A space traffic jam is a more common concept than you might think!
Space is literally infinite, but we have created a cosmic traffic jam! After the land and oceans, space has become a graveyard for unwanted & unused artefacts.
What creates space junk?
Defunct satellites positioned in distant geostationary orbits are capable of circling the Earth for hundreds of years without triggering re-entry. They create junk by crowding up the orbit.
China, USA & India have also tested anti-satellite missiles. These tests, although rare, create thousands of additional pieces of space trash.
The increasing number of satellites in orbit increases the chances of collisions. Debris created from one collision hits other satellites which creates even more debris. This cascading effect is termed the Kessler syndrome.
According to NASA estimates, the Earth’s orbit currently has 500,000 pieces of space debris up to 10cm long, over 21,000 pieces of debris longer than 10cm, and more than 100 million pieces of space debris smaller than 1 cm.
The Next Space Race: Starlink & Mega constellations
Mega constellations are thousands of satellites that work as a group. All satellites in this group are placed slightly apart in the same orbit so that they can communicate with each other. This is useful to exponentially increase the speed of global communication. Elon Musk’s ambitious Starlink is one such constellation that aims to utilize 42,000 satellites2 to improve global internet connectivity. Governments of Europe & the UK also plan to launch rival mega constellations by 2022.
The number of satellites planned to be launched between 2019-2028 is more than 4 times that launched between 2009-2018. These satellites launched in unprecedented numbers will exacerbate the space debris crisis.
How does space debris affect everyday life?
Climate monitoring:
Climate monitoring satellites provide vital data to tackle climate change and can measure the concentration of greenhouse gases. These satellites also raise early warning signals for natural calamities. Weather satellites are placed either in Geostationary orbit at high altitudes or polar orbits which are low earth orbits. Satellites in polar orbits especially face high collision risk due to crowding from mega constellations which operate at similar altitudes.
Marine pollution:
Point Nemo is the most remote oceanic spot in the pacific ocean. It is 1,700 miles away from the chain of Easter Islands and serves as an oceanic dumping ground for more than 260 space crafts, half of which have crash-landed in the last few years3. This area is naturally lacking in wildlife. However, a barrage of space debris has contaminated the area with microplastics. The massive, 420-tonne International Space Station (ISS) will possibly be buried at Point Nemo, in 2024. While most space debris burns up on re-entry, the unburnt portions frequently crash into oceans. Ocean currents can carry these plastic particles, fuel tanks & carcinogenic rocket fuel over vast distances.
Ozone depletion:
Rockets emit soot, alumina particles, and chlorine-based compounds. All three types of emissions can promote ozone-destroying reactions, particularly when they’re injected directly into the stratosphere. Depleted ozone increases our susceptibility to skin cancer. Consequent UV ray exposure also affects plant growth and phytoplankton survival in marine ecosystems.
On re-entry, intense friction is caused due to travelling from a vacuum to an atmosphere full of gases. This burning of rockets releases noxious chemicals and GreenHouse Gases into the upper atmosphere. These gases, while negligible in amount, are generally more potent than CO2, and can deplete the ozone layer or retain more thermal radiation.
While ozone-depleting emissions are not at alarming levels today, the exponential increase in projected launches & their subsequent burn on re-entry paints a grim picture of the future.
Space exploration:
An increasing number of satellites have increased the brightness levels of the night sky. This light pollution affects our astronomical observation skills making it difficult to spot distant galaxies and perhaps life-supporting planets. This also affects long-distance migration for wildlife that rely on star positions to navigate.
Space junk can move at speeds of up to 18,000 miles per hour, almost seven times faster than a bullet which greatly increases its impact force. This poses an enhanced risk to manned missions which have to constantly be on the lookout for debris. The ISS frequently performs avoidance manoeuvres to steer clear of space trash.
NASA scientist, Donald J Kessler, prophesied that a chain of collisions may one day overwhelm the entire orbital space, making exploratory missions almost impossible.
Conclusion
Thus far, only the European Space Agency has set a launch date of 2025 for its first space clean-up programme; ClearSpace 1. This mission focuses on the removal of a single ‘Vespa’ Satellite.
In the absence of worldwide mitigation guidelines & general unwillingness to take action, it seems that space debris is a problem that is here to stay. Space programs provide us with amazing data & technology to positively change life on earth. Unfortunately, the legacy of space exploration by our species will be tainted by our perpetual inability to clean up after ourselves.
References
Jonathan O’Callaghan (2020, January 1). What is space junk and why is it a problem?
Natural History Museum
Yan, M. B. H. (2020, October 9). What Elon Musk’s 42,000 Starlink satellites could do for and to Earth. Business Insider.
English, T. (2020, April 16). Point Nemo: The Space Cemetery Where Thousands of NASA’s Past Projects Are Buried In. Interesting Engineering.
NASA. (2019, July 1). Space-Debris. https://www.nasa.gov/centers/hq/library/find/bibliographies/space_debris