Space Effect Explained: Spaceflight & Space exploration impact on the environment13th Dec 2021
Humanity has entered the 21st century with a serious problem — climate change, provoked by increased carbon emissions caused by industrial activities and transport, including space effect from satellite launches and tourism flights. The main sources of carbon dioxide — industrial production, transport, megacities — produce such an amount that it becomes thermal insulation for the planet. Greenhouse gases accumulate in the gaseous mantle of Earth and prevent the solar thermal energy from returning back into space. The surface of the planet heats up, the ice begins to melt, the level of the World Ocean is changing. This leads to natural disasters, which may soon become an insoluble problem.
The need for carbon neutrality measures is becoming increasingly evident. Indeed, big businesses are gradually rebuilding their manufactures, and developed countries are tightening their policies on environmental pollution. The transition to electric cars and green energy is not far off, but this process is slow, and not everyone wants to participate or can quickly adapt. Let’s agree, it is difficult to imagine third-world countries moving to Euro 6 or ICAO aviation standards. The growing number of space launches is equally alarming. Are rockets bad for the environment? After all, CO2 emissions from rocket launch are tens, if not hundreds of times, higher than those from other aircraft.
So, are rockets bad for the environment? Orbital Today tried to assess rocket launch environmental impact to find out if space flights are truly so harmful and if we should be concerned about the increase in their number and the environmental impacts of space exploration.
Space flights growth increases harmful emissions
This is the main space impacts horror story for today, which, however, is not unjustified. 2021 marked the beginning of the space tourism era. Private space leaders such as Blue Origin and Virgin Galactic successfully completed their first suborbital flights and will soon begin selling tickets to the public. Space X goes even further and sends the first Inspiration mission with four civilian astronauts into orbit. In addition, the number of satellite launches is growing.
Scientists sound the alarm as to the environmental impact of space exploration because one average spaceflight emits 60 times more carbon per passenger than a 10-hour Boeing 747 flight.
However the main problem is space pollution effects. Rockets pollute the high layers of the atmosphere, inaccessible for planes — the stratosphere, which begins at an altitude of 10 kilometres, and the mesosphere (from 50 km). Until now, rocket launch environmental impact on the atmosphere has been negligible. But that’s simply because there weren’t many launches.
The forecast shows that the number of suborbital space flights will grow to 400 per year by 2030. The same goes for satellite launches. Now, an average of 120-150 launches are made each year, but in the next two years, this figure may double. SpaceX’s Falcon alone carries out up to 50 launches per year, and providers such as Rocket Lab or Virgin Orbit plan to do 20-25 launches a year. And this is not the limit when it comes to the environmental impact of space exploration. By 2023, the payload launch market should be replenished with at least five launchers from Europe and two more from the USA. This cumulatively amounts to hundreds of thousands of tons of carbon emissions into the atmosphere, increasing the environmental impacts of space exploration.
What about rocket fuel space effect?
Until now, the main measurements of the rocket launch environmental impact on chemical processes in the atmosphere dated back to the space shuttle era. Scientists have proven that solid-propellant rockets have an extremely negative effect on the ozone layer. The influence of hybrid rocket engines is somewhat less, and modern liquid propellants, such as Blue Origin’s BE-4, do not emit any CO2 on burnout. However, they are associated with other space pollution effects. Liquid fuels, such as the widespread RP1, are a mixture of liquid oxygen and liquid hydrogen. During the production of the latter, a large amount of CO2 is emitted. Compressing and liquefying oxygen for fuel also results in carbon pollution unless done with renewable energy sources.
The water vapor generated by the exhaust of liquid-fueled rockets is by no means harmless because the longer it stays in the atmosphere, the more it heats up the planet. However, scientists are most alarmed about other environmental impacts of space exploration, particularly small particles of soot and aluminum oxide being released into the air when rocket fuel is burned.
Research has shown that 1,000 private suborbital flights a year can raise temperatures over the poles by 1 degree Celsius and reduce polar sea ice levels by 1 degree, adding to the harmful environmental impact of space exploration.
Below you can see what heavy launch vehicles emit into the atmosphere in one launch, along with the amount of those space impacts.
Yet rockets currently account for only 0.1% of the world’s CO2 emissions. Aviation accounts for about 3%, cars — for 50% of the entire transport industry, and the average cruise ship emits so much nitric oxide and sulfur oxide that standing on its deck is the same as standing in the center of one of the most polluted cities in the world.
However, this does not mean that one should turn a blind eye to the rapidly growing number of rocket launches. In addition to air pollution, they cause another equally dangerous space impacts problem.
The accumulation of debris in orbits is the primary space problem today. At the end of 2020, the number of active satellites orbiting the Earth exceeded 3,000. The number of spent spacecraft is approximately the same. The average life of a satellite is 3-5 years, after which it turns into useless junk drifting in orbit — and the number of space junk keeps growing. In addition, some spacecraft fall apart into multiple debris, the number of which has already exceeded 20 thousand, adding to the pressing problem of space pollution effects.
As a result, this can lead to the so-called Kessler syndrome (domino effect), when the collision of two sufficiently large objects will create a large number of new debris, each of which can potentially collide with other space junk and cause a “chain reaction,” causing even more new debris.
With a large number of collisions or an explosion (for example, in a collision between an old satellite and a space station), the amount of avalanche-like new debris will make the near-earth space completely unsuitable for flight. This means that humanity will not only lose access to Earth Observation and communication satellites but will also have to abandon Moon and Mars exploration.
Many space agencies and companies are already addressing this problem. In particular, spacecraft to remove space debris from orbits (for example, Skyrora Space Tug) is in development. Space tugs will transfer space junk to disposal orbits above geostationary satellites or ensure their smooth descend to the ground, where the debris will burn up upon entering the atmosphere. However, there is a risk that until the work in this direction becomes effective, the number of satellites in orbits will increase by another 10-20%, which will only complicate the issue.
So, are rockets bad for the environment? Should we sound the alarm over the growing number of spaceflights? Probably not just yet. However, we should take appropriate measures even now — develop new low-toxic fuels, clean up orbits from trash accumulating there for decades, and build new spaceports minimizing the harmful effects of launches on local residents and nature.
After all, the space industry is not only billions of dollars in profit but also humanity’s chance at a comfortable future. However we need to tread this path carefully, considering every step for every mistake can cause another adverse space effect.