Since the beginning of the space age, with the launch of Sputnik in 1958, we have launched thousands of rockets carrying more than ten thousand satellites into space.

The last few years have seen a dramatic increase in these numbers, and over the last few decades there has been a change in the type of mission flown, with private companies (yellow) launching smaller satellites than those launched by non-commercial agencies (blue).

This graph, created in a joint project between ESA and the UN, also shows the number of unregistered objects (red) has increased in recent years. It should be noted that these are objects not yet registered with the UN, and registration rates are expected to increase.

In episode 4 of the ESA-UNOOSA space debris series, Ian Freeman and Francesca Letizia discuss what these changes mean for the future of spaceflight and the creation of space debris.