SpaceX has officially delayed the first flight of its Crew Dragon vehicle, which was originally planned to take NASA astronauts to and from the International Space Station in 2017.

The move comes after the Falcon 9 rocket explosion in September. According to a NASA blogpost, SpaceX is slated to launch the crewed flight in May 2018 after performing a demonstration mission of Crew Dragon in November 2017 without any crew.

According to The Verge, SpaceX has been working closely with NASA as a part of its investigation into the Falcon 9 rocket explosion and has finalized its results.

"We are carefully assessing our designs, systems, and processes taking into account the lessons learned and corrective actions identified. Our schedule reflects the additional time needed for this assessment and implementation," the company said.

NASA has been working hard with two private companies, SpaceX and Boeing, to build vehicles capable of carrying people to the ISS in lower Earth orbit. While SpaceX is updating its Dragon capsule (which has been used to transport supplies to the ISS), Boeing is making a new capsule called the CST-100 Starliner.

Like SpaceX, Boeing has also delayed its first crewed flight of Starliner twice and now intends to launch the mission in August 2018 for the first time.

NASA Administrator Charles Bolden partially blames Congress for not properly funding the Commercial Crew program. However the initiative received the president's full support.

Currently, NASA depends on Russian Soyuz rocket, the only vehicle capable of taking humans to the ISS. One seat on the Soyuz reportedly costs NASA roughly $81 million.

In related news, the Soyuz experienced a failure during an uncrewed mission to the ISS last week.