US Dragon spacecraft returns to Earth from space station  

美国“龙”飞船脱离国际空间站

A commercial spacecraft operated by US space company SpaceX splashed down in the Pacific Ocean on Sunday afternoon, bringing back "critical" science samples from the International Space Station (ISS), US space agency NASA said.

The Dragon cargo spacecraft fell into the ocean about 480 kilometers west of Baja California, where it was retrieved by SpaceX engineers. The splashdown occurred at 3:05 p.m. EDT (1905 GMT), marking the end of the company's third contracted cargo resupply mission to the ISS.

Dragon reached the ISS on April 20 with about 5,000 pounds ( about 2,268 kg) of supplies aboard. The spacecraft was released from the ISS on Sunday morning.

According to the US space agency, a recovery boat will carry the spacecraft to a port near Los Angeles, where it will be prepared for a return journey to SpaceX's test facility in McGregor, Texas, for processing.

"Some cargo, including a freezer packed with research samples collected aboard the space station, will be removed at the port in California and returned to NASA within 48 hours," it said in a statement.

Dragon, the only ISS resupply spacecraft designed to return to Earth intact, carried over 3,500 pounds (about 1,588 kg) of NASA cargo and science samples from the ISS.

"The space station is our springboard to deep space and the science samples returned to Earth are critical to improving our knowledge of how space affects humans who live and work there for long durations," said William Gerstenmaier, associate administrator for human exploration and operations in NASA.

"Now that Dragon has returned, scientists can complete their analyses, so we can see how results may impact future human space exploration or provide direct benefits to people on Earth," Gerstenmaier said.

Investigations included among the returned cargo could aid in better understanding the decreased effectiveness of antibiotics during spaceflight while also improving antibiotic development on Earth, NASA said. Others could lead to the development of plants better suited for space and improvements in sustainable agriculture.

Meanwhile, a study known as T-Cell Activation in Aging experiment, which also launched to space aboard Dragon, seeks the cause of a depression in the human immune system while in microgravity. NASA said the research could help researchers develop better protective measures to prevent disease in astronauts.

SpaceX currently holds a 1.6-billion-US-dollar contract with NASA to fly 12 resupply missions to the ISS using the Dragon spacecraft and Falcon 9 rocket.

Besides SpaceX, NASA has also signed a deal with another private company called Orbital Sciences Corp. to supply cargo to the ISS.