A European spacecraft spearheading a trail-blazing search for life on Mars is on track to reach the Red Planet in October.
ExoMars Trace Gas Orbiter (TGO), launched on March 14, has already completed more than half of its 500 million km (310.6 million mile) journey through space.
On Thursday the craft automatically fired its main rocket engine for 52 minutes, setting it on course to intercept Mars on October 19.
TGO is the first of two ExoMars missions that will make the first definitive search for traces of past or present life on Mars.
The orbiter is designed to analyse rare gases in the planet's atmosphere, especially methane, which can be a by-product of life.
It will also deploy a robot lander called Schiaparelli which will test the descent technology needed for the second mission.
ExoMars Rover, due to launch in 2020, will carry a six-wheeled vehicle to the planet equipped to drill beneath the surface and analyse samples for molecular signs of life.
The deep space engine burn was closely monitored by European Space Agency mission controllers in Darmstadt, Germany.
Deputy spacecraft operations manager Silvia Sangiorgi said: "The engine provides about the same force as that needed to lift a 45kg weight in a fitness studio, and it ran for about 52 minutes, so that's quite a significant push."