A diameter of just 40 to 100 meters*
Will start counting the days until Trump announces that Musk will send Starship up to collect the entire thing[1] and bring it back to to get one over on China.
[1] yes, I know, even at best this is out by a factor of around 25 to 30 (depending upon how well it is packed) to fit into the payload bay, but perhaps just give it a shove in our direction?
* insert obligatory "gas or electric?" here.
PS
In all seriousness, good to see more science missions, even if there are sneaking suspicions this may(!) have some political motivations.