Space Exploration Technologies Corp. (SpaceX) powered up its second Dragon space capsule for the first time June 19, performing a round of checks on the spacecraft’s sensors and electrical and avionics systems.

“Last weekend, we powered up the spacecraft’s avionics for the first time after their installation in the vehicle,” SpaceX spokeswoman Kirstin Brost Grantham told Space News in a June 23 email. “This first power-up verified connectivity between the Dragon spacecraft and its ground support equipment, and marked the start of integrated spacecraft systems checkout activities.”

SpaceX in 2006 agreed to fly three Commercial Orbital Transportation Services (COTS) demonstration missions to prove to NASA that its Dragon cargo capsule and Falcon 9 medium-lift rocket are space-worthy.

SpaceX flew its first COTS demo flight in December, when it successfully launched its first Dragon capsule atop a Falcon 9 rocket. The spacecraft made two Earth orbits before splashing down into the Pacific Ocean, where it was recovered by the company.

Of the two remaining COTS flights, the first would entail sending a Dragon to within 10 kilometers of the international space station for a test of its guidance and communication systems. The next flight would require the Dragon to dock with the space station.

SpaceX wants to accomplish both of those objectives  in a single flight. NASA has not formally approved this plan, but the space agency has supported SpaceX in its efforts.

Earlier this year, NASA gave the company $128 million to conduct previously unscheduled ground tests that must be finished before the agency can clear the Falcon 9 and the Dragon to fly the combined flight.

Besides the capsule that flew to orbit in December, SpaceX currently has three Dragons, in varying stages of assembly.