NASA and Lockheed Martin Space Systems have finished testing the avionics system on the first flight version of the agency’s Orion crew capsule, the company announced April 7. 

The prototype Orion is set to launch in December, without a crew, aboard a United Launch Alliance Delta 4 Heavy rocket from Cape Canaveral Air Force Station in Florida. The stripped-down craft will orbit Earth twice, then plunge back into the atmosphere at speeds approaching those it would reach during a return from lunar orbit. The main objective — the craft will not be equipped with systems such as life support and solar arrays — is to test Orion’s heat shield.

“After powering on and sending commands to more than 20 different critical systems installed on the spacecraft’s crew module, NASA and Lockheed Martin engineers have verified the avionics for Exploration Flight Test-1 (EFT-1) are ready to support a successful flight and re-entry of the spacecraft,” Denver-based Lockheed Martin said in a press release. 

The tests took place at the Operations and Checkout facility at NASA’s Kennedy Space Center in Florida. Testing was briefly halted back in October because of the partial U.S. government shutdown, just as Lockheed and NASA were preparing to power up Orion for the first time. 

More recently, an interagency launch-scheduling board that includes NASA and the U.S. Air Force decided Orion’s maiden flight would be pushed back from September to December. The change was made to allow two military satellites, GPS 2F-6 and Air Force Space Command-4, to launch sooner than previously scheduled.

Lockheed Martin’s $11.76 billion Orion prime contract runs through 2020. NASA had spent $7.15 billion on the contract as of early March. 

NASA plans to use Orion, along with the Space Launch System heavy-lift rocket also in development, to send astronauts to a captured asteroid by 2025. NASA began studying the feasibility of that mission in 2013, but has yet to officially commit to it.