Sunday, March 27, 2016

Cygnus arrives at, berthed to International Space Station

The S.S. Rick Husband approaches the capture position below the International Space
Station. Photo Credit: NASA
After three days of travel to the International Space Station, the fifth Orbital ATK Cygnus spacecraft to visit the outpost was captured and berthed to the station early Saturday morning, March 26, delivering 7,756 pounds (3,518 kilograms) of food, supplies, and experiments.

Once the spacecraft was about 33 feet (10 meters) below the station, NASA astronaut Tim Kopra, the commander of the orbiting laboratory, took control of the space station’s robotic arm to move in and grab the free-flying Cygnus. Capture took place at 5:51 a.m. CDT (10:51 GMT) when the cargo freighter and ISS were about 250 miles (402 kilometers) over the south Indian Ocean.

“We’re really honored to bring aboard the S.S. Rick Husband to the International Space Station,” said Kopra. “It recognizes a personal hero of so many of us and this will be the first Cygnus honoree who was directly involved with the construction of this great station.”

Tim Kopra and Tim Peake work in the Cupola module to grab the free-flying Cygnus
from space. Photo Credit: NASA
After capture, ground teams spent the next two hours maneuvering the spacecraft to just below the Unity module of the orbiting lab. Once Cygnus was only inches away from the Earth-facing Common Berthing Mechanism, fine-tuning of the alignment began.

Getting the spacecraft below the CBM into the Ready To Latch position took a little longer than usual. Ground teams told the crew that because the robotic arm was fully stretched out, the procedure had to take place a little slower.

During final RTL alignments, the space station’s ground track took it away from video downlink. This caused the operators on the ground controlling the robotic arm to pause for about 30 minutes.

About an hour behind the timeline, berthing finally took place at 9:52 a.m. CDT (14:52 GMT) while the station was flying over the Pacific Ocean just west of Mexico.

The hatch between the station and Cygnus was opened the next day on Sunday. The crew will now begin the long process of unloading the thousands of pounds of cargo on board the spacecraft.

File photo of the Previous Cygnus berthed. This photo was taken during a space walk
earlier in the year. Photo Credit: NASA
“As we accomplish our fifth Cygnus berthing to the ISS, we celebrate the completion of a primary mission objective for OA-6,” said Frank Culbertson, President of Orbital ATK’s Space Systems Group via a company-issued release. “Our flexible Cygnus spacecraft has a lot of work left to do. Following its stay at the ISS, and for the first time, we will undertake three experiments [on board] the unmanned spacecraft.”

The vehicle is expected to remain attached to ISS for about two months (55 days) before being loaded with trash and unberthed on May 20. After departing the vicinity of the outpost, Cygnus will remain in orbit for eight more days to conduct the Saffire experiment.

Saffire will help scientists and engineers understand how fires spread in large areas on certain materials.

Cygnus was the first of three planned cargo ship arrivals in the next two weeks. A new Russian Progress spacecraft will launch on March 31 and is scheduled to dock on April 2. Then a SpaceX Dragon will fly atop a “full thrust” Falcon 9 on April 8, before being berthed to the Harmony module on April 10.

Together, some 12 tons (10.8 metric tons) of cargo will be delivered in arguably the busiest time in the space station program’s history.

Video courtesy of NASA TV
Time lapse by Trent Faust

Read more work by Derek Richardson and others at Spaceflight Insider.