.. How to get back to ascension station

It is just missing the label with the destination. Do you remember what it looked like from the beginning?

It looked a lot like those papers you've been painting with Middle Rufus.

Can you switch items with Left Rufus?

Great, now you can transfer the picture of Elysium from Middle Rufus to Right Rufus through Left Rufus.

Confusing. Anyways, Right Rufus should now have the picture. Go attach it to the barrel and hop in.

Talk to Oppenbot from the barrel.