Space Debris and Light Pollution Threaten Astronomical Research and Earth’s Climate
Once upon a time, gazing at the night sky was an escape from manmade messiness on Earth. Not anymore. Nearly 70 years after the launch of Sputnik, there are so many machines flying through space, astronomers worry their light pollution will soon make it impossible to study other galaxies with terrestrial telescopes.
The Problem of Space Junk
Then there is the space junk — nearly 30,000 objects bigger than a softball hurtling a few hundred miles above Earth, 10 times faster than a bullet. This space debris poses a significant threat to both astronomical research and Earth’s climate. According to a study conducted by NOAA’s Chemical Sciences Laboratory, 10% of the particles in the upper atmosphere now contain bits of metal from rockets or satellites falling out of orbit and burning up. As humanity becomes increasingly dependent on information beamed down from above, the report predicts manmade debris will make up 50% of stratospheric aerosols in the coming decades, matching the amount created naturally by the galaxy.
The Commercial Shift and its Consequences
The commercial shift from solid rocket boosters on NASA’s Space Shuttles to the kerosene that fuels SpaceX rockets has added tons of new fossil fuel emissions with every launch. Additionally, aging satellites create clouds of debris as they deorbit. “We’re talking about constellations of thousands of satellites that each weigh a ton or so, and when they come down they’re acting like meteoroids,” says Troy Thornberry, a research physicist at NOAA’s Chemical Sciences Laboratory.
The Growing Number of Satellites
According to the tracking site Orbiting Now, there are currently more than 8,300 satellites overhead, and predictions of how many will soon join them vary wildly. More than 300 commercial and government entities have announced plans to launch a staggering 478,000 satellites by 2030, but that number is likely inflated by hype. The U.S. Government Accountability Office predicted 58,000 satellites will launch in the next six years. Other analysts recently estimated the number likely to make it to orbit is closer to 20,000.
The Threat of Kessler Syndrome
The issue of space debris has been a concern since 1979 when NASA scientist Donald Kessler published a paper titled “Collision Frequency of Artificial Satellites: The Creation of a Debris Belt.” This paper introduced the concept of “Kessler Syndrome,” which refers to the worry that too much space traffic will eventually create a vicious cycle of more debris leading to even more collisions until launches become impossible. In low-earth orbit, objects can collide at around 23,000 miles an hour, enough for even the tiniest debris to crack the windows on the International Space Station. It is estimated that there are currently 100 million pieces of man-made debris the size of a pencil tip whizzing in orbit — a major risk of doing business in space.
The Emergence of Orbital Debris Removal
In response to the growing concern over space debris, companies like Astroscale are emerging in the field of orbital debris removal. Astroscale, a Japanese company with a U.S. branch, aims to develop technologies for removing space junk and ensuring space sustainability. Ron Lopez, president of Astroscale’s U.S. branch, compares their role to that of the companies that made pickaxes and shovels during the Gold Rush. While they are still far from achieving their goals of flying garbage trucks and orbiting recycling centers, Astroscale has made significant progress. In 2022, they used a satellite with a strong magnet to catch a moving target launched in the same three-year mission, demonstrating technologies required for docking and rendezvous with other satellites.
A Closer Look at Space Junk
Astroscale’s second mission, launched from New Zealand by aerospace company Rocket Lab on February 18, aims to take a closer look at space junk. The satellite, named ADRAS-J, will observe the motions of a rocket stage that was left in low-Earth orbit in 2009. Astroscale’s mission will use cameras and sensors to study the rocket debris and figure out how to remove it from orbit.
The Future of Space Sustainability
The issue of space debris and light pollution is gaining significant attention in the space industry. “Ten years ago, people thought that our founder was crazy for even talking about space debris,” says Ron Lopez. “Now you can’t go to a space conference without a panel or a series of talks on space sustainability and the debris issue.” With the growing number of satellites and the potential consequences for both astronomical research and Earth’s climate, it is crucial to address the problem of space debris and work towards a sustainable future in space.