Several missions this year are seeking out life on the red planet. But would we recognize extraterrestrials if we found them?
Tiny piece of meteorite from London’s Natural History Museum will be used by rover exploring red planet
What do you ask the man who knows everything? The theoretical physicist and bestselling author answers questions from famous fans and Observer readers
Not since the 1960s have we witnessed such appetite for space missions. Here’s what to expect in the year ahead, from commercial launches to Chinese ambitions