Northrop Grumman's Cygnus spacecraft prepares to end a roughly 40-hour journey to catch up with the International Space Station. launch The spacecraft lifted off from Cape Canaveral Space Force Station aboard a SpaceX Falcon 9 rocket Sunday afternoon and is scheduled to arrive at the orbiting outpost Tuesday morning.
According to NASA, the Cygnus spacecraft is on track for capture and the start of the docking process at 3:10 a.m. EDT (0710 UTC). NASA astronaut Matthew Dominick will control the Canadarm2 robotic arm during the operation and fellow Crew 8 astronaut Jeanette Epps will serve as backup.
Once Cygnus is captured, control of Canadarm2 will be handed over to ground controllers to complete the docking process with the Earth-facing port of the Unity module.
The timing of the capture operation was called into question shortly after launch when NASA said Cygnus failed to complete the first “target altitude injection,” or TB1, which was scheduled for 11:44 a.m. EDT (1544 UTC), less than an hour after liftoff. In a Sunday night interview blog entryThe agency said this was due to “a late entry into the burn sequence.”
The update indicated that a second attempt on TB1 scheduled for 12:34 p.m. EDT (1634 UTC) that day was aborted by the spacecraft “shortly after engine ignition due to a slightly low initial pressure state.”
In one part blog entry On Monday, NASA said the Cygnus spacecraft was able to complete “two delta rate burns,” allowing it to remain on track for capture Tuesday morning. It said the reason for the aborted burns turned out to be “due to a slightly low initial pressure reading detected by Cygnus’ onboard sensing system.”
“Engineers at Northrop Grumman’s Mission Control Center in Dulles, Virginia, evaluated the pressure reading, confirmed it was acceptable and reworked the burn plan to reach the space station on the originally planned schedule,” a NASA spokesperson wrote, adding that “the spacecraft is on a safe trajectory and all other systems are operating normally.”
Gold capture
On the eve of the launch of the Cygnus spacecraft on August 4, the Canadian Space Agency (CSA) announced that this will be the 50th “cosmic capture” of a cargo craft for Canadarm2, formally the “Space Station Remote Manipulator System” (SSRMS). The first such operation took place on September 17, 2009, when it captured the Japan Aerospace Exploration Agency (JAXA) spacecraft HTV-1.
It would go on to receive a total of nine H-2 transfer vehicles (HTVs), 20 Cygnus spacecraft, and 20 Cargo Dragon spacecraft in the lead-up to receiving the NG-21 vehicle.
The 17-metre-long (56 ft) arm was built by MacDonald, Dettwiler and Associates Ltd. (MDA Space) in Ontario, Canada, and launched to the ISS during Space Shuttle mission STS-100 in April 2001. The arm is still managed by MDA Space with funding from CSA.
