The simple answer: too much. It is extremely difficult to calculate or observe how much there actually is, but the latest numbers have found more than 20,000 objects larger than ten centimetres (four inches) being tracked, and an estimated 500,000 objects larger than one centimetre (0.4 inches), not to mention over 100 million objects smaller than one centimetre (0.4 inches).
Due to the high speeds of these objects even tiny debris can seriously damage operationalspacecraft. The amount of debris left over in orbit around the Earth is becoming a significant concern for many organisations and governments.
If the 1,000 active satellites were lost the replacement cost is estimated at around $130 billion (£86 billion), and that is without considering the knock-on effects on wider society. With this in mind, there have been many proposed missions to help clean up debris from around the Earth.
One of the more popular ideas is a space harpoon; a ‘chasing’ satellite could harpoon larger debris before dragging it down to burn up in Earth’s atmosphere. Whether this design works or not, this type of space mission will certainly see great advances over the next five to ten years.