Nasa scientists: 'Life outside of Earth is probably going to be really hard to find'

In previewing missions in the search for life and discussing its challenges, the scientists confess they 'can't even agree on a definition of what life detection is'

Nasa scientists previewed several missions in the search for life off Earth on Tuesday, including a plan to scoop up minerals from an asteroid and one to drill into the surface of Mars.

The missions described by researchers included satellites, spacecraft, landers and work concentrated on Mars, Jupiter moons, an asteroid and on Earth itself.