Space is getting pretty crowded. NASA estimates that there are over 21,000 pieces of space junk larger than 3.9 inches in orbit around Earth. This includes bits of spacecraft, pieces of launch vehicles and derelict satellites. The European Space Agency is exploring ways to capture and remove space junk and it's taking inspiration from the seas.
ESA researchers tested the use of nets (similar to fishing nets) as a possible way to catch dead satellites to remove them from orbit. A Falcon 20 aircraft replicated the weightless conditions of space as scientists used a compressed air ejector to shoot nets at a scale model of a satellite. The Falcon 20 (sometimes referred to as a "vomit comet") uses an elliptical flight path that gives occupants 20 gravity-free seconds for experiments.
Researchers discovered that thinner nets worked better than thicker ones. "The good news is they worked extremely well - so much so that the nets usually had to be cut away with a knife before we could shoot again," says ESA engineer Kjetil Wormnes.
The experiments are part of the ESA's e.Deorbit mission, which intends to test the removal of a large piece of space debris in 2021. Other methods being studied include the use of a harpoon, ion beam or robotic arm.
"The main advantage of the net option, whether for e.Deorbit or other debris removal missions in future, is that it can handle a wide range of target shapes and rotation rates," Wormnes says.
Perhaps in some sci-fi version of the future, space tourists will head into orbit to test their sporting prowess by fishing for space junk. It would be like chartering a boat in Florida, but with the vastness of space as a backdrop and wily broken-down satellites as the objects of the hunt.