Now 20-Feet Taller, Additional Main Engine

Following a nine-month design review of the rocket that will one day return US astronauts to the moon -- and, eventually, transport them to Mars -- on Wednesday NASA unveiled a bulked-up version of its proposed Ares V rocket.

The Associated Press reports the amped-up Ares is 20 feet longer than the previous version, now standing close to 38-stories tall. The rocket's first stage now sports six main engines instead of five, and the twin solid-rocket boosters attached to the stage will also be made larger, to hold more fuel.

All the changes are intended to allow Ares to carry heavier payloads, especially as the space agency looks to the Red Planet. In the new configuration, NASA says the upgraded Ares V will be able to haul over 156,600 pounds of cargo.

"We've looked at over 1,700 different Ares concepts," Ares program manager Steve Cook said. Major work on the Ares V will begin after the current space shuttle fleet is retired in 2010, he added.

Though comparable in size and scope with the mammoth Saturn V rocket that carried astronauts to the moon in the late 1960s and early 1970s (Ares V is now about 15 feet taller), there's one fundamental difference with the Ares V: it will not carry people into orbit, just their supplies and the lunar lander. The four-man crew will ride into orbit in the Orion space capsule atop the smaller Ares I rocket, and will then rendezvous with the departure stage containing equipment launched onboard the larger rocket.

The two-step design allows more equipment to be sent to the moon or Mars.

Constellation program manager Jeff Hanley told reporters Wednesday NASA remains on track for a manned lunar mission by 2020. "This extensive review proves we are ready for the next phase: taking these concepts and moving forward," he said.

FMI: www.nasa.gov/mission_pages/constellation/main/