US deep space rocket moves into development phase

US space agency NASA said Wednesday that it has completed a rigorous review of the Space Launch System (SLS), the world's largest rocket under development to take humans beyond Earth orbit and to Mars.

The space agency also said it approved the program's progression from formulation to development, something no other exploration class vehicle has achieved since it built the space shuttle.

"We are on a journey of scientific and human exploration that leads to Mars," NASA Administrator Charles Bolden said in a statement. "And we're firmly committed to building the launch vehicle and other supporting systems that will take us on that journey."

The first test flight of the SLS rocket was originally scheduled for the end of 2017, but is now planned by November 2018, NASA said.

"The Space Launch System Program has done exemplary work during the past three years to get us to this point," said William Gerstenmaier, associate administrator for NASA's Human Explorations and Operations Mission Directorate. "We will keep the teams working toward a more ambitious readiness date, but will be ready no later than November 2018."

For its first flight test, the SLS rocket will be configured for a 77-ton lift capacity and carry an uncrewed Orion spacecraft beyond low-Earth orbit, said NASA.

In its most powerful configuration, the rocket will provide an "unprecedented" lift capability of 143 tons, which will enable missions even farther into our solar system, including such destinations as an asteroid and Mars, it said.

NASA said it plans to spend 7.021 billion US dollars on building the 77-ton version of the SLS between this year and the first launch. NASA is also developing the Orion spacecraft to carry astronauts, whose first unpiloted test flight is targeted for December this year, and a launch pad and other ground systems for deep space missions.