Introduction

Space activities require significant investments for their development. The budgets of national aerospace agencies and space corporations are comparable in volume to the annual gross domestic product of a number of European countries. Both the state and foreign investors invest large amounts of financial resources in the development of the industry. At the same time, the development of the national rocket and space industry faces a number of serious problems, among which the problem of ecology occupies a special place.

As the science of ecology has emerged relatively recently, its main postulates were formulated in the works of Haeckel (Haeckel, 2016), in which he studied the interaction of various biological objects. Later, environmental scientists began to pay more attention to the impact of human economic activity on the environment (Kemp, 2002). By the mid-twentieth century, it became clear that environmental problems are global in nature and require a special approach to solve them (Pelton, 2017).

Environmental problems arose in almost all types of economic activity, but nuclear power facilities and rocket and space technology had a particularly severe impact on the environment. The nuclear power plant accidents that occurred in 1985 in Chernobyl and in 2011 in Fukushima led to catastrophic environmental pollution and human casualties. If the level of environmental risks in the energy sector could still be affected by abandoning the use of nuclear power plants and switching to other methods of generating energy, then in space activities, the refusal or reduction of launches of rocket and space technology is impossible without serious socio-economic losses. The problem of finding solutions to the environmental safety of space activities is of particular relevance in connection with the intensification of the development of near-Earth space not only by industrially developed, but also by developing countries.

Currently, the problems of ecology are reduced in most cases to the protection of the biosphere from the impact of human economic activity, which does not fully correspond to the goals and objectives of this scientific direction. It is necessary to take into account not only the impact of enterprises on the environment, but also its impact on human activities. In connection with this understanding of the problem, it is necessary to study both the impact of the rocket and space industry on the environment, and the impact of space (radiation, meteorites, etc.) on human activities, living organisms and technical objects.

Materials and Methods

The purpose of the work is to assess the environmental risks of investments in space activities and develop approaches to reduce them. To achieve the goal, the following tasks are solved:

— study of possible environmental damage during space activities;

— identification of trends in the use of environmentally hazardous materials in space activities;

— study of the experience of reducing the risks of space activities;

— development of approaches to reducing the environmental risks of space activities.

The information base of the research includes statistics of space launches and accidents, publications in the open press, (Krebs, 2021) documents of national space agencies (NASA, ESA, Roscosmos) and international organizations (UNOOSA).

Quantitative research methods were based on statistical information, which served as the basis for constructing trends and trends in the use of environmentally hazardous materials and fuels through the mathematical modeling apparatus. The paper uses a probabilistic approach to assessing environmental risk for investments in space activities. It should be noted that the information base may, due to the specifics of space activities, contain closed information that can distort the result.

Technical methods for protecting the external environment from space technology launches are described in the works of J. T Shatrov., D. A. Baranov,V. Yu. Kudentsoc, D.V. Sitnikov, D. B. Lempert, V.I.Trushlyakov and other Russian scientists.

Qualitative research methods are based on a systematic approach. The external environment is considered as an ecological system consisting of interconnected objects of the Earth’s surface, flora, fauna and near-Earth outer space, which is exposed to human activity.

The paper uses the method of economic analysis, which examines the environmental risks and threats to the environment emanating from space activities, on the basis of which approaches are developed to assess and compensate for the damage caused to the environment. The author suggests that the strengthening of environmental control will stimulate work to improve the technical level of rocket and space technology and reduce the risks of negative impact on the environment.

Results

Impact of space activities on the natural environment

Space activity involves conducting scientific research for the purpose of studying and developing outer space, developing and operating rocket and space vehicles (RSV) for organizing communications, broadcasting and monitoring the earth’s surface, implementing defense programs, and more. The environmental impact of space activities can be divided into specific and non-specific factors. The group of specific factors includes the following:

— falling on the earth’s surface of stages and parts of launch vehicles;

— emissions of rocket fuel components and their combustion products;

— mechanical pollution of the environment during the launch of rockets;

— contamination of near-Earth space with spent fuel tanks, upper stages, RSV structural elements and failed spacecraft;

— destruction of the ozone layer and violation of the chemical composition of the atmosphere at the launch of the rocket (Alpatov, Krestnikov, 2018).

This impact may increase in the case of accidents with rocket and space technology, which tend to increase in the world (Figure 1).

