A decade-long journey to the launch pad could end on Tuesday for SpaceX’s Falcon Heavy rocket with the long-awaited maiden launch of the tri-core rocket. With a commercial launch license from the FAA in hand, a clean Launch Readiness Review and fair weather forecast, SpaceX wheeled the monster rocket up the ramp to Launch Complex 39A at the Kennedy Space Center Sunday night and placed it in its vertical launch position for liftoff on Tuesday during a two-and-a-half-hour window opening at 18:30 UTC, 1:30 p.m. local time.

SpaceX’s tri-core Falcon Heavy rocket breathed fire for the first time on Wednesday atop its Kennedy Space Center Launch Pad, igniting all 27 Merlin engines on the rocket’s business end for a 12-second test firing designed to collect valuable data not only on the behavior of the engines but also the rocket’s structure as a whole.