The engine firing provided a slingshot-like boost to the Orion capsule, speeding it up to some 25,000 mph, the velocity needed to break free of Earth's gravitational clasp for a trek to the moon.

After nearly seven hours, the astronauts' lunar observation period is wrapping up.

By doing so, their Orion spacecraft travelled more than 250,000 miles from Earth - a new record for the furthest distance humans have ever travelled into space.