Sunday 29 September 2013

ISS and Cygnus

On September 18, Orbital Science Corporation launched an Antares rocket from Wallops, with the Cygnus COTS demo as payload. Just like SpaceX-es Dragon, the Cygnus is a commercial cargoship built to bring cargo to the ISS as part of  the Commercial Orbital Transportation Services (COTS) initiative. The September 28 launch is the inaugural demonstration flight of the Cygnus.

Initially Cygnus was to dock with the ISS on September 22nd, but a communication problem between the ISS and the Cygnus board computer caused a delay. Next the launch and docking of Soyuz TMA-10M bringing a new astronaut crew to the ISS on September 25 intervened, with the result that the Cygnus docking was rescheduled for September 29th.

click image to enlarge

In the early morning of September 29th, around 4:01 UT (6:01 am local time), ISS and the Cygnus COTS demo cargoship made a 40-degree pass in the southern sky as seen from Leiden. I had no idea how close the pair would be before actually observing the pass. It turned out to be close, the two spacecraft passing some 15 seconds after each other. The ISS was leading, Cygnus following.

Shortly after emerging from eclipse, the Cygnus was reasonably bright (mag. +3) and visible by the naked eye. But it quickly lost brightness, and by the time the pair entered the FOV of my camera, which I had aimed at Orion, Cygnus was no longer visible to the naked eye.

As a result, the image above (taken with an EF 2.0/35mm lens) is not the best: I had to pull a full suite of post-edit tricks to make the very faint trail of the Cygnus stand out a bit better. The image shows the pair traversing the area of Orion's belt and the Orion nebula.

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