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OA-6 Cygnus released, Saffire experiment set to begin

Cygnus OA-6

Cygnus just before capture by the robotic Canadarm2 in March 2016. Photo Credit: NASA

The S.S. Rick Husband Cygnus cargo ship was detached from the International Space Station (ISS) today after just over 11 weeks attached to the orbiting outpost. The spacecraft was commanded to be released at 8:30 a.m. CDT (12:30 GMT) on June 14 by NASA astronaut and ISS Commander Tim Kopra.

Over the last couple of weeks, the Orbital ATK-built spacecraft was loaded with 4,087 pounds (1,854 kilograms) of unneeded equipment, trash, as well as a few post-space station operations experiments.

“We [want] to congratulate the entire Cygnus team for a very successful mission of the S.S. Rick Husband,” Kopra said. “We’re very grateful that we’ve had the supplies and science to sustain our mission here on the International Space Station.”

Cygnus as it approached the International Space Station March 23, 2016. Photo Credit: NASA

Cygnus as it approached the International Space Station March 23, 2016. Photo Credit: NASA

The hatch between Cygnus and the Earth-facing port of the Unity module was closed yesterday morning. Earlier this morning—shortly before 6 a.m. CDT (11:00 GMT)—with the robotic Canadarm2 firmly attached to the grapple fixture at the bottom of the cargo ship, the bolts connecting the ISS with the spacecraft were disconnected.

About 45 minutes later, Canadarm2 was commanded to move Cygnus from its berthed position to the release position. Kopra gave the command to detach the arm from the spacecraft and move it away at 8:30 a.m. CDT (12:30 GMT). Both vehicles were flying about 254 miles (408 kilometers) over southern Paraguay at the time.

A few minutes later, the first command was given for the Cygnus to move away from the outpost and out of the Keep-Out Sphere—an area of around 656 feet (200 meters). At 8:51 a.m. CDT (12:51 GMT), the spacecraft exited the approach ellipsoid. This concluded joint operations between NASA and Orbital ATK.

Cygnus will be in free-flight around the Earth for the next eight days, with ground teams activating remote experiments—one of which requires a safe distance from ISS. The Saffire-1 experiment is a NASA study to test flammability and fire propagation in space.

Fires have been purposely lit in microgravity before, but nothing the size of this experiment. Previous experiments have been no more than four inches (10 centimeters) in size; this study has an area of 12 by 36 inches (30 by 91 centimeters) inside a specially-built container.

The experiment was designed at the Glenn Research Center and will show how large and fast a fire can spread. It will be remotely ignited onto cotton and fiberglass material. Sensors will gather data as well as high-definition video.

The fire will start sometime Tuesday afternoon on June 14. The first pieces of data will be sent back beginning around 7 p.m. CDT (midnight GMT). HD Footage of fire will be available to view no earlier than tomorrow. Saffire experiments will be sent aboard the next two Cygnus spacecraft to fly to space.

This Cygnus was launched atop an Atlas 5 rocket on March 23. It berthed with the station about three days later bringing with it 7,745 pounds (3,513 kilograms) of cargo to the orbiting outpost.

After all the data from post-unberthing experiments are downloaded, the spacecraft will be commanded to re-enter Earth’s atmosphere to burn up. That will occur on June 22 over the southern Pacific Ocean.

The next Cygnus, named S.S. Alan Poindexter, will launch atop Orbital ATK’s newly upgraded Antares rocket. In October 2014, the last Antares exploded shortly after launch, destroying both the rocket and Orb-3 Cygnus spacecraft. The new Antares will launch on July 6, 2016, at 12:49 p.m. EDT (16:49 GMT) from the Mid-America Regional Spaceport in Wallops, Virginia.

Video courtesy of SciNews


Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.

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