While SpaceX is developing the Falcon Heavy rocket, scheduled for a first test launch in December, NASA is working on its own rocket for deep space exploration called the Space Launch System rocket accompanied by the Orion spacecraft. The two companies are working on the massive rockets in the hopes of launching humans deeper to space than any rocket has ever before, possibly even to Mars.

NASA has completed its first review of the launch schedule for the SLS and has updated the plans and timeline for the first integrated launch accordingly. After the review NASA decided to plan for a December 2019 launch although sometime in 2020 is probably more likely, according to a release from NASA.

That first launch will be an unmanned mission and is currently named Exploration Mission-1, or EM-1, for now. The unmanned mission will be the true test for the SLS and the Orion craft before NASA puts humans on board. The Orion craft will launch on top of the SLS and then return to Earth after bringing passengers to their deep space or planetary destinations. The craft has three parts, the top abort section for emergencies, the middle section serves as the crew module and the bottom part is the service module. NASA had previously already decided to fly the first mission with no passengers but doubled down on the decision after further evaluation and testing was done. 

The hopeful timeline comes thanks to potential problems that NASA was able to prepare for, but did not suffer when working on the creation of the SLS thus far. Additionally, most of the work for the SLS is on track, NASA said in a release. New production milestones were put in place by NASA to avoid potential malfunctions. Not only is the work being completed on time, it’s also on budget as of the November review.

Last month NASA tested the RS-25 flight engine E2063 that is set to be used for the SLS. The engine is one of four that the SLS will require and will help provide the 2 million pounds of thrust that will help get the SLS and its payload to space.

Now new plans to test the launch abort system are also in the works. That test is currently targeted for April 2019 and will show how well the system can get the eventual crew to safety during the future launches. The first launch for a flight involving a crew isn’t schedule until 2023 however, so there’s still plenty of time for NASA to test these systems.

NASA released a video on Wednesday that shows the rocket as well as the craft and the safety testing it is undergoing to test whether astronauts will easily be able to escape the Orion craft as well as for the ground crew to be able to escape the area around the SLS if necessary.