1, 121-151,2001.

E-mail address of 0. Grigoryan: orgri@srd.sinp.msu.ru Manuscript received 19 October 2002, revised 8 April 2003, accepted 17 April 2003