We can estimate the beginning of the Space age to be around the late 50's when the last stage of the rocket that launched Sputnik-1, remained in orbit.It has been in orbit since. Nearly 5000 space launches later we have an accelerating problem known as Space junk or space debris. This is the leftover damaged parts of satellites, spent rocket casings, defunct material along with other man made objects that orbit close to the Earth's surface. Nearly 70% of the low earth orbit which is roughly 2000 km above the planet will become un-usable for orbital launches unless something is not done soon to rectify the problem of Space Debris. The main concern about space debris is possible collision with active or functioning satellites or spacecraft.

 So what exactly is Space debris? Did you know it can be categorized into two types- natural and artificial. Natural space debris consists of small pieces of cometary and asteroidal material called meteoroids. We see these as meteors when they travel through the Earth's atmosphere.Artificial space debris is any non-functional man-made object in space (usually orbiting the Earth).

At a recent European Space Conference it was discussed that governments must start working towards the removal of orbital debris immediately before it becomes a catastrophic problem for satellites in the near future. As of now there is no written international law to tackle the issue. Also there is no agency involved in active removal of existing debris from orbit.

Space debris travels at 25000 km per hour so even a small object can puncture a hole and cripple a satellite in the low orbital region. 

The problem can be solved in a number of ways. 

• Objects in low altitude orbits (below about 500 km) are affected by atmospheric drag. This lowers their orbit until they re-enter the atmosphere and are thus naturally removed from orbit. The lower the orbit the faster it decays. 
• Space "tugs" could be employed to "catch" large space debris objects and either lower their altitudes for natural decay, or bring them back to Earth. 
• Giant "sponge" like objects could be deployed to "catch" or "soak up" small debris pieces. After a time, the sponge would be removed from orbit. 
• Attach tails or tethers to large pieces of space debris to increase the drag they experience and lower their orbits. 
• Use large ground based lasers to "push" small pieces of debris into lower orbits.

All of these schemes will be very expensive and use technology that is still to be developed.