Wherever humans go, machines precede us. Since the 1950s, humanity has sent satellites deeper into space than it ever imagined possible — including the moon, Mars, the outer planets, and even interstellar space.
However, in low-Earth orbit, the future of space looks dire — crowded with more than 7,500 metric tons of space junk from a half-century of science, military, and (mostly) commercial satellites. Soon, space will become a $2.7-trillion industry, as mega-constellations like SpaceX's Starlink fill the night sky with commercial traffic.
If we're going to keep sending mass into low-Earth orbit, we need to find a way to de-orbit the junk, while also ensuring that new additions to the metal cloud are short-lived.
Future of space might depend on self-destructing satellites
Growing more rapidly than any other satellite program is SpaceX's Starlink constellation of internet satellites — which has launched at least 60 satellites this year, and nearly 1,100 total — with plans to have up to 42,000 in orbit. While these are designed to naturally de-orbit when their engines die, in the meantime they add substantial activity to an already-busy shell of metal.
Additionally, Starlink satellites can disrupt astronomers' observations of space from Earth. SpaceX is developing "dimmed" models of its Starlink (called DarSats), designed to be less reflective than earlier models — and thus appear less visible to ground-based observers, a recent study suggests the darkened models won't lower the "noise" of light pollution.
Self-destructing satellites can help scale-down space junk
On Thursday, a Dutch internet-of-things (IoT) company named Hiber announced that its recently launched second-gen CubeSat — called Hiber Four — features on-board propulsion, which will help engineers guide it away from potential collisions. But crucially, the low-mass satellite will also de-orbit itself, careening back into the atmosphere to burn up upon exhausting its lifespan.
Japan's space agency (JAXA) also plans to test a self-destructing satellite — with aims to adapt its proliferating low-Earth orbit (LEO) fleet for commercial scales, without adding to the shell of space junk.
Japan's micro-satellite tech could offer commercial alternative
The tech was developed via the Japanese satellite-killer startup, called ALE Co., and aims to arm satellites with a carbon nanotube cathode along with an electrodynamic tether. Once a satellite completes its mission, it will spool out a tether, creating a current flow between the satellite and the cathode.
Reacting with Earth's magnetic field, combined with Earth's gravity and the minute friction present in the very high atmosphere, will pull the satellite down into an inferno of mechanical death — leaving empty space in its orbital wake.
The new technology will see testing on a micro-satellite in 2021 — and if it works, JAXA hopes to sell it to commercial satellite builders.
"By the development of the device with this joint onboard demonstration, it will become possible to reduce the number of satellites remaining in a low-Earth orbit, which is expected to increase rapidly in the future, and to thereby prevent the generation of large quantities of hazardous debris caused by collisions with other space debris," said the agency, according to a report from The Register.
What we do on Earth reflects what we'll do on Mars
However, how will we know where to look to clean up space junk, and how can we tell if our efforts are working? A company called Northstar "monitors space, from space, via a constellation of satellites with dedicated optical sensors," according to the company's website.
Northstar does this with an expansive data-driven 3D catalog of the surrounding space environment — using advanced SSA analytics to provide crucial information so other commercial and public parties may safely navigate LEO.
Satellites and uncrewed spacecraft have taken human exploration far. With the ever-expanding network of IoT technology and societal reliance on geostationary satellites — added to rapidly-expanding commercial interests, we should make sure we learn how to control the junk factor on Earth, before building a presence on the moon and Mars.