The U.S. space agency NASA has announced plans for its next line of rockets that will carry astronauts into space now that the space shuttles have been retired.

NASA chief Charles Bolden unveiled plans for the $35 billion Space Launch System Wednesday, saying NASA is taking U.S. President Barack Obama's challenge to “be bold and dream big.” The first rocket is expected to be built and test-launched by 2017.

The rockets will be designed to carry a human crew in a capsule at the top, in a return to rocket designs of the past. NASA says it will be able to carry up to 100 metric tons of cargo, and later versions of the rockets will be able to carry as much as 130 tons, far more than the space shuttles.

NASA officials say the rockets will be the most powerful craft since the Saturn Five rocket that carried the U.S. Apollo astronauts to the moon. Bolden said Wednesday he expects future space explorers to “dream of one day walking on Mars.”

NASA's 30-year space shuttle program ended earlier this year.