A new rocket that would combine parts from NASA’s canceled Ares I rocket as well as the Ariane 5, a well-proven European satellite launcher, could provide a low-cost option for taking crew and cargo to the space station.

The rocket proposal was announced this week by ATK, an aerospace and defense company that manufactures the solid rocket motors for NASA’s space shuttles, and Astrium, the European company that makes the Ariane 5. They say the rocket, called Liberty, would be ready for flight by 2015.

The Liberty’s main advantage is that it is built on existing technology. For its lower stages the rocket will use a version of the solid rocket boosters designed by ATK for the Ares I, the rocket NASA was building to replace the space shuttles. Ares I was part of the Constellation program to return humans to the moon, which was canceled by the Obama administration in favor of a new course relying on the commercial sector for transportation to low-Earth orbit. Liberty would also be much cheaper than the Ares I because it’s upper stage it would use the first stage of the Ariane 5, which has been launched successfully 41 consecutive times.

Charlie Precourt, a former shuttle astronaut who is vice president and general manager of ATK Space Launch Systems, in Aviation Week:

“We will provide unmatched payload performance at a fraction of the cost, and we will launch it from the Kennedy Space Center using facilities that have already been built. This approach allows NASA to utilize the investments that have already been made in our nation’s ground infrastructure and propulsion systems for the space exploration program.”

ATK and Astrium are also building the rocket to carry a larger payload to low-Earth orbit than the Atlas V, which is built by United Launch Alliance. Other commercial companies, including Boeing and Orbital Sciences Corporation, are looking to use low-end versions of the Atlas V to carry the capsules they are building. Liberty could carry any capsule at a cost less than that of the Atlas V, according to ATK.

The companies have entered the rocket into the second round of NASA’s Commercial Crew Development program, a $200 million competition. Liberty’s first test flight would be in 2013.