Mission Orb-6 accomplished: the Orbital ATK Cygnus spacecraft has reached the International Space Station

The Cygnus
The Cygnus “Rick Husband” spacecraft about to be captured by the Canadarm2 robotic arm (Image NASA TV)

The Orbital ATK Cygnus spacecraft, launched on March 23, has just reached the International Space Station and was captured by the Canadarm2 robotic arm. Astronaut Tim Kopra, assisted by his colleague Tim Peake, will soon begin the slow maneuver that will move the Cygnus until it docks with the Station’s Harmony node after about two hours.

The Orb-6 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 “Rick Husband” spacecraft is normal for space cargo ships that can’t land. However, NASA will take advantage of this phase to begin a new series of experiments called Saffire on the spread of fire in space. This will be the first test of this kind, hence the Saffire-1 name.

Cygnus will leave the International Space Station in a couple of months or so. In these cases, an exact date for the cargo spacecraft leaving is never given because is also depends on other tasks that can have higher priority. The preparation of the Saffire-1 experiment could also affect the departure date.

Tomorrow the crew of the International Space Station 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 a few weeks.

This is the fifth of ten official missions established in the Orbital ATK’s contract with NASA to supply the International Space Station after the announced extension in March 2015. The launch seemed to have been flawless, instead there was a thriller moment because it turned out that the Atlas V rocket’s first stage emgines went off five seconds early. It seems a marginal difference but those are the moments of maximum thrust and every second counts a lot.

The causes of this anomaly haven’t yet been clarified and ULA’s engineers are studying the telemetry data because they need to understand them, also in view of the Atlas V’s next launches. The next launch was scheduled for early May but it’s been temporarily suspended. In the Cygnus launch, the engine of the Centaur upper stage had a burn about a minute longer to make up for the anomaly.

The Atlas V rocket’s flexibility allowed the cargo “Rick Husband” to enter its proper orbit determining the success of its Orb-6 mission. The next mission of the Cygnus spacecraft is tentatively scheduled for June 2016 and the launch should take place on the new version of the Orbital ATK Antares rocket.

Close-up of the Canadarm2 robotic arm capturing the Cygnus spacecraft (Image NASA TV)
Close-up of the Canadarm2 robotic arm capturing the Cygnus spacecraft (Image NASA TV)

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