Despite more storms in the forecast, SpaceX pressed ahead Saturday in its historic attempt to launch astronauts for NASA, a first by a private company.

Forecasters put the odds of acceptable conditions at 50-50 for the 3:22 p.m. liftoff of a SpaceX Falcon 9 rocket — the first launch from the U.S. with NASA astronauts in nearly a decade.

SpaceX and NASA managers monitored the weather not just at Kennedy Space Center, but all the way up the Eastern Seaboard and across the North Atlantic to Ireland. Waves and wind needed to be within limits in case the SpaceX Dragon crew capsule, carrying Doug Hurley and Bob Behnken, needed to make an emergency splashdown on the way to orbit.

A man sets up his camp along the Indian River Lagoon at sunrise Saturday, May 30, 2020, at Titusville, Fla. as he waits to watch the launch of the SpaceX Falcon 9, with Dragon crew capsule on top of the rocket. Two astronauts are set to fly on the SpaceX Demo-2 mission to the International Space Station scheduled for launch from the Kennedy Space Center in Cape Canaveral, Fla. For the first time in nearly a decade, astronauts will blast into orbit aboard an American rocket from American soil, a first for a private company. (AP PhotoCharlie Riedel)

A man sets up his camp along the Indian River Lagoon at sunrise Saturday, May 30, 2020, at Titusville, Fla. as he waits to watch the launch of the SpaceX Falcon 9, with Dragon crew capsule on top of the rocket. Two astronauts are set to fly on the SpaceX Demo-2 mission to the International Space Station scheduled for launch from the Kennedy Space Center in Cape Canaveral, Fla. For the first time in nearly a decade, astronauts will blast into orbit aboard an American rocket from American soil, a first for a private company. (AP PhotoCharlie Riedel)

Their destination is the International Space Station, a 19-hour flight away.

"We are moving forward with launch today. Weather challenges remain with a 50% chance of cancellation," NASA Administrator Bridenstine tweeted.

Wednesday's countdown was halted at just under 17 minutes because of the threat of lightning. “Falcon/Dragon are designed to withstand multiple lightning strikes, but we don’t think it would be wise to take this risk,” tweeted Elon Musk, SpaceX's chief executive and founder.

A man fishes in the Indian River Lagoon at sunrise Saturday, May 30, 2020, at Titusville, Fla. as he waits for the launch of the SpaceX Falcon 9, with Dragon crew capsule on top of the rocket. Two astronauts are set to fly on the SpaceX Demo-2 mission to the International Space Station scheduled for launch from the Kennedy Space Center in Cape Canaveral, Fla. For the first time in nearly a decade, astronauts will blast into orbit aboard an American rocket from American soil, a first for a private company. (AP PhotoCharlie Riedel)

A man fishes in the Indian River Lagoon at sunrise Saturday, May 30, 2020, at Titusville, Fla. as he waits for the launch of the SpaceX Falcon 9, with Dragon crew capsule on top of the rocket. Two astronauts are set to fly on the SpaceX Demo-2 mission to the International Space Station scheduled for launch from the Kennedy Space Center in Cape Canaveral, Fla. For the first time in nearly a decade, astronauts will blast into orbit aboard an American rocket from American soil, a first for a private company. (AP PhotoCharlie Riedel)

Hurley and Behnken noted Friday that they endured numerous delays on their space shuttle flights, for both technical and weather reason. Hurley said his first mission was postponed five times over the course of a month. His second mission was NASA's final space shuttle flight in July 2011, the last time astronauts rocketed away from home soil.

President Donald Trump and Vice President Mike Pence planned to return for the second launch attempt. And early Saturday morning, spectators began lining the Banana and Indian rivers in surrounding towns for front-row views. Signs along the main drag along the beaches urged “Godspeed.”

NASA had discouraged spectators because of the coronavirus pandemic, and extremely limited the number of employees, visitors and journalists inside Kennedy Space Center.

This combination of undated photos made available by SpaceX shows NASA astronauts Doug Hurley, left, and Bob Behnken in their spacesuits at SpaceX headquarters in Hawthorne, Calif. On Wednesday, May 27, 2020, They are scheduled to board a SpaceX Dragon capsule atop a SpaceX Falcon 9 rocket and, equipment and weather permitting, shoot into space. It will be the first astronaut launch from NASA’s Kennedy Space Center since the last shuttle flight in 2011. (SpaceX via AP)

This combination of undated photos made available by SpaceX shows NASA astronauts Doug Hurley, left, and Bob Behnken in their spacesuits at SpaceX headquarters in Hawthorne, Calif. On Wednesday, May 27, 2020, They are scheduled to board a SpaceX Dragon capsule atop a SpaceX Falcon 9 rocket and, equipment and weather permitting, shoot into space. It will be the first astronaut launch from NASA’s Kennedy Space Center since the last shuttle flight in 2011. (SpaceX via AP)

NASA hired SpaceX and Boeing in 2014 to taxi astronauts to and from the space station, under contracts totaling $7 billion. Both companies launched their crew capsules last year with test dummies. SpaceX's Dragon aced all of its objectives, while Boeing's Starliner capsule ended up in the wrong orbit and almost was destroyed because of multiple software errors. As a result, the first Starliner flight carrying astronauts isn't expected until next year.

NASA wants to ease its reliance on the Russian Space Agency, the only route for crews to the space station since the retirement of the space shuttles. It's cost NASA billions of dollars for Russian Soyuz seats.

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