I think season 4, so far, is way better than season 3. I was immensely disappointed with season 3 though so I don't know if that is saying much lol. I do not believe that anyone will go back up to space, personally. I can think of a few different scenarios that could possibly happen. Either they find the 4% (or whatever tiny amount it was) that will not be affected by the radiation or they go underground or into the sea (under the sea?), or they find a way to immune themselves against the radiation with Luna's blood somehow since in the last episode it showed she got better from the poisoning.

I'm not sure how they can make themselves immune to that fire storm that killed the woman in Egypt.

I don't know why, but I always thought this was going to end with Clark's death, sacrificing herself for the others to live.

I dont think they can make them selves immune from the fire storm, but they can make themselves immune for the after radiation and just hide below ground for a while.... possibly, or avoid it, if they are immune from radiation they could prolly drink from lakes and things,

Yeah, Xsploit's response is exactly what I was thinking. As long as they can make themselves immune from the radiation, they should have no problem hiding out underground for a little while. I don't think Clark is going to die, personally, but I have been shocked by sudden deaths on this show before lol.

clarke is main character, she isnt going to die any time soon

It's interesting to read all these predictions after watching the finale. It looks like the writers chose just about every one of them. Some escaped back to space, some underground and some nightbloods on the surface after the storm died down. I guess they remembered not to keep all your eggs in one basket.