Figure 1. Trends in the accident rate of RSV (Krebs. 2021; Online Index 2021)

Non-specific factors are associated with the functioning of enterprises of the rocket and space industry and space infrastructure facilities-spaceports, tracking stations, control centers, and others. In the vicinity of these enterprises, there may be an increased background of electromagnetic radiation, emissions of pollutants into the atmosphere, increased consumption of clean water, energy, and the like. During the launch of rockets, there is a strong acoustic impact on the environment, which can have a negative impact on the biosphere of the launch area.

A characteristic feature of space activities is the fact that threats to the environment are manifested at almost all stages of the life cycle of the creation of RSV from research and development to operation and disposal. Large volume of fuel combustion products is released into the atmosphere during tests of rocket engines on test benches, which causes environmental damage (Yang, 2010).

Over the 70-year history of space activity, engineers have managed to significantly reduce the negative impact of rocket and space technology on the environment. Dangerous areas were fairly accurately identified, evacuation and disposal of spent rocket parts were arranged (Shatrov, 2011), engines using less toxic fuels were developed. Currently, the negative impact of the launch of rocket and space technology on the environment is minimized and does not pose a great danger. Minor destruction of the ozone layer and mechanical and chemical pollution of the environment can be considered an inevitable side effect of space launches. A much more serious danger is posed by accidents with rocket and space technology, in which toxic materials and fuel are used.

One of the most efficient types of fuel, which is widely used in Russian launch vehicles «Proton», the French «Ariane», the Chinese «Long March», etc., is Monomethylhydrazine (MMH) and its derivatives are Unsymmetrical dimethylhydrazine (UDMH) (Shatrov, 2011). This type of rocket fuel is one of the most efficient from an energy point of view, but it causes great harm to the environment. UDMH и MMH are the most toxic fuel that affects humans, plants, and animals (Kubato, 2002).

Despite the fact that the use of rockets with environmentally harmful fuel in space activities has a certain tendency to decrease, their share remains quite high (Table 1).

Table 1

The use of launch vehicles using environmentally hazardous fuel (Krebs. 2021; Online Index 2021)

)* number of emergency launches

Over the past five years, there have been 7 accidents with rocket, in which there were toxic substances, which is 3.6% of all rocket launches using environmentally hazardous fuel.

It should be noted that kerosene used in rocket engines is not an environmentally friendly fuel, since its ingress to the surface of the earth or a reservoir poses a serious danger to flora and fauna. In the event of an accident at the stage of launching a spacecraft into orbit, there is a risk of falling parts of the rocket outside the designated areas, which can cause significant harm to the economy and human health.

The use of nuclear power reactors in spacecraft in high orbits poses another threat to the environment. In the event of an accident during the launch of the RSV or the launch of a spacecraft into orbit, fragments of nuclear reactors with fuel residues may fall to the Ground, which will lead to radioactive contamination of the atmosphere and the earth’s surface.

Impact of outer space on human activities and the biosphere

Outer space poses a serious threat to manned and automated flights. Cosmic radiation leads to the failure of electronic devices and equipment, and a collision with a micrometeorite or other objects can lead to partial or even complete destruction of the spacecraft.

The most vulnerable elements are solar panels, which cannot be protected by the spacecraft body. Attempts to protect the batteries with an additional layer of quartz glass and special alloying lead to a decrease in the battery’s efficiency and an increase in its weight (Slavyanov. 2018-a).

Cosmic radiation is a danger to computers, electronic devices and other spacecraft equipment, which can be damaged and fail when colliding with high-energy elementary particles.

The biological impact of cosmic rays on humans is dangerous by ionization of living tissues, which leads to the destruction of cellular structures.

The problem of so-called space debris has recently become particularly relevant for space activities. Space debris is commonly understood as all artificial objects and their fragments in space that are no longer functioning and cannot serve any useful purposes, but pose a danger to space flights and to the Earth in the event of their uncontrolled departure from orbit (Chen, 2011). If the orbits of space debris objects intersect with the spacecraft, there is a risk of their collision, as a result of which it is possible not only to destroy the existing spacecraft, but also to form a mass of debris that poses an even greater threat to space activities. So, as a result of the collision in 2009 of the decommissioned communication satellite «Cosmos-2251» and the American communication satellite Iridium, about 600 fragments were formed that pose a threat to other spacecraft.

The intensity of the launch of satellites is growing and almost at the same rate they fail, replenishing the volume of space debris by 4% per year. The collision of debris with each other leads to the formation of a whole cloud of particles, which is called the Kessler syndrome (Adilov, 2018), which gradually makes outer space unsuitable for manned and automatic spacecraft flights.

