Cygnus SS Alan Poindexter, cargo spacecraft by Orbital ATK, separated yesterday from Unity nadir docking port and begun its ultimate one week mission.
It is the end of OA-5 mission lasting for 34 days since October 17, when Cygnus OA-5 was delivered to orbit by Antares 230 rocket from Mid-Atlantic Regional Spaceport LP-0A launch site. After docking to Unity module on October 23 it begun its stable phase of mission remaining attached to International Space Station. It was carefully unpacked and after over three weeks procedure of departing begun. Astronauts started to fill space inside Cygnus with unwanted equipment, trash , used or broken parts and anything what used precious space of ISS interior. Next Canadarm2 robotic arm grabbed Cygnus in the beginning of last week. Hatch was closed and sealed on Thursday and all systems joined by ISS and Cygnus were shut down and separated.
Procedure of separation was done by commander Shane Kimbrough with Flight Engineer Thomas Pesquet as backup, remaining inside Cupola module and supervised by Orbital ATK’s control center in Dulles and Johnson Space Center’s Mission Control Center. Early in the morning on Monday, 21 November, bolts of docking port were released and Canadarm2 moved Cygnus to the position where it was waiting for releasing command from console inside Cupola module. Final moment of the separation was done at 13:22 UTC during passing over Pacific Ocean on altitude of 400 km. Cygnus slowly moved away from Station and started its engines for 3 minutes to enter Approach Ellipsoid. After reaching this point Cygnus went under control of Orbital ATK Mission Control Center in Dulles and started its lasting one week research mission with experiments inside, which were too dangerous to perform inside ISS.
Main tasks for Cygnus are initialization and performing SAFFIRE-II experiment and deploying four Lemur-2 satellites later this week (on Friday). SAFFIRE-II is second from series of experiments devoted to observation of fire dynamic in low gravity. It was initiated yesterday at 18:30 UTC and already ended. Data gathered by cameras and sensors will be transmitted to Earth in following days. Deploying four Lemur-2 satellites is planned for Friday after orbit raising maneuver (two burns will increase orbit for 100 km) on 25th November. Separating of first pair is planned for 21:05 UTC on Friday and second pair will be released at 01:05 UTC on 26th November. Last day of the mission will be finished with activation of BE-4 engine and conducting orbit reduce maneuver to enter atmosphere later on 27th November.