In an official statement on Friday, acting NASA administrator Robert Lightfoot announced that NASA does not intend to fly a crew in the inaugural launch of their next generation rocket slated to take Americans to the moon and Mars, the Space Launch System (SLS).

While the plan had always called for an unmanned mission to be the first outing for the SLS and accompanying Orion spacecraft, President Trump’s NASA transition team encouraged them to reconsider.  As a result, NASA teamed up with the primary manufacturer of the Orion, Lockheed Martin, to conduct a feasibility study regarding adding a crew to the SLS’s first mission.

According to Lightfoot, the results of the study indicated that it was “technologically feasible” to add humans to the mission, but ultimately the decision was made not to do so.  By omitting the crew, Lightfoot explained, NASA can push the Orion’s propulsion systems harder and longer than they’d be willing to with astronaut’s lives at stake.  The first mission of the SLS will place it in orbit around the moon before returning to earth after an estimated 21 to 25 days.

This can be seen as the second bit of disappointing news regarding the SLS and Orion spacecraft to come out of NASA in recent months.  At the end of April, NASA officials announced that the first SLS launch would have to be pushed back from 2018 to 2019 “at the earliest.”  That announcement marked yet another delay, as the first launch was originally slated for 2016.  The reason for the latest set of delays was explained to be “structural weaknesses” in the rocket’s core stage.