From the D23 Expo 2018 in Japan:

Quote Originally Posted by Disney Parks & Resorts

... With the “Guardians of the Galaxy”-inspired coaster, we’re going big. This one-of-a-kind family attraction will be one of the world’s longest enclosed roller coasters when it’s added to Future World at Epcot. It’ll feature a unique story currently being created by Walt Disney Imagineering and include a new innovative ride system that’s guaranteed to “wow” guests.

The “Guardians of the Galaxy”-inspired coaster is part of our ongoing work to transform Epcot into a place that’s more family, more relevant, more timeless and more Disney. “As we build upon its core mission of optimism and hope to inspire the world, the real will become fantastic and the fantastic will become real—in whole new ways at Epcot,” Bob Chapek, Chairman of Walt Disney Parks & Resorts, said.

The attraction will open in time for the 50th anniversary of Walt Disney World Resort in 2021.