Life, the Universe & Everything.

From the Radio Times:

Having already satirised reality TV, it was only a matter of time before the Doctor Who team turned their attention to the real-time format originated by 24. The Doctor and Martha are trapped aboard a spaceship in a distant galaxy. So far, so typical - but this particular ship is careering towards a boiling sun, and its crew are behaving oddly. The plucky duo have only 42 minutes to identify the saboteurs and save the day.

After the last preview, I (yet again) have high expectations of this episode. Part of the fun of the preview at the end of 'The Lazarus Experiment' was deciding which clips were from tonight's episode.