OA-9 Cygnus cargo ship arrives at ISS
Orbital ATK’s OA-9 Cygnus cargo spacecraft rendezvoused with the International Space Station May 24, 2018, after a three-day chase of the orbiting outpost following a successful launch atop an Antares rocket.
When the OA-9 Cygnus spacecraft, named S.S. J.R. Thompson, was within about 33 feet (10 meters) of the football field-sized complex, Expedition 55 Flight Engineer Scott Tingle of NASA used the robotic Canadarm2 to reach out and grab the vehicle. The official grapple time was 5:26 a.m. EDT (09:26 GMT) while the outpost was flying some 264 miles (425 kilometers) over the southern Indian Ocean.
“Excellent job guys,” said Capcom Cindy Koester at NASA’s Mission Control Center in Houston. “You’ve got a whole team down here in Houston with big smiles on their faces.
Koester said she can say the same for the Orbital ATK team, which is operating Cygnus from its control room in Dulles, Virginia.
“Thank you,” Tingle said. “It was a beautiful day to grapple a spaceship.”
Over the next several hours, ground teams remotely commanded the robotic arm to move the 20.9-foot (6.4-meter) long spacecraft to the Earth-facing port of Unity module. There, controllers carefully positioned the vehicles active Common Berthing Mechanism below the modules passive version and carefully connected them.
Once properly aligned, a series of bolts were commanded to drive into place to secure the spacecraft to the ISS at about 8:13 a.m. EDT (12:13 GMT). The next steps will be for the vestibule—the area between the hatch of the Cygnus and ISS module—to be checked for leaks and pressurized.
After those tasks are completed, the crew is expected to open the two hatches and enter the 953-cubic-foot (27-cubic-meter) volume of the Pressurized Cargo Module, which contains some 7,400 pounds (3,400 kilograms) of crew supplies, science experiments and a number of CubeSats for future deployment.
On approach to the ISS, the Cygnus spacecraft tested out a new communications radio called the Common Communications for Visiting Vehicles (C2V2). This is expected to be used for future commercial crew vehicles and eventually other visiting vehicles bound for the U.S. segment of the outpost.
Also expected to be performed, albeit late in the spacecraft’s two-month stay, is a test of Cygnus’s potential reboost capability. According to NASASpaceflight, this particular test is expected to involve the spacecraft briefly firing its single main engine for several seconds and is not expected to change the station’s orbit in any meaningful way.
Once the mission of OA-9 Cygnus is completed, the cargo spacecraft is expected to be loaded with thousands of pounds of trash and other unneeded equipment. In mid-July, it is expected to be unberthed and released. It should then perform a departure burn and slowly drift away from the ISS.
Then, sometime before the end of July, Cygnus should perform a de-orbit burn and re-enter Earth’s atmosphere over the southern Pacific Ocean. Because it is not designed to be recovered, the spacecraft will break apart with any surviving pieces safely falling into an area of the ocean with little-to-no sea traffic.
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.