SpaceX's first uncrewed test flight of its Dragon capsule for astronauts has slipped to no earlier than January 2019 on account of the International Space Station's docking schedule, NASA announced today (Oct. 4).

The company and space agency are still planning to have all systems prepared for launch in December, a target date that NASA and SpaceX previously announced in August.

"Having completed a number of additional milestones including substantial training and numerous integrated mission simulations, end-to-end Dragon checkouts at the Cape, complete Falcon 9 vehicle integration review, and installation of the crew access arm at LC-39A, SpaceX is on track for launch readiness in December," SpaceX spokesperson Eva Behrend wrote in a statement to Space.com. "We look forward to launching our first demonstration flight of Crew Dragon — one of the safest, most advanced human spaceflight systems ever built — as part of the Commercial Crew program and working with NASA to identify the specific launch target date soon."

The NASA announcement comes just a day after Hans Koenigsmann, SpaceX's vice president of build and flight reliability, expressed concern that paperwork and scheduling issues could push the test flight into the next year, according to SpaceNews.

"The hardware might be ready, but we might still have to do some paperwork on the certification side of it," SpaceNews quoted Koenigsmann as saying Wednesday (Oct. 3) in a speech at the 69th International Astronautical Congress in Bremen, Germany. "It’s going to be a close call whether we fly this year or not."

NASA's update, which you can read here, also included the promise of more regular announcements of changes to the test launch schedule as those dates approach. SpaceX's competitor, Boeing, is currently working toward an uncrewed test flight in March 2019, according to the current plan.

Each of these two first-quarter test flights will see an empty capsule launch, dock with the space station, then detach and return to Earth as proof that the systems are ready for human crewmembers.

The uncrewed test flights are preparation for crewed test flights. According to the update, SpaceX's crewed test is currently scheduled for June 2019 and Boeing's for August 2019. NASA announced the crewmembers who would be aboard each flight on Aug. 3 of this year, with two astronauts slated for the SpaceX demo mission and three for Boeing's equivalent.

According to the NASA statement, the agency plans to update the schedule on a monthly basis now that the launches are approaching. "As we get closer to launching human spacecraft from the U.S., we can be more precise in our schedules," Phil McAlister, director of Commercial Spaceflight Development at NASA, said in the statement. "This allows our technical teams to work efficiently toward the most up-to-date schedules, while allowing us to provide regular updates publicly on the progress of our commercial crew partners."

Editor's note: This story has been updated to include a comment from SpaceX.

Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.