Nasa has approved construction of the world's most powerful rocket designed to take astronauts to Mars.

The $7bn (£4.2bn) Space Launch System (SLS) is scheduled to blast off for a test launch in November 2018.

It will potentially take humans to the red planet for the first time by the 2030s.

Nasa administrator Charles Bolden said: "We are on a journey of scientific and human exploration that leads to Mars.

"And we're firmly committed to building a launch vehicle and other supporting systems that will take us on that journey."

The SLS will have a lift capacity of up to 143-tonnes which means it can travel deep into the solar system.

Nasa's associate administrator Robert Lightfoot said: "Our nation is embarked on an ambitious space exploration programme, and we owe it to the American taxpayers to get it right.

"After rigorous review, we're committing today to a funding level and readiness date that will keep us on track to sending humans to Mars in the 2030s – and we're going to stand behind that commitment."

The funding was approved after a smaller model of the rocket passed an internal review.