2004: Finished Naysmyth telescope (supplied by DLR) mated into the modified aircraft and tested.

2006, April: All major structural modifications to the aircraft completed.

2007, April: First test flights of the Observatory.

2008, January: Closed door testing completed.

2008, June: First coating of primary mirror.

2008, June: Call for white papers for "Short Science" participation.

2008, September: Coated primary mirror delivered to Dryden Aircraft Operations Facility (DAOF).

2008, October: Short Science white papers reviewed, and selections announced.

2009, February: First open door flights; FORCAST integration and checkout.

2009, April: GREAT integration and checkout.

2009, April: Call for proposals for "Basic Science".

2009, June: Deadline for Basic Science proposal submission.

2009, May: Short Science observations with FORCAST begin.

2009, June: Short Science observations with GREAT begin.

2009, August: Basic Science proposal review.

2009, December: Basic Science observations begin.

2010, March: Call for "Observatory Characterization and Demonstration Science" (OCDS) proposals.

2010, December: OCDS observations begin.

2010: Call for proposals for new instruments.

2011, January: First General Investigator (GI) call for proposals (Cycle 0).

2011, October: Cycle 0 observations begin.

2011: "Limited Operational Capability" flights begin.

2014: "Full Operational Capability" flights begin.