Alastair Wayman, an advanced project systems engineer with Airbus, who helped to develop the high-tech system said it would prove to be “really effective at capturing space debris,” reports ABC News Australia.
“There’s kind of two challenges to space debris, one is capturing it and one is then actually bringing it down once you’ve captured it,” he said.
“And the harpoon is a really nice way to capture it. It really simplifies that because all we have to do is stand away from the target by a reasonable distance and fire at it. We don’t have to go up to it and actually get in contact with it at all.”
The Moby Dick of space debris
The space harpoon was developed to tackle one of the largest pieces of space debris orbiting the planet – The ESA’s old Envisat Earth observation platform. The huge, 8-ton satellite suddenly quit working in 2012 while in orbit.
The BBC is reporting that advanced project engineer Alastair Wayman, said, “If we can design a harpoon that can cope with Envisat, then it should be able to cope with all other types of spacecraft including the many rocket upper-stages that remain in orbit.”
Airbus tested the high-tech harpoon at the aerospace company’s facility in Stevenage, UK. The 0.9-meter-long (3 feet.) harpoon was fired using compressed air into a panel that mimics the kinds of material used to build satellite casings. The panels on a spacecraft typically have 3,0 centimeters (1.2 inches) thick, composite-honeycomb panels made mostly of aluminum.
“The harpoon goes through these panels like a hot knife through butter,” said Mr. Wayman. Immediately after the harpoon pierced the test material, a set of barbs opened up, keeping the harpoon from falling out.
In space, the harpoon will be attached to a “janitor” spacecraft by a tether, and after the harpoon is fired and becomes attached, the heap of space junk can be pulled into Earth’s atmosphere, where it will be disintegrated. This method could simplify the capture of space debris over other methods being developed, like nets and robotic arms.
Protection against the Kessler Syndrome
Since we began launching satellites into space during the 1950s, we have left behind an ever-growing amount of space debris, and every major power on the planet is at fault. According to NASA, the agency is monitoring approximately 20,000 objects as big or bigger than a baseball and 50,000 objects as big as a marble.
That number is in addition to the over 2,000 commercial and government satellites orbiting the earth at the present time. Additionally, there are an estimated 600,000 pieces of space junk ranging from 1 cm to 10 cm floating, and on average one satellite is destroyed each year.
But regardless of the size of the pieces of space debris, when they are traveling at 17,500 miles per hour, they can exert a powerful kinetic energy capable of significant damage upon impact. Knowing this can happen, and looking at the bigger picture, NASA scientist Donald J. Kessler proposed a scenario in 1978 called the Kessler syndrome (also called the Kessler effect, referring to a collisional cascading or ablation cascade).
Most manned and unmanned spacecraft are put into low-Earth orbit (LEO). This altitude range is low enough for residual air drag to keep the zone fairly clear. However, Kessler theorized that an increase in the number of objects in low-Earth orbit would lead to conditions where collisions between objects could cause a cascade where each collision generates space debris that increases the likelihood of further collisions.
Kessler surmised that one implication of this cascading effect is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges unfeasible for many generations. However, taking the Kessler Syndrome at face value, the scenarios predict an increase in the number of collisions per year, as opposed to a physically impassable barrier to space exploration that occurs in higher orbits, which are outside the parameters of the theory.
And yes, the Envisat satellite has been cited as a possible instrument in creating a Kessler syndrome. The massive spacecraft drifts at an altitude of 785 kilometers (488 miles), where the debris environment is the greatest—two cataloged objects can be expected to pass within about 200 meters of Envisat every year, and that number is expected to increase as time goes on.
It could easily become a major debris contributor from a collision during the next 150 years that it will remain in orbit said Kessler in an interview in 2012 Space Safety Magazine.
