go to Mars

The launcher, which will take until 2017 to build, will fill a gap in US manned flight program created by the retirement of the last US space shuttle in July after. The project would cost $10 billion through 2017, another
$6 billion to build the Orion deep-space crew capsule and another $2 billion to refurbish Nasa's Florida spaceport to accommodate the new rocket.

But Nasa said it will be far more powerful, capable of carrying much larger payloads beyond low-Earth orbit deep into space, and eventually to Mars.

Charles Bolden, the Nasa chief, made the announcement of the design for the new Space Launch System, which the space agency touted as the most powerful rocket since the Saturn V rocket put US astronauts on the moon.

"President Obama challenged us to be bold and dream big, and that's exactly what we are doing at Nasa," said Mr Bolden. "While I was proud to fly on the space shuttle, tomorrow's explorers will now dream of one day walking on Mars."

The first test launch is scheduled for 2017 followed by manned flights in 2021.