Space Exploration Technologies (SpaceX) plans to load “late cargo” into its Dragon capsule around April 20 after passing NASA’s final flight readiness review in advance of the first private space mission expected to dock with the International Space Station (ISS).

Speaking at the National Space Symposium here, SpaceX President Gwynne Shotwell says all but a handful of final items have been completed for the Johnson Space Center review, but that the Falcon 9 and its Dragon capsule have been given the green light for launch. A final static firing on the launch pad is scheduled before the planned mission on April 30. “If we don’t do April 30, we have another opportunity on May 3,” she says.

The initial mission is a proving flight and will not deliver a payload to the ISS, but the Dragon will be carrying dummy cargo to represent mass. Following launch, the Dragon is scheduled to take around four days to dock with the space station, and will remain attached to it for 18 days. In the run-up to docking, the spacecraft is expected to perform a series of preplanned maneuvers to demonstrate its agility, communications and navigation capabilities.

SpaceX notes that sites in Hawaii and Puerto Rico are also in the running for a possible base for Falcon 9 and Falcon Heavy operations. The company, which also is looking at sites in Florida, recently confirmed that FAA is preparing an environmental impact statement for a SpaceX commercial launch complex in Brownsville, Texas (Aerospace DAILY, April 11). FAA’s Office of Commercial Space Transportation plans a May 15 presentation and hearing in Brownsville as part of the scoping process.

SpaceX envisions up to a dozen launches annually of the medium-lift Falcon 9 and larger Falcon Heavy, as well as a range of suborbital missions using a Falcon 9 core-stage vehicle. The company had listed California, Florida, Virginia and Alaska locations as prospects.

The hunt comes as SpaceX continues work on setting up the SLC-4 launch site at Vandenberg AFB, Calif., for its first West Coast Falcon launch. The launch vehicle will “hopefully be vertical at Vandenberg later this year or early next, and be ready for launch in 2013,” Shotwell says.