Space Travel Disadvantages: The commercial competition to take tourists into space is intensifying between Virgin Group founder Sir Richard Branson and former Amazon CEO Jeff Bezos. On Sunday 11 July, Branson flew 80 km to reach the edge of space in his Virgin Galactic VSS Unity spaceplane (Space Travel Virgin Galactic). Bezos’s autonomous Blue Origin rocket was launched into space on July 20, marking the anniversary of Apollo 11’s moon landing.
In this case, Alois Marais, Associate Professor in Physical Geography at UK’s UCL (University College London), said, these flights provided the opportunity for extremely wealthy tourists to reach outer space (Space Travel Blue Origin). On both trips, passengers enjoyed a brief ten-minute flight with zero gravity and a glimpse of Earth from space. Going a step further, Elon Musk’s SpaceX will conduct four to five days of orbital travel with its Crew Dragon capsule later in 2021.
What are the environmental consequences of the space tourism industry likely to be? Bezos claims that his Blue Origin rocket is better environmentally than Branson’s VSS Unity. The Blue Engine 3 (BE-3) used liquid hydrogen and liquid oxygen propellants. VSS Unity used a hybrid propellant consisting of a solid carbon-based fuel, hydroxyl-terminated polybutadiene (HTPB), and a liquid oxidant, nitrous oxide (laughing gas). The SpaceX Falcon series of reusable rockets will use liquid kerosene and liquid oxygen to propel Crew Dragon into orbit.
air pollutants are produced
The burning of these propellants provides the energy needed to launch rockets into space. Whereas greenhouse gases and air pollutants are also produced (Space Travel and Exploration). The burning of BE-3 propellant generates large amounts of water vapor, while the combustion of both the VSS Unity and Falcon fuel produces CO2, soot and some water vapor. The nitrogen-based oxidant used by VSS Unity also generates nitrogen oxides, compounds that contribute to air pollution near Earth.
change in nitrogen oxides
Roughly two-thirds of the propellant exhaust is released into the stratosphere (12 km–50 km) and the mesosphere (50 km–85 km), where it can persist for at least two to three years (Space Travel Advantages). . During launch and re-entry, the extremely high temperatures (when the return vehicle’s protective shield burns) also convert fixed nitrogen in the air into reactive nitrogen oxides.
negative impact on the environment
These gases and particles have many negative effects on the atmosphere. In the stratosphere, nitrogen oxides and chemicals formed by the breakdown of water vapor convert ozone into oxygen, thereby depleting the ozone layer, which protects life on Earth against harmful UV radiation (Space Tourism Pollution). Water vapor forms stratospheric clouds, which form a surface, causing this reaction to occur at a faster rate than under normal conditions.
space tourism and climate change
Due to the emission of CO2 and soot, heat stagnates in the atmosphere, which contributes to global warming. The atmosphere may also cool, as clouds made of water vapor emitted reflect sunlight back into space. A depleted ozone layer will also absorb less incoming sunlight and therefore warm the stratosphere less. Detailing the overall impact of rocket launches on the atmosphere would require detailed studies, to ascertain the impact of these complex processes and the presence of these pollutants in the upper atmosphere.
Virgin Galactic to send 400 passengers
It is equally important to understand how the space tourism industry will develop. Virgin Galactic estimates that it will arrange 400 space flights every year for the privileged who can afford it (Space Travel Disadvantages). Blue Origin and SpaceX have yet to announce their plans. But globally, rocket launches should not need to exceed the current number of 100 every year to avoid its harmful effects.
50 to 100 times more CO2 emissions
During launch, the rockets could emit four to ten times more nitrogen oxides than Drax, the UK’s largest thermal power plant, in the same period. CO2 emissions for four or so tourists in a space flight would be 50 to 100 times higher than the one to three tons per passenger on a long-haul flight (Space Travel Information). As international regulators need to keep up with this nascent industry and properly control its pollution, scientists need to better understand the impact these billionaire astronauts have on our planet’s atmosphere.