CAPE CANAVERAL, Fla. — Even before the shuttle's return to space scheduled for today, Utah's ATK Thiokol began planning the next generation of space vehicles — and the following generation, all the way to rockets that could put humans back on the moon and lift loads weighing five times what the shuttle can now carry into space.

Only they're not entirely new, which is one of the big advantages of Thiokol's ideas. Some of these powerful space vehicles would be assembled from existing components, while other possibilities involve extensions of present designs.

"'Safe, simple and soon' is our theme" for the earliest of the new designs, the CEV or Crew Exploration Vehicle, said Mike Kahn, Thiokol vice president for Space Launch Systems.

If approved by NASA, the plans would ensure that Thiokol's Promontory plant near Brigham City would continue making human-rated solid-fuel rockets long beyond the scheduled end of the space shuttle program in 2010.

In January 2004, President Bush announced that the United States would return astronauts to the moon and eventually carry out landings on Mars.

About $11 billion in planned NASA spending over the next five years would be shifted into the program, and the administration would ask Congress to appropriate an additional $1 billion.

According to Bush's vision, the new CEV would be developed by 2008 and begin carrying astronauts by 2014.

To develop that capability quickly, Thiokol has been working with NASA on ways to use the existing shuttle system for the CEV.

The oomph to rocket astronauts into orbit, for example, could be produced with a standard solid stage booster as the first stage and "a liquid engine second stage" above that, Kahn said in a Deseret Morning News interview conducted last month at the Thiokol campus in Magna.

Among contenders for the second stage is the engine used for the upper stages of the Apollo moon rockets of the 1960s and early '70s.

"Basically, this will put a 50,000-pound payload into low-earth orbit, and it's human rated," Kahn said. That means the system would be safe to lift humans into space, not just satellites, because of high safety margins and redundancies built into the design.

Several options are being considered.

As with the shuttle, Thiokol's solid-fuel rocket boosters would be reusable after kicking a crew into space and separating from the crew capsule. The crew could then dock with the space station.

But there's another, more glamorous possibility.