Four astronauts blasted off in SpaceX's Falcon rocket on Sunday as they headed to the International Space Station, where they will oversee the arrivals of two new rocketships during their six-month stint.

The rocket launched from Kennedy Space Center in Florida with NASA's Matthew Dominick, Michael Barratt and Jeanette Epps and Russia's Alexander Grebenkin on board.

The astronauts are expected to reach the orbiting lab on Tuesday and will replace a crew from the U.S., Denmark, Japan and Russia, who have been there since August.

The launch came after three days of delays due to high winds. SpaceX Launch Control described it as "fashionably late."

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Another delay almost happened again Sunday night after a small crack in the seal of the SpaceX capsule's hatch led to several last-minute reviews, but it was ultimately deemed safe for the whole mission.

The new crew's six-month stay includes the arrival of two rocketships ordered by NASA. Boeing’s new Starliner capsule with test pilots is expected in late April and Sierra Space's Dream Chaser, a mini-shuttle, should arrive a month or two later.

Astronaut Epps was originally assigned to fly Boeing’s Starliner, which sustained problems and stalled. NASA later moved her to SpaceX.

She is an engineer, having worked for Ford Motor Company and the CIA before becoming an astronaut in 2009. Epps was initially scheduled to launch to the space station on a Russian rocket in 2018 but was replaced for reasons that were never publicly disclosed.

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Dominick, a Navy pilot, and Grebenkin, a former Russian military officer, are also new to space, while Barratt, a 64-year-old doctor on his third mission, is the oldest full-time astronaut to fly in space.

"It's kind of like a roller coaster ride with a bunch of really excited teenagers," Barratt said after reaching orbit. 

Speaking about his age before the flight, Barratt said, "As long as we stay healthy and fit and engaged, we’re good to fly."

Flight controllers are monitoring a growing cabin leak on Russia's side of the space station. The leak has doubled in size in the past few weeks and the area has been sealed off, according to NASA program manager Joel Montalbano, who emphasized that there is no impact on station operations or crew safety.

The Associated Press contributed to this report.