What do a golden olive branch, art by Andy Warhol, and three golf balls have in common? They’ve all been left behind on the moon! And, while these items may be sentimental favorites, among this group are also three moon buggies and 54 unscrewed probes. All of this debris adds up to 190,000 kilograms of human-made material strewn about the moon. Space junk, however, isn’t exclusive to the lunar surface; the Earth’s orbit has 2,000 active satellites, 3,000 inactive satellites, 34,000 pieces of space junk larger than ten centimeters, and 128 million pieces larger than one millimeter.
But does space junk pose a danger to humans on Earth? Will the trash only pose a short-lived impact, such as the threat of falling objects, or will the detritus have a lasting effect, as space exploration programs are releasing tons of carbon into the atmosphere?
Space experts believe the chance of space junk falling to Earth and killing a human is pretty slim. This is because the majority of the Earth consists of oceans and there are huge swaths of uninhabited land. It is far more likely that the trash ends up in the ocean, without harming people. An example of this happened on May 9 with the descent of China’s Long March 5B rocket into the Indian Ocean. On a daily basis, copious amounts of space garbage circling the Earth descended into the atmosphere where much of an object’s components disintegrate due to the heat.
However, the long term impact of carbon emissions is alarming. Even when rockets and satellites incinerate upon re-entry, the process scatters alumina particles which do impact the environment. Alumina is a highly reactive oxide ceramic material widely used in fueling rocket boosters — the larger the space object, the bigger the fuel system, which ultimately creates more alumina particles. These particles get trapped in the stratosphere and deplete the ozone layer, allowing the effects of ultraviolet radiation to seep through.
As new companies like SpaceX emerge, there is no doubt that there will be more rocket launches, increased space junk, and further re-entries into Earth’s atmosphere. This has led scientists to rethink the manufacturing materials for rockets and spacecraft, with the goal of finding those that don’t generate alumina particles. Recently, a Japanese company made inroads by developing a wood-based technology with the aim of reducing harmful alumina particles. The United Nations has also gotten involved by requesting the removal of satellites from space within 25 years after final missions. Creative solutions as to how exactly this will be accomplished include dragging dead satellites via harpoon, net, or magnets, into the atmosphere where they will ultimately burn up.
Speaking on the Chinese rocket that landed in Indian Ocean on May 9, U. S. Defense Secretary Lloyd Austin said, “Spacefaring nations must minimize the risk to people and property on Earth… to meet responsible standards regarding their space debris.” In the 20th century, and more notably, the 21st century, ascent to space has become a more global endeavor — for example, the space agencies for the United States, Russia, Europe, Japan, and Canada work collectively on the International Space Station Program. Given the collaborative nature of space exploration, the solution to the problem of space junk must be a collaborative one. Because of the impact space activity has had on our Earth’s environment, world powers especially those who intend to to “colonize the cosmos” such as internet tycoons Elon Musk and Jeff Bezos must address the growing environmental implications of space trash.
