Nasa's giant new space rocket designed to send humans into deep space has passed a critical independent review.
The Space Launch System (SLS) is designed to power the agency's missions in space for the next several decades.
Nasa said it will take humans to the Moon, Mars and "destinations even farther across our solar system".
The SLS will launch the Orion spacecraft and other payloads, and should form the basis for a brand new era of space exploration - funding pending, of course.
The Nasa review looked at the performance, costs and schedule requirements to develop and build the heavy-lift rocket.
It was confirmed by the review board that it can now move from the concept stage to preliminary designs.
That might sound like Nasa is taking its time - but it says the program is moving rapidly.
The SLS program was only launched 10 months ago, and the first test flight for the new rocket is scheduled for 2017.
It will start with a lift capacity of 70 tons, and will eventually evolve to a three-stage rocket which can lift 130 tons, enabling support for deep space exploration (including potentially a manned mission to Mars).
"This is a pivotal moment for this program and for Nasa," said SLS Program Manager Todd May.
"This has been a whirlwind experience from a design standpoint. Reaching this key development point in such a short period of time, while following the strict protocol and design standards set by Nasa for human spaceflight is a testament to the team's commitment to delivering the nation's next heavy-lift launch vehicle."