In the 17th-century, when Italian astronomer Galileo Galilei looked out into the unknown vastness of space using his ingenious telescope, he saw the sun, the moon, planets, and stars. Had the polymath been looking through the telescope in the year 2021, he perhaps would have been disappointed to find not stars and other 'space oddities' so eulogized by mortals but bits of trash and plastic.
A 'drifting island of plastic'
While space enthusiasts sit in their plush homes congratulating themselves over human exploits on Mars and the strong message we are sending to the extraterrestrials who are silently but surely noting everything we do, space is filling up with innumerable pieces of junk. Six thousand tons of it.
Recent estimates by experts and scientific models have found 128 million pieces of space debris aimlessly bobbing around in outer space. These account for only the ones that are 1mm in size or smaller. There are also 34,000 larger pieces that measure over 10 cm.
In fact, some experts such as Ekaterini Kavvada, directorate general of Defence Industry and Space at the European Commission, have called the mass of space junk - specifically in Earth's lower orbit - a 'drifting island of plastic'.
Take that, Galileo.
What do we leave behind in space?
Harsh as it may sound, it is not surprising that humans have managed to pollute not just the known (Earth) but also the unknown (space). After all, cleaning up after ourselves was never a human hallmark.
Elon Musk, Richard Branson, and the likes measure the cost of space exploration in dollars but what indeed it should be weighed in metric tonnes. In fact, each attempt to understand the universe leaves it just a little bit more polluted.
Small bits of rockets that break off the body when they are launched in space, or scratches of chipped paint from bygone spacecraft, defunct satellites, leftover rocket boosters, remnants from past explosions of man-made objects, all contribute to space debris. A 2018 estimate by NASA put the number of defunct satellites in space at 500,000.
But don't underestimate these drifting vestiges of human curiosity (and vanity). Even a humble 1cm piece of speeding debris poses the threat to potentially destroy multi-million dollar satellites and cause high-velocity explosions in the sky.
While space debris has not caused any serious damage to Earth yet, let's not forget that time in 2015 when a rather renegade piece of a defunct Russian satellite traveling at the perilous speed of eight miles per second caused three ISS crew members to take emergency shelter in the Soyuz capsule.
Cut to September 2020 when ISS astronauts had to do an "avoidance maneuver" to get out of the way of a wanton piece of celestial junk. And this was just one of three such incidents that occurred in the last year itself. The ISS, which hovers some 240 km above Earth, orbits at the speed of 17,000 miles per hour. At that speed, even a tiny collision can cause unimaginable damage not only to equipment but also to the safety of crew members on board.
Cleaning up the universe
Mounting scientific evidence of the physical dangers of space pollution has increased the impetus on space waste-management and clean-up over the years. As far as private and state enterprises at the forefront of space exploration go, however, the reaction has been tepid at best.
To be fair to Musk, his aerospace company SpaceX did in 2018 launch a Falcon 9 rocket into space that carried along with supplies for the International Space Station an additional experimental "space sweeper" to clean up space debris. With the test run of the device, known as 'RemoveDEBRIS', scientists hoped that that space would get all cleaned up.
That was the company's 53rd launch into space. In 2020, SpaceX completed 100 launches with a set of Starlink satellites that were sent to space on October 24. One wonders how many 'RemoveDEBRIS' machines (created by U.K.’s University of Surrey Space Center, not SpaceX') it would take to clear up all the debris from all of Musk's satellites alone.
The more satellites are sent into space, the greater the risk of them smashing into each other. And with companies like SpaceX and OneWeb sending up entire constellations of satellites into the already crowded Lower Earth Orbit (LEO), experts fear setting off the Kessler syndrome - a chain reaction that leads to the creation of more space junk due to collisions between existing space junk.
Optimism or carelessness?
Some optimistic scientists hope that the problem of space debris will solve itself as objects in space tend to erode in time due to prolonged exposure to space. But this might be nothing more than wishful thinking.
Take, for instance, the case of a failed Envisat remote sensing satellite that is currently roaming outer space after the European Space Agency lost all contact with it in 2012. The satellite, which is the size of an Earthly bus, is expected to hang around for 150 years before naturally eroding.
With a view to addressing this problem, SpaceX’s president and chief operating officer Gwynne Shotwell proclaimed in an online discussion shared by Time magazine in October 2020 that the company's next-generation Starship programs could help in cleaning up space. But the noble aim remains secondary to the firm's primary goal which is to set up a conventional space route to ferry people and cargo to and from the moon.
In comparison, smaller private players are now coming up with alternatives that would do well to garner more attention. Rocket Lab, for instance, has come up with a system to launch rockets into space without creating space debris. By following a process of de-orbiting the launch stages, the company tries to ensure that no pieces of its rockets are left behind in space.