It could happen only in Roswell. City officials want to help build a UFO-themed amusement park, complete with an indoor roller coaster that would take passengers on a simulated alien abduction. he park could open as early as 2010. The city has received a $245,000 legislative appropriation for initial planning, but the park would be privately built and managed. Requests for proposals will be advertised next month. City Planner Zach Montgomery said the project will cost “several hundred millions of dollars,” but a more accurate figure hasn’t been determined. A roller coaster similar to the one proposed by Temmer is currently under construction at another theme park for almost $100 million, Montgomery said.