Collecting Junk In Space

"Collision risks from on-or-hit debris is of significant importance, especially given the growth potential for smaller spacecraft."
"Given the increased interest in the exploitation and exploration of space there is an opportunity for Canadians to take a leadership role in keeping space safe for all, and for Canadian industry to reap the economic benefits that will come with finding effective and cost-efficient solutions to the problem of spaced debris."
Dan Le Bouthillier, spokesman, Department of National Defence (DND)

"While 'space debris' technically includes asteroids, comets and meteoroids, this challenge refers specifically to orbit debris, space junk, space waste, space trash, space litter or space garbage, as well as fragments from their disintegration and collisions. Space surveillance networks regularly track about 22,300 debris objects in earth orbits, totaling more than 8,400 tonnes, which includes 1,950 operational satellites. As of January 2019, the total number of debris objects that are estimated by statistical models to be in earth orbits are 34,000 (greater than 10 cm); 900,000 objects (1 cm to 10 cm); and 128 million objects (1 mm to 1 cm)."
"When in Earth orbits, space debris pose a risk of collision with space vehicles, humans, and even with other debris. The hazards posed by debris collisions include erosion to hulls, solar panels and optics; fragmentation leading to rapid increases in the total population of space debris; total loss of a vehicle and/or an asset; and major injury and/or loss of human life. Space debris will grow as the number of human-made objects in Earth orbits increase over time."
"There are no operational debris removal capabilities in use, globally, and existing prototypes lack important capabilities and have proven ineffective. For instance, there is a need to capture and deorbit multiple pieces of debris per clean-up effort or the capability becomes extremely expensive; as well, capabilities are needed to track and capture space debris smaller than 10cm or larger than the capturing vehicle (e.g., rocket bodies)."

From invitation to tender for tracking "space junk" by DND 

The Canadian Defence Department is calling on scientists to use their technical expertise and creative intelligence to arrive at a possible system whereby space junk orbiting Earth can be collected as waste, and disposed of, ridding the inner atmosphere of the presence and the potential of impact accidents with satellites and other types of operational spacecraft. Recommendations and plans for tackling space junk and "de-orbiting" the debris have been invited and DND is awaiting associated proposals by mid-August.

"Debris objects" in orbit is estimated to total roughly 129 million, including 34,000 objects larger than 10 cm in size; 900,000 of one cm to 10 cm; and 128 million objects one mm to one cm, according to DND calculations. Decades of space travel and operations are responsible for having created the debris. Like Mount Everest and the countless expeditions that have been launched to summit the world's highest peak, the issue of garbage strewn everywhere on the mountain is beyond vexing.

The total number of "debris objects" in orbit is currently estimated to be around 129 million, ncluding 34,000 objects greater than 10 centimetres in size.   Getty Images illustration

In 2007, China conducted a military test for a missile to destroy one of China's satellites. The result of this military-launched experiment was that the space craft was successfully intercepted by the warhead which obliterated it and in the process an estimated 300,000 pieces of debris resulted. The space debris currently in orbit has accumulated as long as nations have launched exploratory satellites, and with a reawakened interest in space travel a vastly increased amount of "space junk" is set to arise.

Military experiments similar to China's have also been undertaken by the United States, Russia and India. Innovative, new methods to track and retrieve pieces of debris of any size, to begin to clear up the orbiting junk is imperative to safety of future space travellers and the security of satellites in orbit sending back vital signals to Earth, transmitting communications and vital data all over the world. At the present time, space surveillance networks track about 22,300 objects in Earth orbit, including 1,950 operating satellites.

The Canadian Forces' own satellite, Sapphire, used to track space objects in high Earth orbit was launched in 2013 to provide information to the Canadian Armed Forces relating to locations of foreign satellites, along with the directional presence of orbiting debris whose potential hazard to satellites and other spacecraft is worrisome.

Overview of the Sapphire system key elements (image credit: MDA)