In the future, the problem of space debris may significantly worsen. A number of companies, such as OneWeb or SpaceX, have proposed launching huge fleets (constellations) of satellites into space, containing from several hundred to several thousand satellites. As you can imagine, the risk of collision increases significantly with the launch of so many satellites. These companies and their respective space agencies will have to prove that they have solutions to manage the space debris problem. They will have to provide convincing evidence that the satellites they launch have the technology to get rid of themselves, and there is also a solution to remove faulty satellites (Slavyanov, 2018-b).

Discussion

The problem of environmental safety is becoming increasingly important for all countries. In accordance with international treaties and current national legislation, the space agency must evacuate all spent rocket parts and other objects related to space activities in time, as well as compensate for damage caused to third parties. The problems of compensation seriously complicated interstate relations and escalated social tension in the regions. Thus, Roscosmos paid compensation to Kazakhstan in the amount of 2.4 million US dollars, although the injured party claimed $ 60 million (Interfax, 2007). As a rule, the Space Agency pays compensation for direct damage to third parties, but does not take into account indirect losses associated with the search operation, the creation of the necessary infrastructure for the evacuation of rocket parts. Liability insurance of enterprises engaged in the operation of space technology could significantly stabilize the situation.

The impact of specific factors on the environment can be reduced by switching to new, more environmentally friendly fuels, the use of which will open the way for multiple use of launch vehicles.

The problem of near-Earth space pollution has now become of paramount importance for space activities, and in June 2007, at a meeting of the UN Committee on the Peaceful Uses of Outer Space, the «Guidelines for the Prevention of Space Debris» were adopted, which include:

— limiting the formation of garbage during regular operations;

— minimization of the consequences of destruction during flight operations;

— reducing the chance of an accidental collision in orbit;

— avoiding deliberate destruction and other harmful actions;

— minimizing the possibility of destruction after the flight program is completed;

— limitation of the long-term existence of the spacecraft and the orbital stages of the LV in the areas of low-Earth and geosynchronous orbits after the completion of their flight program (Space Debris, 2010).

The proposal to register all objects in near-Earth orbit will make it possible to make legal claims to the country that caused the collision of space debris with a functioning spacecraft. However, it is difficult to determine the ownership of more than 300 thousand failed spacecraft, their elements, as well as meteorites that have fallen into the Earth’s orbit.

Currently, several options for removing space debris have been proposed, but solving this problem on the basis of modern technologies can take about a hundred years, and the costs of implementing projects can significantly slow down the development of other types of economic activities and social programs. At the present stage of the development of science and technology, the most effective systems are the detection and warning of the approach of spacecraft with space debris and other objects. Using its own engines, the spacecraft can slightly change its orbit and avoid a collision. The satellites that have served their term must have a fuel reserve that ensures a controlled departure from the working orbit.

To compensate for the damage caused by space activities to third parties, it makes sense to include mandatory liability insurance in the costs of space industry enterprises.

Thus, the improvement of rocket and space technology can lead to a reduction in the level of environmental pollution. National space agencies that are unable to solve technical problems on their own will have to compensate for the costs of neutralizing the consequences of accidents and pay increased contributions to the international Environmental Fund. The funds of the fund will be used for research and development in the field of ecology of space activities.

Conclusion

Taking into account the damage that may be caused to the natural environment, it is necessary to strengthen environmental control and the responsibility of national space agencies and RCP enterprises for violations of environmental legislation.

At the international level, it is necessary to create a special fund formed from the proceeds from countries involved in space activities. The amount of contributions should be proportional to the number of spacecraft in low-Earth orbit and the number of launch vehicles launched. The funds of the fund should be directed to international scientific research in the field of reducing near-space pollution.

For prompt compensation of damage to the environment and to third parties (affected households, businesses, individuals), the costs of liability insurance should be included in the expenses of the rocket and space industry enterprises. The amount of the insurance rate should depend on the level of technologies used and the number of emergency situations and incidents with space technology.

Investors should take environmental risks into account in their projects and invest in financing research and development in the field of creating new rocket engines using environmentally friendly fuels, as well as in the design of reusable rocket and space technology.

The author’s proposals will lead to an increase in the quality of rocket and space technology and reduce the risks of negative impact on the environment.

Acknowledgments

The reported study was funded by RFBR, project number 20-010-00350.