THE SCIENCE OF IMAGING EARTH

ESA astronaut Paolo Nespoli gives his perspective on the utility of ISS photography

“The photos we take in space by hand are mostly artistic, but in some cases we are asked to take specific pictures. I remember photographing a city from a side-on position, and you could actually see and measure the depth of the pollution that was covering it. This is something that you can’t really see in a picture taken overhead by a satellite. Also, you can pick up certain details by eye that might not be so obvious from a satellite. Then, once you know what you are looking at, the satellite can focus in on the object better than you can with your handheld camera.

There was a case that happened with a crew before me, who noticed a volcano erupting on Earth. Nobody on Earth knew this was happening, but the astronauts were able to pick it up from space. It wasn’t dangerous because there were no people living around the volcano, but the ashes could have disrupted airline travel so it was good that the crew discovered it first. I also experienced something similar myself with photos I took of islands in the Pacific. A few months later I found a scientific paper online that had used my pictures, revealing that an island I had photographed was actually an erupting volcano that nobody knew about!

We achieve scientific results with our own photos more by chance, but I think it puts a personal touch on the images when they are taken by people. Observing Earth from this distance helps us remember that the things we do have an effect; things that happen in the UK can change the climate in France, for example, which is something that you don’t really think about. Through the eyes of an astronaut, these issues become more apparent to the general public, and I think this does have some sort of influence on the world.”