When First satellite … Sputnik I … was launched on October 4, 1957 into space no one in the world would had ever thought that after couple of decades we will have to take serious measures to remove this Junk that we send in space !!! But at present , it is perhaps one of the most notorious thing that scientist are worried about …
Space itself is a very dangerous place , why ??? may be because here if you got into any troubles then you won’t find any hospital in near by few thousands miles 
… or worse , you even won’t be able to see or predict the incoming danger !!!
The danger i am talking about here is a very small parts of waste materials from satellites , some are parts of dead satellite … or dead satellite itself ( as you may know that satellites are then tend to be dead or fail time to time !!! ) … these junk is known as SPACE DEBRIS … it varies in size from a golf ball to say a football ?? … and it varies in form too … astronaut hand glove , camera , tools or toolbox or even garbage bags 
are some examples !!! The most talked space encounters that created space debris are , the most recent collision between IRIDIUM commercial satellite and Russian satellite which is the most discussed collision (BTW , speed of collision was 26,170 MPH !!! )… or anti-satellite weapon test by china … or same by USA … 
Now imagine that such an un-controlled element get hit to another working satellite … or to a guy who just got out of space shuttle to stretch his leg !!! or even worse … a shuttle in process of entering earth’s atmosphere !!! 
At present at U.N. , they don’t have any rule “forced” for this kind of space junking … so unfortunately there are no standards for it and it solely depends upon individual space agency and its budget ( leaving waste behind is cheaper then brining it back to recycle 
) … but there are some government organizations which look over and keep track of each of these debris such as Space Surveillance Network (SSN) part of US strategic air defense command center …
Upto today , there were no major considerable “encounters” with these debris have be met … but space studies shows that in near future if they don’t take any preventive measures then soon the nightmare will become true … so talked International Space Station is equipped with defensive shield from this kind of “encounter” … known as WHIPPLE SHIELD …
Image below shows population of debris view from out of geosynchronous orbit of earth … gives the idea of population in space !!!
Njoy …
