Playing with a team mate this evening I discovered a couple of problems.....
1) You cannot enter the system together
2) It seems to scale as if there are 2 of you anyway
Earlier in the day I found that some of the missions require things like Medical Supplies or Provisions which are no longer found in the Replicator. These missions cannot be finished as once you go and get the supplies you cannot return to the system to need to help.
The problems exploring in a team are here since early Open Beta, maybe even Close Beta. Report the bug again. As for the scaling, actually I think it's a feature : as long as you're in a team, the missions scale even if your partners aren't with you right now.
Comments
Now to the bottom right you should see a blue tab that says "Continue mission in System blahblahblah"
Click on it and...
Voila.
The top issue is something i agree with, exploration missions should take your team all together to the same instance.