Humans leave trails of trash wherever we go, and that bad habit extends to outer space. In particular, low Earth orbit has become so cluttered with debris that some space scientists fear a triggering of the Kessler syndrome, in which one errant collision leads to a cascade effect of subsequent crashes producing even more debris, a scenario that was dramatized in dizzying detail in the space thriller Gravity. Such a disaster could stall spaceflight attempts for decades or more.
The European Space Agency (ESA) is a world leader in the effort to clean up the space junk that has accumulated around the planet since 1957, when Sputnik became the first artificial object to reach low Earth orbit.
On Tuesday, ESA kicked off its seventh European Conference on Space Debris, held in Darmstadt, Germany, by releasing an intense 12-minute-long documentary that illustrates the threats posed by the estimated 700,000 centimeter-scale objects and 170 million millimeter-scale objects that litter the orbital environment near Earth.
"Space debris—a journey to Earth." Video: ESA/ID&Sense/ONiRiXEL
We tend to imagine space as a pristine and boundless frontier, but the animations in this video show just how crowded it has become, especially in the geostationary and low Earth orbits.
The higher the density of space debris, the higher the risk of collisions that could spark a cataclysmic cascade event. This is especially problematic with the advent of small, cheap satellites, such as the popular CubeSat platform, which may significantly contribute to space debris over the coming years.
The ESA warns that this is not only a problem for Earth's surroundings. Mars orbit is already home to several dead spacecraft, including NASA's Mars Global Surveyor, which arrived at Mars in 1997, and the Russian Phobos 2 orbiter, which arrived in 1989. For the moment, these robotic corpses aren't numerous enough to pose a major hazard, but as humans continue to build a presence on Mars, space debris is likely to become a risk there as well.
Space debris is an intimidating issue, but a quick browse through the ESA conference program shows that some of the world's top scientists are dedicated to fixing it. Dozens of strategies for preventing collisions and safely disposing of space junk will be discussed at the meeting, so follow the livestream.