THE INFLUENCE OF THE SPACE ENVIRONMENT ON THE VITAL ACTIVITY OF BACTERIA

ABSTRACT

The exploration of outer space opens up many problems for humanity. One of them, about which little is known, is the world of microbes inhabiting a spaceship. It is the microorganisms that hold the absolute record for the duration of stay in space. It is they who do not just live on the orbital station, but develop, adapting to the conditions of flight, acquire offspring [1].

The hypothesis of the project: if certain bacteria are placed in a nutrient medium, they will be able to generate an electric current during their life in the space environment.

The novelty of the project consists in the generation of electric current by bacteria on the basis of the CubeSat nanosatellite platform.

In the conditions of open space, microorganisms can be affected by factors such as temperature, UV radiation and cosmic vacuum, cosmic radiation. In the course of the work, a CubeSat 3U nanosatellite with a biocapsule as a payload was developed, the satellite was launched into near space (stratosphere) [2].

Approbation of the work:

1. Russian Scientific and Social program for youth and schoolchildren "Step into the Future", Bauman Moscow State Technical University, Moscow, 2022-2023.;
2. D. I. Mendeleev All-Russian Competition of scientific research works, Moscow, 2023;
3. International Conference of students of the Union State "Talents of the XXI century", Minsk, 2023.
4. Interregional competition of youth projects "VKOSMOS", Kurganinsk, 2022-2023

АННОТАЦИЯ

Освоение космического пространства открывает перед человечеством множество проблем. Одна из них, о которой мало известно – мир микробов, заселяющих космический корабль. Именно микроорганизмам принадлежит абсолютный рекорд длительности пребывания в космосе. Именно они не просто живут на орбитальной станции, а развиваются, приспосабливаясь к условиям полета, обзаводятся потомством [1].

Гипотеза проекта: если определённых бактерий поместить в питательную среду, то они смогут вырабатывать электрический ток в ходе своей жизнедеятельности в условиях космической среды.

Новизна проекта состоит в выработке бактериями электрического тока на базе платформы наноспутника формата CubeSat.

В условиях открытого космоса на микроорганизмы могут действовать такие факторы, как температура, УФ-облучение и космический вакуум, космическая радиация. В ходе работы разработан наноспутник формата CubeSat 3U с биокапсулой в качестве полезной нагрузки, осуществлен запуск спутника в ближний космос (стратосферу) [2].

Апробация работы:

1. Российская научно-социальная программа для молодежи и школьников «Шаг в будущее», МГТУ им. Баумана, г. Москва, 2022-2023 гг.;
2. Всероссийский конкурс научно-исследовательских работ имени    Д. И. Менделеева, г. Москва, 2023 г.;
3. Международная конференция учащихся Союзного государства «Таланты XXI века», г. Минск, 2023 г.
4. Межрегиональный конкурс молодежных проектов «VКОСМОС», г. Курганинск, 2022-2023 г.

Keywords: nanosatellite; CubeSat, near space, stratosphere, microfuel element (MFE).

Ключевые слова: наноспутник; CubeSat, ближний космос, стратосфера, микротопливный элемент.

The more time space objects function, the more space centenarians – bacteria - become. The sources of entry of microorganisms into the habitat of a space object are both astronauts and various cargoes that are constantly delivered on board. Once in new conditions, the microorganism either dies or adapts. Only the most persistent survive. They change their eating habits and learn to live in a new environment for themselves. Once mastered, they can harm the equipment or even cause diseases in the crew.

Getting on various materials, certain types of microorganisms quickly adapt to them and begin their vital activity. As a result, the color of materials may change, mechanical strength, sealing properties, dielectric and other characteristics may decrease.

Currently, the global damage from microbiological damage to polymer materials alone exceeds 2% of the volume of industrial products. For space orbital stations, taking into account the timing of their operation and the requirements for ensuring the reliability and safety of their operation, this problem is very acute.

