New York CNN Business  — 

NASA has two new dates in mind — September 23 or September 27 — for the next attempt at launching its massive new moon rocket on an uncrewed test mission. But there are still several things that could stand in the way of getting the Artemis I mission off the ground, any of which could push the launch date back further.

The crew climbed aboard their SpaceX Crew Dragon capsule after midnight and detached from the space station in the early hours of Thursday morning. They’ll spend all day Thursday free flying through orbit as their spacecraft maneuvers closer to the edge of the Earth’s atmosphere.

The four astronauts on the Crew-3 mission are NASA’s Raja Chari, Tom Marshburn, and Kayla Barron, as well a German astronaut with the ESA, Matthias Maurer.

After the capsule made a safe landing, bobbing up and down in the Gulf of Mexico off the coast of Florida, Chari told mission control: “Thanks for letting us take [Crew Dragon] Endurance on a shakedown cruise.”

“Looking forward to watching many more flights of Endurance in the future,” he said, using the “Endurance” name bestowed on Crew-3’s capsule. “That was a great ride. Enjoyed working with the NASA and SpaceX team. Thanks for getting us to the space station and back safely.”

This will mark the conclusion of SpaceX’s third operational mission to the ISS that the company has conducted in partnership with NASA.

SpaceX has had a whirlwind month of activity. It kicked off with the launch of the private AX-1 mission to the ISS on April 8, and the company brought that crew home just last week. Then SpaceX launched the Crew-4 astronauts, who will replace the Crew-3 astronauts on the ISS staff, last Wednesday, then immediately began gearing up for Crew-3’s return. Meanwhile, the company’s Falcon 9 rocket has kept busy launching satellites to orbit, which includes a batch of the company’s Starlink internet satellites, just last Friday.

Falcon 9 rockets have already notched 17 launches so far this year.

The intent of SpaceX’s Crew Dragon program was to return astronaut launches to the United States for the first time since NASA’s Space Shuttle program retired in 2011, allowing NASA to keep the space station fully staffed with its own astronauts as well as astronauts from partner space agencies such as the European Space Agency (ESA). Before the Crew Dragon entered service in 2020, NASA was forced to rely on Russian Soyuz spacecraft for ISS crew transportation.