NASA's Space Launch System and the Orion spacecraft need to complete tests flights before the EM1 mission in deep space. Manned test flights are also mandatory. However, NASA revealed that the maiden flight for both SLS and Orion will have no crew on board despite it being considered earlier.

Experts started looking into the possibility of putting a team of onboard the first integrated flight of NASA SLS and the Orion capsule for the Exploration Mission-1 (EM-1). However, after the assessment, NASA engineers agreed on pursuing the first integrated launch without a crew.

The first integrated flight will be a "rigorous" test flight, according to NASA. The data collected from the flight will be used to prepare the SLS rocket and the Orion capsule for future manned launches. This will help extend human presence deeper in the Solar System.

NASA first believed that the maiden integrated flight could house a team of astronauts. But it was recently scrapped due to increased risk and technical factors considered. NASA says it's a bit difficult to accommodate last minute changes with a project this big. It was decided than an unmanned EM-1 maiden flight is the best approach for the mission.

"We appreciate the opportunity to evaluate the possibility of this crewed flight," NASA acting Administrator Robert Lightfoot said in a press release. "The bi-partisan support of Congress and the President for our efforts to send astronauts deeper into the solar system than we have ever gone before is valued and does not go unnoticed. Presidential support for space has been strong."

The SLS is also called the most powerful rocket ever built. But without the capability to carry humans to deep space, it won't be much help in expanding the human presence in the Solar System. This is why the Orion capsule is vital to EM-1. Both SLS and Orion's integrated capabilities are important thus NASA is taking precautions in future testing to maximize their potential.

In the long run, deferring the manned integrated flight for SLS and Orion will give engineers more time to assess the system in order to secure a successful first manned integrated flight.