Bacteria can produce a current during metabolic processes, which has great potential for study. For example, in the treatment of reservoirs and wastewater. The current generated by microorganisms is small, but it can be used to charge sensors and systems that do not require a large amount of energy. Scientists also found out that if you grow microorganisms on magnetite (stone, mineral), the first will give electrons to this mineral, and the second will take away, thereby forming a real live battery.

Work in this area is carried out on board the International Space Station. Scientists have conducted experiments with bacteria in near space more than once. Microbes lived on the surface of the station — both in closed and open containers.

During the Biomex experiment on board the International Space Station, astronauts grew bacteria capable of fighting the negative influence of pathogenic bacteria. It turned out that by-products of metabolism increase the body's resistance to radiation. Such a reaction of bacteria is associated with an increased radioactive background in space, as a result of which they adapted and began to produce more protective substances.

Scientists have developed an experiment to characterize the differences in gene expression between matching strains of liquid suspension cultures grown in space and on Earth. Bacteria that have been exposed to the space environment have increased aggression and resistance to antibiotics. And some of the bacteria have mutated so much that if they were “free”, they would pose a serious threat to the planet.

Similar projects have the following disadvantages: the large size of the spacecraft; it is inconvenient to deliver bacteria on board.

To solve this problem, a project was implemented to study the functioning of microorganisms in extreme conditions. To do this, a CubeSat satellite with bacteria would be prepared and launched into the stratosphere to study the influence of the space environment on them (Figures 1, 2).

Figure 1. Launch of the spacecraft

Figure 2. The trajectory of the satellite

The conditions of the spacecraft's stay in near space are quite severe: low temperatures: up to -60 ⁰C; low pressure: up to 1% of normal pressure; increased radiation: up to 200 µRh/h; increased heat loss coefficient due to strong winds: up to 190 km/h.

During the experiment, data such as: dose of radioactive radiation (µRh/h); voltage (mV) of bio-loading; temperature (⁰C); pressure (Pa) were recorded.

The spacecraft was launched at 17:26; the flight time was 86 minutes; the maximum altitude to which the spacecraft ascended was 24600 m; the spacecraft flew 80,000 m from the launch point; the minimum temperature was -42 ⁰C [3].

During the experiment, such data were obtained from the spacecraft as: the change in the level of absorbed radiation over time (Figure 3).

Figure 3. Graph of changes in the level of absorbed radiation over time

The maximum dose of absorbed radiation was more than 400 µR/h; a change in the radiation level during the ascent to the maximum altitude (Figure 4); a change in temperature during the flight (Figure 5); a change in temperature inside the apparatus depending on the ambient temperature (Figure 6). The graphs clearly demonstrate that due to the radiation of heat, the onboard systems maintained the temperature inside the device above 0 ℃ [4].

Figure 4. A graph of the change in the radiation level during the ascent to the maximum height

Figure 5. Graph of temperature changes during the flight

Figure 6. Graph of temperature changes inside the device depending on the external temperature of the medium

For the experiment, a type of microbial fuel cell (MFE) of a two-chamber membrane-type design was selected. This MFE is a 2-chamber cell, where the anode and cathode volumes are separated by a cation-selective membrane  (Figure 7) [5].

Figure 7. Computer model of the biocapsule

The vertical orientation of the device was used, which is necessary for the correct loading of the chambers with biological and chemical materials.

Microorganisms were introduced into the anode compartment, the cathode remained abiogenic. As a biological load, a monoculture of a laboratory electronic strain of the genus Shewanella and a natural association of microorganisms based on anaerobic sludge from benthic MFE were preliminarily studied. During preliminary experiments in laboratory conditions, it was found out that a complex natural association of bacteria has a more stable bioelectrogenesis in a long period. As a result, this particular variant of biological load was chosen for the final experiment.

