October is Space Month. At Duke University, space research is more than just science - it's a bold journey across disciplines. This is the fifth in a series of stories featuring innovators, dreamers, and students shaping the future exploration and regulatino of the cosmos.
In the early days of space exploration, satellites were rare. Each launch was a feat of engineering and ambition, sending machines far above the Earth into orbits where they could drift undisturbed.
These high-altitude paths offered vast expanses of space, minimizing the risk of collision. The sky was a lot quieter.
These days, however, "aim higher" is no longer the mantra. Low Earth Orbit (LEO), once sparsely populated, has become the new frontier for newly launched satellites, said Giovanni Zanalda , professor of the practice in the Social Science Research Institute and in the Department of Economics, and director of the Space Diplomacy Lab (SDL) in the Sanford School of Public Policy.
The lab focuses on creating diplomatic strategies to deal with space security challenges and international space disputes, which are likely to increase as more private and governmental organizations take to the skies.
The reason to choose LEO is more than just economic. Satellites in lower orbits communicate faster with Earth, reducing delays in transmission to mere milliseconds. This makes them ideal for improving internet services, Earth observation and communications. Companies are racing to deploy these satellites and blanket the planet in connectivity. But with this rush comes a problem: Space is no longer empty.
Unlike the vast highways of high-altitude orbits, LEO is a relatively narrow belt that is now getting congested.
Cluttered Orbits, Congestion and Fragments
"Imagine two interstate highways intersecting at odd angles, with cars speeding at thousands of miles per hour and no traffic lights. That's what our orbital environment has become," said Zanalda.
The total number of satellites in Earth's orbit is close to 16,000 , including around 13,000 active and 3,000 inactive or decommissioned ones, according to various sources. The oldest satellite still orbiting Earth is the USA's VANGUARD 1, which was launched on March 17, 1958. Although communication was lost in 1964, scientists suggest it could be in orbit until around the year 2198.
"Imagine two interstate highways intersecting at odd angles, with cars speeding at thousands of miles per hour and no traffic lights. That's what our orbital environment has become."
Giovanni Zanalda
Satellites must maintain high speeds to stay in orbit. There's no stopping, no pulling over. If they slow down, they fall back to Earth. If they collide, they shatter. And when they shatter, they don't disappear.
Fragments from collisions, discarded rocket stages, and dead satellites remain in orbit. Some burn up upon reentry, but many don't. They become space debris - tiny shards of metal and plastic, each traveling at speeds fast enough to puncture spacecraft. These fragments don't just pose a threat to future missions; they multiply. One collision can create thousands of new pieces, each capable of causing further damage. This cascading effect is known as Kessler Syndrome. The term was coined by NASA space debris expert Don Kessler, who observed that, once past a certain critical mass, the total amount of space debris will keep on increasing through collisions, giving rise to more debris and leading to more collisions, in a chain reaction
Astronomers have long warned of this possibility. The night sky, once a canvas for discovery, is now streaked with artificial light from debris and active satellites, notes Arun Kannawadi , an observational cosmologist and assistant research professor in the physics department.
Satellites reflect sunlight long after dusk, creating light pollution that interferes with telescopes and observatories. Ironically, the same companies that dream of interplanetary travel are cluttering the same launch paths they'll need to escape Earth's atmosphere.
And it's not just science that suffers. Wildlife, especially nocturnal species, are affected by the artificial glow. Human circadian rhythms are disrupted, which in turn affects our health. The consequences ripple across ecosystems and societies," said Kannawadi."
"If satellites are disrupting circadian rhythms, how many days or years of life are we losing? What does it mean to permanently lose the night sky, a source of wonder and identity for humanity?"
There are ecological consequences, too. Migratory birds rely on the stars to navigate. Disrupting their patterns affects ecosystems, which in turn affects agriculture and food security. These indirect effects are harder to quantify, but no less real.
"This is a very complex problem in the sense that it's going to need a lot of people with different expertise to come together to be able to do something about it," Kannawadi said.
Need for Regulations
The 1967 Outer Space Treaty laid the groundwork for international space law, including ownership, responsibility and liability, but it didn't anticipate the debris crisis. The world has been trying to catch up, but consensus is elusive; there are still no binding international agreements or an international agency for removing space debris and governing space traffic.
The Orbits Act , a promising piece of U.S. legislation aimed at addressing space debris, has stalled in Congress. Zanalda co-authored an op-ed on the bill, summarizing the problem and linking to key datasets.
Problems surrounding space debris and norms of behavior in orbit are not things that should be pushed off to deal with in the future. "They require such a long-term horizon that, sometimes, from a political point of view, it is not a priority," Zanalda said .
Space debris is a global problem; there's only one sky. No country can claim a clean slice while polluting the rest. The consequences are shared, and so must be the solutions, say the experts.
