We now have a satellite catcher to clean up space junk,We are closer than ever to witnessing the “Kessler syndrome,” a scenario proposed in 1978 by NASA scientist Donald Kessler in which the high density of objets and debris in low Earth orbit creates a cascade of collisions that renders space travel and satellite use impossible for decades. However, how close we really are is a matter of debate.
The United States Space Surveillance Network, operated by the Air Force, estimates there are more than 500,000 pieces of debris larger than 1 centimeter orbiting Earth today, including 21,000 pieces larger than 10 cm that are actively tracked. And that’s ignoring the millions of smaller bits that are also up there. The average speed at which space junk would collide with a satellite is approximately 10 kilometers per second, meaning collisions with debris as small as 0.2 millimeters can still do damage.
In March, engineers will gather at the 2015 IEEE Aerospace Conference, in Big Sky, Mont., to figure out what the real dangers are and what, if anything, we can do about them. The organizers of the conference’s session on space debris, Kaushik Iyer and Doug Mehoke from Johns Hopkins Applied Physics Laboratory, are themselves cautious about ringing the alarm bells.
“Space is a very, very big place,” says Iyer. “When you do the probability analysis of when spacecraft will collide with debris and how much damage will occur, generally you see that it’s an extremely unlikely event.”
To deal with space junk today, space agencies use ground-based radar to track debris larger than 10 cm and supply that information to the owners and operators of satellites that may be in the way. Those people can choose whether or not to carry out collision-avoidance maneuvers—if they have that capability. Jer Chyi Liou, NASA’s chief scientist for orbital debris, argues that the biggest concern is posed by small pieces of debris, which cannot now be tracked but can still destroy a satellite.
Apart from disasters like the 2009 Iridium-Kosmos satellite collision, we haven’t seen anything calamitous happen yet. Raymond Sedwick, an aerospace engineer at the University of Maryland’s Center for Orbital Debris Education and Research, thinks what is being done right now is effective for the most part, but he recognizes a growing concern that will have to be dealt with soon. “Some may argue that it’s already here or that it’s still decades away, but if you let it go until then, it might be too late,” he says.
According to Iyer, we are years away from really changing our approach to orbital debris. Most proposals have focused on three areas: improving protective measures, removing debris already in orbit (remediation), and preventing further accumulation of orbital junk (mitigation). Here’s a quick look at some of the technologies that may help.
he vessel, dubbed “Kounotori” (stork in Japanese), blasted off from the southern island of Tanegashima just before 10:27 pm local time (1327 GMT) attached to an H-IIB rocket.Japan launched a cargo ship Friday bound for the International Space Station, carrying a ‘space junk’ collector that was made with the help of a fishnet company.
There are estimated to be more than 100 million pieces in orbit, posing a growing threat to future space exploration, scientists say.
More than 50 years of human space exploration since the Soviet-launched Sputnik satellite in 1957 has produced this hazardous belt of orbiting debris.
Researchers are using a so-called electrodynamic tether made from thin wires of stainless steel and aluminium. The idea is that one end of the strip will be attached to debris which can damage working equipment—there are hundreds of collisions every year.