In the anode compartment of the MFE, images of sludge were introduced in two concentrations – higher (MFE No. 1) and 2 times lower (MFE No. 2). Meat-peptone agar was also introduced as a thickener and a source of nutrients. In the cathode compartment there was agar-agar without nutrients and a free volume of air (1/2 volume) for the formation of a gas medium. In a sealed module corresponding to the form factor of one cubesat unit, 2 microbial fuel cells of the design described above were placed. An electronic board was attached to the external surface of the hermomodule, including automatic voltmeters, memory cards, real-time clocks, etc. (Figure 8).

Figure 8. Biocapsule with control electronics

The microcircuit was connected to microbial fuel cells inside the hermetic module through a hermetic junction. In order to avoid galvanic effects, the anodes and cathodes in the MFE were made of carbon felt and connected to metal wires through carbon conductors.

During the experiment, the following data were obtained from the biological load: the dynamics of the electrical voltage generated by microbial fuel cells during the flight, before and after it (Figure 9).

Figure 9. Graph of measurement of bioelectrogenesis of microbial fuel cells

As can be seen, MFE No. 1, having a high concentration of microorganisms before the launch, created a greater voltage than MFE No. 2, with a smaller number of bacteria – about 374 and 317 mV, respectively. Immediately after the launch (17:27), a dynamic and synchronous decrease in the bioelectric activity of bacteria began. Lasted for 60 minutes for MFE No. 1 to a minimum level of 278 mV (18:28) and for 40 minutes for MTE No. 1 to a minimum level of 261 mV (18:09). Further, an increase in bioelectrogenic activity was recorded up to 18:48 in MFE No. 1 (330 mV) and up to 18:56 (386 mV) in MFE No. 2. Then there was a gradual decrease followed by an increase in voltage. Also presented data on changes in radiation levels and atmospheric pressure (Figures 10, 11).

Figure 10. Graph of measurement of dynamics and radiation in microbial fuel cells during flight

Figure 11. Graph of atmospheric pressure measurement during flight

The minimum values of electrogenesis coincide in time with the maximum radiation levels of 150-220 µRh/h. However, as the device decreased and the level of ionizing radiation dropped, bioelectrogenesis was quickly restored. In addition, the temperature rise factor probably also influenced.

In the course of the work, a CudeSat satellite was assembled and a satellite with a biological load was launched into the stratosphere. According to the results of the launch, such data as: temperature, coordinates of the spacecraft, radiation level, voltage generated by the biological load were obtained. Based on the results of the experiment, it can be concluded that all systems of the spacecraft are working properly. The microorganisms in the MFE proved to be resistant to the stress factors of stratospheric flight and restored their activity during the descent of the apparatus. In the further measurement of their activity, the absence of obvious critical violations was not visible. In the further development of the experiment, it is planned to launch a satellite with a biological load into low Earth orbit. The results obtained can serve as a basis for creating a bioengineered experimental platform for conducting biological experiments in minimal volumes.

References:

1. K.S. Popko, I.V. Pechersky Why does space need each of us? // Technopark of discoveries. No. 1 (0001) / KubSTU / 1.09.2020, pp. 28-33;
2. S. Kuzmitsky Nanosatellites created by Russian schoolchildren can be useful to geologists // Extractive Industry. No.2 (32) 2022 / PromoGroup Media Publishing House LLC, Krasnoyarsk / 2022, pp.124-129.
3. K. S. Popko The First space Odyssey of the Technopark (semi-selective history: IT-quantorians are on the trail) // Technopark of Discoveries. No.3 (0003) / KubSTU / 09/9/2021, pp. 10-15;
4. I.Y. Gluhenky Technopark "Kvant-Kuban-KubSTU" at the International Festival of scientific and technical creativity "From the screw!" // Technopark of discoveries. No.2 (0002) / KubSTU / 12.04.2021, p. 37;
5. Michael Paluszek, Eloisa de Castro, Derrek Hyland, The CubeSat Book. – 1st Edition. – Princeton University [Princeton Satellite Systems, Inc], 2010.