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NASA's Atlantis shuttle blasted off Monday with a haul of spare parts for the International Space Station and some microscopic worms that could explain muscle loss in space.
The shuttle and its six astronauts left Florida's Kennedy Space Center without a hitch for a 11-day voyage to deliver assorted gyroscopes, ammonia tanks and other equipment to the ISS.
"A perfect launch, right on time," said a spokesman for the US space agency as the crew reached orbit -- hurtling at a speed of more than 15,000 miles (24,000 kilometers) per hour.
With only five launches left before the 2010 retirement of the shuttle fleet, NASA officials said the parts were essential for extending the life of the space station, where the crew is due to dock on Wednesday.
"This flight is all about spares, basically, we're getting them up there while we still can," said mission director Brian Smith, "you'll see this theme in some of the flights that are going to come after ours as well."
This fifth and final shuttle mission for 2009 is scheduled to include three space walks to store hardware on the exterior of the space station and bring US astronaut Nicole Stott, who has been on the ISS since August, back to earth.
But the crew will also get to conduct some science, with the help of some ground-breaking worms.
Thousands of the microscopic creatures have been sent from Britain's University of Nottingham to study the effect of zero gravity on the human body's muscle development and physiology.
The worms will be stashed inside the Japanese Kibo laboratory on the ISS where they will be tested with several potential treatments for muscle loss.
Researcher Nathaniel Szewczyk said he hopes the worms, which suffer similar weight loss as humans, will pave the way for treatments to be safely tested on astronauts.
Atlantis' launch follows Friday's dramatic revelation that a "significant amount" of frozen water has been found on the moon, a discovery hailed by NASA as heralding a giant leap forward in space exploration.
NASA sent a missile crashing into the lunar surface last month, which kicked up lunar material that had not seen the light of day for billions of years -- including, the agency said, evidence of some two-dozen gallons of icy water.
Scientists had previously theorized that, except for the possibility of ice at the bottom of craters, the moon was totally dry.
Only 12 men, all Americans, have ever walked on the moon, and the last to set foot there was in 1972, at the end of the Apollo missions.
NASA has ambitious plans to put US astronauts back on the moon by 2020 to establish manned lunar bases for further exploration to Mars under a project called Constellation.
But NASA's budget is currently too small to pay for Constellation's Orion capsule, a more advanced and spacious version of the Apollo lunar module, as well as the Ares I and Ares V launchers needed to put the craft in orbit.
A review panel appointed by President Barack Obama said existing budgets are not large enough to fund a return mission before 2020.
The White House could still decide to extend the shuttle program through 2011 to reduce American reliance on Russia's Soyuz craft for transporting astronauts to the ISS.
As NASA awaits word of its fate, it is pressing ahead with plans that would allow humans to return to the moon.
Last month it successfully launched the prototype Ares I-X rocket.
