Along with satellites and space stations, Earth is surrounded by tens of millions of pieces of floating space debris. Like any landfill, the trash is diverse, ranging from dead satellites to castaway rocket parts to flecks of paint. On average, over the past 40 years, one piece of space junk has fallen to Earth every day.
Scientists at NASA and private companies have devised several ways for clearing the sky. Although some methods are admittedly outlandish, says Nicholas Johnson, the chief scientist for orbital debris at NASA’s Johnson Space Center in Houston, Texas, a few are possible with today’s technology.
One early idea was to have robotic trash collectors shove large pieces of junk through the atmosphere so that they mostly burn up before hitting the ground. But the fuel costs for destroying a significant amount of debris with such craft has quashed this approach.
Tether demonstrations have so far yielded limited success or failed outright, but despite the setbacks, Johnson and others are optimistic that the tech could be ready in a few years. Here, a look at how the tethers might make the sky safe for space travel.
Step 2 Interactions between the Earth’s magnetic field and the charged ionosphere create and drive an electrical current in the metal tether.
Step 3 The current generates a Lorentz force—a phenomenon that affects charged particles moving in magnetic fields—that opposes the spacecraft’s orbital motion.
Step 4 Over the next weeks or months, the Lorentz force pushes the craft to lower altitudes, until it mostly burns up in Earth’s atmosphere.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.