The scenario in which space debris collides and creates more debris is called Kessler Syndrome, named after the NASA ...

Nasa has been working on a range of technologies for astronauts to travel to and from Mars, which would take three years.

Mars is home to perhaps the greatest mystery of the solar system: the so-called Martian dichotomy, which has baffled scientists since it was discovered in the 1970s.

A collection of Martian rocks could reveal details about potential past life on the Red Planet – but first NASA has to get them back to Earth.