When was the science fiction museum build?

There is no single "Science Fiction Museum" that everyone agrees on. You may be thinking of one of these:

* The Museum of Science Fiction (MoSF) in Washington, D.C. was founded in 2005 and opened to the public in 2016.

* The Science Fiction Museum and Hall of Fame in Seattle, Washington, was founded in 1999. It was originally located in Seattle Center and closed in 2004. The museum is currently closed and there are no plans to reopen it.

* The Science Fiction Museum of France in Paris was founded in 1994.

Please clarify which museum you are asking about, and I can give you a more precise answer.