It seems to be the Earth & Moon pieces at the top and bottom are going to be the shapes of shuttles passing each other when all the covers are placed side by side.
For reference, here’s the Collection 02 prelim cover.
Starts Friday, January 2, 2015, on the Anime Network Online Player
Language: Japanese w/ English Subtitles
Episodes 1-13 (Sub) are live at ANO
These episodes are now listed as FREE.
Is there any background info on this? Does it imply something?
Or, is it just anime bros being anime bros? 
Limited Edition “Space Brothers” Volume 25 comes with Pretty Dog Mirror
February 22, 2015 11:37pm CST
Latest volume of Chūya Koyama’s hit manga arrives at Japanese stores February 23, 2015
COLLECTION 2 COMING TO ANIME NETWORK MARCH 6, 2015
Language: Japanese w/English Subtitles
Just started watching this show, up to Ep. 3. I’m hoping I can push by my Episode limit for shows (You’re Under Arrest is my highest Episode watched show S1-3 Movie and mini-specials)
Conan is technically #2 @ Ep. 87 (but still have a long way to go to finish it up)
Episodes 14-26 (Sub) are live at ANO
These episodes are now listed as FREE
http://ask.fm/SentaiFilmworks/answer/126189406941
Q. Will you be releasing Space Brothers entirety? I see half of series is for sale but will 2nd half be in the future?
A. Yes, we definitely will. We are trying to release a new collection of episodes every other month, so eventually we will have the entire series available.
Space Brothers Collection 3 COMING TO THE ANIME NETWORK ONLINE PLAYER June 5, 2015
Languages: Japanese w/ English Subtitles
Episodes 27-38 (Sub) are live at ANO
These episodes are now listed as FREE.
They were always free.
Ahh.
Never noticed since I didn’t post it this time and you didn’t mention it in your post.