The Orbital ATK Cygnus spacecraft, launched on April 18, has just reached the International Space Station and was captured by Canadarm2 robotic arm. Astronaut Peggy Whitson, assisted by her colleague Thomas Pesquet, will soon begin the slow maneuver to move the Cygnus until it docks with the Station’s Harmony node after about two hours.
Generally, cargo spacecraft take two or three days to reach the International Space Station but the Orb-7 mission’s started very close to the launch of the new crew members. For this reason, it was decided to leave the Cygnus in orbit for a little longer so that the full crew can proceed with its unloading operations.
The Orb-7 mission is almost accomplished because the Cygnus spacecraft can’t land and when it comes back into Earth’s atmosphere it will disintegrate. For this reason, it will be used to get rid of component failed or that can’t be used any longer on the International Space Station: all of that will be loaded on the Cygnus and will disintegrate along with it.
This final use of the Cygnus “John Glenn” spacecraft is normal for space cargo ships that can’t land. However, NASA will take advantage of this phase to continue a series of experiments called Saffire on the spread of fire in space. This will be the third test of this kind, hence the Saffire-3 name after the first two that were conducted on the previous Cygnus freighters.
Cygnus will leave the International Space Station in a few weeks. In these cases, an exact date for the cargo spacecraft departure is never given because it also depends on other tasks that can have higher priority. The preparation of the Saffire-3 experiment could also affect the departure date.
Tomorrow the International Space Station crew should open the Cygnus spacecraft’s hatch and at that point the cargo will be slowly brought to the Station. Subsequently, all that has now become garbage will be loaded on the Cygnus and the spacecraft will be ready for departure. These operations will continue slowly for several days.
This is the seventh of ten official missions established by the Orbital ATK’s contract with NASA to supply the International Space Station after the extension announced in March 2015. The next mission will be part of that extension and might start in October 2017 with the use of the Antares rocket.