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Interstellar contamination | angle

In recent weeks, space tourism has become a reality for two of the world's richest men. Is it an expensive but harmless amusement, or another blow to the earth's battered atmosphere? We went out to check

By Yonatan Sher, Angle - Science and Environment News Agency

Richard Branson and the passengers who accompanied him on the first suborbital flight. PR photo, Virgin Galactic
Richard Branson and the passengers who accompanied him on the first suborbital flight. PR photo, Virgin Galactic

In recent weeks, it seems that the era of space tourism has officially opened, when two of the world's richest people: Jeff Bezos, founder of Amazon and the richest man in the world, and billionaire Richard Branson, flew into space for a short stay as tourists. Hundreds of the world's richest, among them Actor Tom Hanks and singer Lady Gaga, have already purchased tickets for the following departures.

It's hard to blame anyone who wants to take a short vacation from Earth, where floods, fires, and extreme weather events are becoming more and more frequent as the climate crisis worsens. But the way to get a few minutes where all the troubles seem smaller - a trip on the back of a fuel-burning monster called a rocket - may only make things worse. It is recommended to read before you call your travel agent.

A growing market

Space tourism did not start with Bezos and Branson. Already between 2009-2001 Hosted by the International Space Station Sheva private citizens who paid $25-20 million each for the flight and accommodation, and in 2019 NASA announced that it will allow tourists to come to the station again in the coming years.

The two richest space tourists of the last few weeks flew using aircraft manufactured by the companies they own: Blue Origin (owned by Bezos) and Virgin Galactic (owned by Branson). The experiences offered by Branson and Bezos include spending a few minutes in the first kilometers of space. Blue Origin takes the more "traditional" approach to reaching space, and uses a rocket that flies vertically with a passenger capsule attached to its head, which separates from it and then descends back to the ground using a parachute. Virgin Galactic, on the other hand, has developed a kind of space plane, which climbs to a height of 15 kilometers when attached to a larger plane, where it is released and activates a rocket that raises it another 70 kilometers, and finally returns to the ground and lands on a runway similar to a normal plane.

Blue Origin takes the more "traditional" approach to reaching space, and uses a rocket that flies vertically with a passenger capsule attached to its head, which separates from it and then descends back to the ground using a parachute. Bezos and his team, photo: Blue Origin

Against these initiatives, the space tourism program of SpaceX, entrepreneur Elon Musk's company, which launches satellites and astronauts into space, is more ambitious. The company plans to enter the market with a venturedear moon” (Dear Moon), in the framework of which 8 citizens will be flown in 2023 for a one-week journey to the moon and back. Yusuke Mazawa, a Japanese businessman, purchased all the tickets for the flight, and he plans to give them to various nationalities in order to promote world peace.

There is no smoke without fuel

The most significant difference between the different companies in regards to pollutant emissions lies in what happens under the "hood" - the fuel used by the aircraft. "When missiles take off into space, they need to take fuel with them, and also some kind of oxidizing agent, because at significant altitudes the concentration of oxygen in the air is not enough to allow the process of burning to occur," explains Dr. Victor Chernov from the Department of Mechanical Engineering at the Academic College of Engineering Ort Brauda in Karmiel. However, in different missiles different materials are used for this purpose. "In SpaceX's Falcon rocket Crocin is used - Refined petroleum, along with liquid oxygen, Blue Origin's rocket uses hydrogen and liquid oxygen, and Virgin Galactic's rocket uses solid rubber fuel and laughing gas as an oxidizer," explains Chernov.

In terms of polluting gas emissions, both the SpaceX and Virgin Galactic rockets emit a large amount of carbon dioxide into the atmosphere - but due to the fact that Blue Origin's rocket burns only hydrogen and oxygen, the only substance emitted from it is water vapor. If so, why aren't all missiles based on the technology of burning hydrogen? The reason for this is that beyond the environmental aspects, each type of fuel has its own advantages and disadvantages. "The problem with hydrogen is its storage: it is very volatile, flammable and explosive, in order to use it as a fuel it has to be cooled to minus 252 degrees Celsius, so that it becomes a liquid, and then you have to build a complicated system that maintains this temperature," says Chernov. "In addition, the temperature at which it burns is very high, so a system that knows how to handle heat is needed. Kerosene, on the other hand, is roughly the same fuel that is in airplanes, there is no need to cool it or build complicated systems, so it is very easy to work with, and solid fuel allows work with small missiles."

As polluting as 395 transatlantic flights

According to Virgin Galactic, the amount of carbon dioxide emitted by each of their flights into the atmosphere is equivalent to that emitted by Flight from London to New York and back, while the amount of emissions generated by the flight of SpaceX's Falcon 9 rocket, which, as mentioned, is intended to reach the moon and back, Equivalent to the one created following about 395 such transatlantic flights.

According to Virgin Galactic, the amount of carbon dioxide emitted following each of their flights into the atmosphere is equivalent to that emitted following a flight from London to New York and back. Branson and his team with the aircraft, photo: Virgin Galactic

However, even though it is a ridiculously high amount of emissions in relation to the relatively short operating time of the engines and the small number of passengers that these missiles serve, the fact that the number of launches that are carried out each year is very small makes, according to many researchers, the general amount of emissions created by the launch of the missiles negligible. According to NASA, in all of 2020 there were 114 rocket launches into orbit around the Earth - while on average, More than 100 thousand Planes take off every day. Therefore, while the airline industry Responsible for about 2.5 percent of carbon emissions, the space industry is only responsible for about 6 million percent.

Straight into the atmosphere

At the same time, some recognize the location to which the polluting emissions are directed - straight to the upper layers of the atmosphere, as a possible danger. "The layer of the atmosphere that is 50-12 kilometers above the ground, called the stratosphere, is the one that includes the ozone layer that is responsible for absorbing the ultraviolet radiation that is dangerous to life on Earth," explains Prof. Yoav Yair, Dean of the School of Sustainability at the Interdisciplinary Center Herzliya. "Flying at these altitudes introduces into this layer substances that should not be there, such as greenhouse gases that absorb infrared radiation (infra-red, i.e. heat, Y.S.), and this has a climatic effect. In addition, this layer is very stable, so any material that enters it remains there for years." Another layer through which rockets fly before they reach space is the mesosphere - a very thin layer with complex and completely unknown chemistry.

There is scientific evidence for this Emissions that reach the upper and more sensitive layers of the atmosphere can dilute the critical ozone layer for all living things on land. In addition, the particles that are emitted into the stratosphere and mesosphere may accumulate for years and block part of the sun's radiation from reaching the ground (by absorbing it or returning it to space) - and thus they may in fact cool the surface of the earth in an uncontrolled manner and constitute a type of climate engineering - A theoretical and experimental practice (on a very limited scale) that opinions regarding the effectiveness of its future use are divided in the scientific community. But as mentioned, it seems that at the current rate of launches, the effect on the flux of solar radiation that penetrates through the atmosphere is not significant.

"Currently, space tourism does not affect the atmosphere", reassures Yair. "However, if we talk about the next century and a significant increase in the scope of the industry's activity to the point of several launches a day, it will be a different story"

As for the future of the space tourism industry, Chernov is optimistic. "Most people who grow up today and become engineers understand the importance of taking care of the environment", he concludes. "I believe that as the industry develops and its impact becomes more significant, there will also be more efforts to reduce the pollution it produces."

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