While Iron Man is one of the most popular movies in the Marvel Cinematic Universe, with three adventures and over $1 billion in ticket sales, the future of Tony Stark is uncertain. We know we'll next see Robert Downey Jr. reprising the role he made famous in Avengers: Age of Ultron. And he has commited to The Avengers 3. But after that, Marvel hasn't offered any details. Now, a new survey sent out by Marvel Studios over the weekend during NYC screenings of Captain America: The Winter Soldier suggest we may be seeing Iron Man 4 sooner than later.

The sequel is certainly on the minds of those at Marvel. This portion of the survey asks fans which Marvel movie are they most interested in seeing next, and it includes Avengers: Age of Ultron, Ant-Man, Iron Man 4, Thor 3 and Captain America 3. Not included are Guardians of the Galaxy and suspected Phase Three movie Doctor Strange, which has been hinted at but not yet confirmed as part of the line-up.

Where Iron Man 4 winds up is an interesting question. An even more interesting question is, will Robert Downey Jr. return to play Tony Stark in another stand-alone sequel? The actor himself has said he will retire the character after returning for The Avengers 3, which will rap up Marvel Phase Three, a slate confirmed to include Ant-Man and Captain America 3. Right now, its presumed that Phase Three will include 5 movies total, and while Thor 3 hasn't been given the official greenlight, Marvel has already set up a writing staff with Craig Kyle (producer on Thor and Thor: The Dark World) and Christopher Yost (one of the writers on Thor: The Dark World). That leaves one other film, and all signs point to it being Doctor Strange, as Marvel looks to establish another new franchise along with its returning favorites.

This can only mean that Iron Man 4, if it were to happen, will be part of the Phase Four line-up. Robert Downey Jr. had this to say about retiring from the character:

"It got me thinking about how big the message from your cosmic sponsor needs to be before you pick it up. How many genre movies can I do? How many follow-ups to a successful follow-up are actually fun? Because, as quiet as it's kept, I come from a family of very innovative writers and directors and actors and artists, and the circle of friends they were in were the people I heard having pun-offs playing poker at two in the morning, and it was just the most comforting aspect of my childhood. So there's this kind of legacy of souls from what I consider to be a very particular time in entertainment, and I'm sensing a return to that...it's what me and the missus are doing next. It's not unlike: I heard (Tom) Brady signed on for three more years with New England, and then he's done being a QB, because he'll be 40. I'm 47, and I'll be 50. don't know. Right now I don't have a contract to do anything, and I did for the last five years."

Marvel is not looking to reboot their Iron Man franchise. Instead, they plan to have a new actor come in and run with the already established storyline. As a trilogy, Tony Stark's story was wrapped up quite nicely with Iron Man 3, and many have wondered how it will continue in Avengers: Age of Ultron, with his participation in The Avengers 3 rumored to be limited as he passes the torch to new Avenger team members. There's always the possibility that Robert Downey Jr. will return, if the story is good enough. But we won't likely see it until 2019 or 2020, when audiences may be at a point where they are ready to accept a new face as Tony Stark.