4: Nasa to test 'sleep-inducing lights'

Researchers at Kennedy Space Center are already
testing an SSLM lighting unit

Nasa is to test colour-changing lights on the International Space Station (ISS) as part of efforts to help astronauts on board sleep.

The US space agency will initially swap a fluorescent panel with a solid-state lighting module (SSLM) containing LEDs which produces a blue, whitish or red-coloured light depending on the time.

It says the move may help combat insomnia which can make depression, sickness and mistakes more likely.

The test is due to take place in 2016.