The space industry has a reputation for being a key player in the global fight against climate change, and understandably so.
Space missions provide us with a better understanding of our own planet, while satellite communication technologies enable humanity to optimise the use of natural resources by supporting fundamental services such as navigation, weather forecasting and power grid monitoring.
In the aviation industry, satellites contribute to reducing carbon emissions by greening flight paths.
Another industry to be heavily reliant on space technology is the Food industry, which uses satellites to monitor carbon emissions and develop eco-friendly feeding practices.
Over the years, the private sector has also benefited from NASA’s innovations in sustainable energy solutions, which include photovoltaics, fuel cells, solar power, geothermal energy, hydrogen-based fuels and power management distribution.
On top of that, the scientific community believes that future space missions to Mars will unlock the knowledge and understanding to accelerate sustainable technological development on Earth.
Having said that, the pace of growth undergone by the space industry may well hide a dark side.
In the last sixty years, humanity has launched into space about 11,000 satellites, 7,000 of which are still in orbit.
These numbers may not strike most people as excessive but ever since NATO declared space a commercial domain, more and more objects have been sent into space, with the number of traceable objects in orbit having nearly doubled in the last decade.
As space is coming to resemble any other commodity market on planet Earth, a question has finally come to the fore: how eco-friendly exactly is the space industry?
A long-lasting concern among industry experts has been space debris, 85% of which is composed of spacecraft fragments generated by explosions or collisions.
The problem is that the great majority of these objects are too small to be traceable and their number is estimated to have topped over 128 million units, according to recent statistical analysis.
The first obvious threat posed by space debris is that these objects physically endanger anything that passes through their orbital regions.
Besides directly threatening the use of space, space debris also poses a plethora of environmental problems.
Satellite re-entries from mega constellations are responsible for the accumulation of hazardous levels of alumina into the upper atmosphere, while larger constellations reflect sunlight back on Earth, emitting radio signals that affect the visibility of the night sky.
The environmental impact of light pollution is somewhat indirect but very much real: by interfering with astronomical observations, the skyglow effect is endangering the sustainable use of space.
According to the standards of the international astronomical community, the degradation of the orbital environment with space debris is responsible for a luminosity level that is already 10% above the natural threshold.
As a result, certain orbital regions have already reached the critical density of objects beyond which cascading debris collisions are self-sustaining, meaning that the number of space objects will continue to increase for thousands of years even without additional launches.
In this respect, planned mega-constellations in Low Earth Orbit are only bound to worsen the situation: looking at the current number of proposals for new launches, the end of this decade could see the number of in-orbit satellites reach the hundreds of thousands.
Comprising thousands of satellites with a life span of five to ten years, these constellations will produce vast amounts of debris that will further endanger the space environment and, paradoxically enough, their very own orbits.
It is clear therefore that the current pace of space expansion is unsustainable, but not all is lost.
It is somewhat reassuring to note that the international space community has been debating the space debris issue for several decades now.
Having said that, there is yet another major environmental issue that has received little attention so far, namely the carbon footprint of rocket launches.
Historically, space exploration has received little environmental attention because the industry has been relatively small.
As rocket launches used to be infrequent,their environmental impact looked negligible compared to other industries such as aviation.
The space industry has also benefited from being dominated by government agencies such as NASA, with discourses on national security often taking priority over environmental concerns.
However, the space industry has changed dramatically in the last few years.
The commercialisation of space has led not only to an increase in rocket launches (from 104 in 2020 to 133 in 2022) but to the emergence of whole new markets which are dominated by private companies, most significantly space tourism,
With the number of private launches expected to increase dramatically in the coming years, the World Meteorological Organisation has had no choice but to include rocket launches as a potential contributor to climate warming and ozone depletion.
A major environmental risk of space launches is the burning of solid rocket fuels.
As a result of launch exhaust, space rockets are responsible for the emission of harmful greenhouse gases, including hazardous particles such as alumina and black carbon.
By absorbing sunlight and trapping heat, these particles contribute dramatically to the warming of the stratosphere and, consequently, to climate change.
It is estimated that black carbon and alumina contribute respectively to 70% and 28% of the overall harmful emissions produced by rocket launches, which is particularly concerning because some rocket engines can produce 10,000 times more black carbon than most aeroplanes and jets.
Having said that, the amount of fuel burned by the space industry amounts to less than 1% the amount burned by aviation.
The production of GHG emissions produced by rockets is negligible compared to other industrial sectors but this is no reason to let the guard down.
Scientists have estimated that ten years of launches of hydrocarbon-based rockets at a rate of 1,000 per year could lead to a surface temperature rise of 1 °C.
At the same time, it is important to note that different rocket engines use different propellants, with their environmental effects varying depending on their chemical composition.
For example, liquid hydrogen engines produce water vapour exhausts that are generally considered ‘clean’. And yet, the production of hydrogen generates carbon emissions too.
Similarly, rockets propelled by hybrid engines are generally considered ‘green’ even though they produce significant amounts of soot that contribute to ozone depletion.
Due to the high temperatures reached during rocket launches, nitrogen is converted into nitrogen oxides that can significantly contribute to ozone depletion in the stratosphere.
Right now, the impact of rocket launches on ozone depletion is not of immediate concern but things may change soon as space tourism could expand beyond sustainable levels.
Taking as a reference point the scenario of 1,000 launches a year, scientists have predicted that space tourism could be responsible for ozone losses of up to 6% in the polar regions.
The problem is that the scientific community does not have enough data to tell exactly at what point satellite and rocket launches will have a measurable impact on climate change.
It is beyond doubt however that the stratosphere has been affected by the increasing number of satellite and rocket launches.
There is more than enough proof out there to push regulators to take into account ozone depletion into space legislation, such as the Clean Air Act and the National Environmental Policy Act in the US.
To prevent ozone depletion and global warming, regulators should consider establishing standards and requirements regarding rocket launches.
They should also take into account that studies considering only CO2 emissions may underestimate the impact of rocket launches given that harmful emissions are much more heavily impacted by black carbon and alumina particles.
About JP Aero
We supply a wide range of space industry fasteners. Whether standard, metric or custom design we are leading UK experts.
We are AS9120 REV A & ISO9001:2008 approved and SC21 compliant.
Over the years we have built up a broad depth of knowledge around all types of fasteners in commercial aviation, heavy industry, oil & gas exploration, defence and now the space industry.
Our long-standing commitment to quality and service means that we work with some of the biggest organisations within the space industry, and we are available to share that expertise in our field with you.
To find out more about procuring small satellite fasters contact our team today and we will be happy to help in any way we can.
Photo by Greg Rakozy