I would like to know the meaning of a sentence below:
"While docked, the ATV will perform ISS attitude control, debris avoidance manoeuvres and raising of the 183 tonne station's orbit to overcome the effects of atmospheric drag."
I cannot understand "raising of the 183 tonne station's orbit...". The weight of ISS is not 183 tonne, right? What does this "183 tonne" refer to?