Lockheed Martin Space Systems said its Orion deep-space crew capsule made it through vibration testing at the Kennedy Space Center in Florida, bringing the spacecraft one step closer to its uncrewed debut flight in December. 

Lockheed said in an April 29 press release that the capsule’s next vibration test will be carried out with its service module attached. Orion, with its service module, is slated to launch aboard a United Launch Alliance Delta 4 rocket in December. The mission, dubbed Exploration Flight Test-1, is intended to stress test Orion’s heat shields during a high-velocity atmospheric re-entry. 

Orion’s first flight aboard NASA’s heavy-lift Space Launch System rocket is slated for 2017. In that uncrewed mission, Orion will fly a round trip to the same distant lunar retrograde orbit into which NASA is considering corralling a small asteroid that would be visited as soon as 2025 by a future Orion crew.

Lockheed Martin’s nearly $12 billion Orion prime contract runs through 2020.