Updated 1530CEST 4 June 2013
The flight control team at the joint ESA/CNES ATV Control Centre will assume control of the mission once Albert Einstein separates from the final stage of the Ariane 5 launcher on 5 June. From that point on, it will be in free-flight orbit under ATV-CC control until Rendezvous with the ISS, set for 15 June.
Below, you can access the (estimated) TLE – the ‘Two-Line Element’ data – that describes the orbit ATV is expected to be on once separation occurs.
This can be used by amateur astronomers, astro-photographers and anyone else to know where to look if you wish to spot ATV in the sky!
Ed: A little later, we’ll also publish a full description of where and when to look to spot ATV for anyone not used to working with TLE data.
First contact with ATV (‘AOS’ – acquisition of signal) is expected to happen about 00:56 CEST on 6 June, some 30 seconds after ATV’s separation from the Ariane 5 upper stage (contact will be made via NASA’s TDRSS data relay satellite system). Once mission controllers at ATV-CC has contact with ATV, the flight dynamics team will perform an orbit determination to ‘fix’ the precise trajectory that Albert is following around Earth.
In the meantime, ESA’s Laurent Arzel, one of the flight dynamics experts at ATV-CC, has sent in the forecast TLE – the standard ‘Two-Line Element’ data that describes the orbit of any object – describing the orbit that the vessel is expected to be on once separation occurs (the actual orbit will vary a bit from this estimate, but for backyard astronomers keen to spot ATV in the sky, this should be sufficiently accurate).
Laurent has provided the estimated orbital parameters for each day of free-flight orbit up to Rendezvous with the ISS on docking day, set for 15 June.
If you’re on the ground with a clear night sky, you can plan to look up and spot ATV based on these data.
We’ll also post a graphical map here in the blog to show you where ATV is in real time, starting with launch day.
ATV-4 TLE (Estimated – update as of 15:30 CEST 5 June 2013) 6-15 June 2013