Wrapping up SpaceX’s fourth operational resupply flight to the International Space Station, a Dragon cargo capsule departed the high-flying research complex Saturday, dropped out of orbit and descended to a parachute-assisted splashdown in the Pacific Ocean west of Baja California with nearly 3,300 pounds of biological specimens and hardware.
The spaceship’s return to Earth marked the end of a nearly five-week mission — the fourth such flight in SpaceX’s $1.6 billion contract with NASA covering 12 round-trip resupply runs to the space station.
Operating on commands issued by mission control in Houston, the space station’s Canadian-built robotic arm pulled the Dragon supply ship from a berthing port on the Harmony module, where it arrived Sept. 23 after a two-day pursuit following launch aboard a Falcon 9 rocket from Cape Canaveral.
The Dragon spacecraft was removed from the Harmony module around 8 a.m. EDT (1200 GMT), then the robot arm maneuvered the capsule to a release position 30 feet below the space station SpaceX flight controllers in Hawthorne, Calif., readied the ship for departure.
Astronauts Reid Wiseman released the robot arm’s grasp on the Dragon cargo craft, allowing the ship to fly free at 9:57 a.m. EDT (1357 GMT).
Three rocket firings guided the Dragon spacecraft away from the space station, and the capsule was expected to close a door to its navigation bay around 1:30 p.m. EDT (1730 GMT) to set up for re-entry.
The spaceship’s Draco thrusters ignited at 2:43 p.m. EDT (1843 GMT) to slow the capsule’s speed enough to fall out of orbit, then the craft was programmed to jettison an expendable unpressurized trunk section with Dragon’s solar panels to burn up in the atmosphere.
Cocooned inside an ablative heat shield jointly developed by NASA and SpaceX, the 12-foot-diameter gumdrop-shaped landing module plunged into the upper layers of the atmosphere, generating intense heat approaching 3,000 degrees Fahrenheit from friction as it flew across the Pacific Ocean at hypersonic speeds.
Approaching the splashdown zone from the southwest, the spacecraft deployed a pair of drogue parachutes then unfurled a trio of 116-foot-diameter orange and white main chutes to slow the capsule’s descent to roughly 11 mph.
The capsule reached the Pacific Ocean at 3:39 p.m. EDT (1939 GMT), according to NASA, settling in the sea about 265 miles west of Baja California.
The mission lasted 34 days, 13 hours and 49 minutes from blastoff to splashdown, the longest Dragon flight to date.
The Dragon cargo craft came back to Earth with 3,276 pounds of equipment, including blood and urine samples harvested from astronauts and plants grown aboard the space station. The supply freighter was also expected to bring home mice launched last month to test out animal habitats in space and study muscle atrophy in microgravity.
The space station crew packed the cargo for return to Earth while the Dragon capsule was attached to the orbiting laboratory.
The Dragon freighter is the only spacecraft capable of returning sizable cargo from the space station back to Earth.
On its flight up to the station, the Dragon spacecraft carried nearly 5,000 pounds of supplies — food, spacesuit batteries, experiments, a 3D printer, and a deployer designed to hurl small satellites into orbit from the complex.
The mission also delivered a $26 million ocean winds sensor, which scientists have already activated to help improve hurricane forecasting and climate research.
“This mission enabled research critical to achieving NASA’s goal of long-duration human spaceflight in deep space,” said Sam Scimemi, director of the International Space Station division at NASA Headquarters. “The delivery of the ISS RapidScatterometer advances our understanding of Earth science, and the 3D printer will enable a critical technology demonstration. Investigations in the returned cargo could aid in the development of more efficient solar cells and semiconductor-based electronics, the development of plants better suited for space, and improvements in sustainable agriculture.”
A SpaceX recovery team was waiting for the Dragon’s splashdown in the Pacific Ocean. A crane will hoist the capsule out of the sea and onto the deck of a 150-foot vessel for transport back to a port near Los Angeles.
NASA said time-sensitive biological samples contained inside refrigerators aboard the Dragon spacecraft will be handed over to scientists by SpaceX within 48 hours. The rest of the cargo will be removed and given to NASA once SpaceX takes the capsule to the company’s test facility in Central Texas.
NASA contracted with SpaceX and Orbital Sciences Corp. to ferry supplies to the space station after the retirement of the space shuttle.
Orbital’s Cygnus cargo-hauler is set for launch Monday aboard an Antares rocket from Wallops Island, Va. It will reach the space station Nov. 2.
A Russian team is preparing a Progress supply ship for liftoff Wednesday from the Baikonur Cosmodrome. The Progress cargo capsule will dock to the space station the same day, taking the place of another Progress vehicle due to leave the complex Monday.
Another member of the space station’s fleet of resupply freighters — the European Space Agency’s Automated Transfer Vehicle — is also docked to the back end of the outpost’s Russian Zvezda service module, providing propulsive support to steer the 450-ton complex in orbit.
SpaceX’s next Dragon mission to the space station is expected to launch around Dec. 9 with another load of fresh supplies.
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