After the successful launch of Cygnus last week we were expecting the spaceship to arrive on Sunday. The weekend plans were uploaded and all teams and activities involved with the capture of the space vehicle were ready to go.
Control centres check the final approach several times that all systems are ready as there is no room for errors. A space ship weighing several tons approaching the International Space Station has to operate perfectly so that there is no risk for collision. Both the Space Station and Cygnus use data that is provided by navigation satellites, similar the ones we use in car navigation. The control centres monitor and control those systems to ensure everything is absolutely correct before we allow a space ship to get close to the orbital outpost.
Unfortunately a mismatch of some data was detected and the planned arrival of Cygnus on Sunday was delayed. The space ship is now approximately 4 km away from the Space Station and has to wait until corrections are made before it can continue its final kilometres.
We hope it will happen soon and Luca can operate the robotics arm to capture the Cygnus spacecraft and berth it to the Space Station.
In the meantime the next Expedition is getting ready for its launch with the Soyuz 36S on Wednesday at 20:59 GMT and shall arrive approximately six hours after launch.