Nasa Mars atmosphere mission ready for launch

Nasa's Maven mission launches on Monday, aimed at studying how and why Mars lost its atmosphere, once thought to be similar to Earth's.

The spacecraft will orbit at about 4,000 miles (6400 km) above the planet for a year, recording changes in its atmosphere.

Evidence suggests Mars was once shrouded in a thick blanket of gases that supported the presence of liquid water at its surface, but air pressure is now too low.

Pallab Ghosh reports.