The space shuttle Discovery has landed after completing a 14-day mission to deliver part of a Japanese science laboratory to the International Space Station. VOA's Brian Wagner has this report from Miami.

The seven astronauts aboard the shuttle Discovery touched down near mid-day Saturday at the Kennedy Space Center in Florida. Astronaut Garrett Reisman returned to Earth after spending some three months at the International Space Station, where Gregory Chamitoff now takes his place.

Commander Mark Kelly led the shuttle mission, which included three space walks and the installation of a new science module to the space station. "We had a great mission that, from our point of view, was very successful," said Kelly. "We are really glad to be involved in making the space station a bigger and more capable place."

The Discovery crew delivered the main component of the Japanese-built Kibo space module - a pressurized chamber for astronauts to conduct experiments on how the human body and equipment react to conditions in space.

NASA associate administrator Chris Scolese said many of those experiments will help the space agency understand the challenges of launching manned missions to Mars, planned in coming years.  "We need to learn how to work and operate in space," said Scolese. "That's exactly what we are learning how to do on the space station. How to build things, how to fix things. We have to learn how to work in a microgravity environment."

Discovery's scheduled landing was placed in doubt on Friday, when astronauts noticed a metal piece floating away from the orbiter. NASA engineers later determined the missing part posed no danger for re-entry and landing.

The next shuttle mission is scheduled for October, when Atlantis will visit the Hubble space telescope to replace aging parts and install new equipment. It will be the final shuttle mission to Hubble before NASA retires the shuttle fleet in 2010.