CAPE CANAVERAL, Fla. -

SpaceX launched a Falcon 9 rocket Sunday night from Cape Canaveral to the International Space Station.

The rocket launched at 8:35 p.m. Sunday from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

Officials said the launch of the Dragon spacecraft will be the first of 12 contracted flights by SpaceX to resupply the space station and marks the second trip by a Dragon to the station, following a successful demonstration mission in May.

The Dragon will return about 734 pounds of scientific materials, including results from human research, biotechnology, materials and educational experiments, as well as about 504 pounds of space station hardware.

Officials said materials being launched on Dragon will support experiments in plant cell biology, human biotechnology and various materials technology demonstrations, among others planned for the station's Expedition 33 crew.

One experiment, called Micro 6, will examine the effects of microgravity on the opportunistic yeast Candida albicans, which is present on all humans. Another experiment, called Resist Tubule, will evaluate how microgravity affects the growth of cell walls in a plant called Arabidopsis. About 50 percent of the energy expended by terrestrial-bound plants is dedicated to structural support to overcome gravity. Understanding how the genes that control this energy expenditure operate in microgravity could have implications for future genetically modified plants and food supply.

Both Micro 6 and Resist Tubule will return with the Dragon at the end of its mission.

If all goes well, Dragon will attach to the complex on October 10 and spend over two weeks there before an expected return to Earth on October 28.

“We are right where we need to be at this stage in the mission,” said Elon Musk, CEO and Chief Technical Officer, SpaceX. “We still have a lot of work to do, of course, as we guide Dragon’s approach to the space station. But the launch was an unqualified success.”