Watch Live As SpaceX And NASA Launch Two Astronauts To The ISS Today

Today, Wednesday, May 27 at 4.33 pm EDT two NASA astronauts might fly to the International Space Station (ISS) onboard a private spacecraft in a historic launch from Florida's Kennedy Space Center. This is the first crewed launch for NASA's Commercial Crew Program, and is also the first crewed launch from American soil since the Space Shuttle Atlantis was retired in 2011.

The launch will only go ahead if strict weather criteria are met. Over the last few days, the weather has not been looking great – strong winds, and a tropical storm forming off South Carolina. The weather conditions currently are giving a 50/50 chance of it happening, down from 60 percent yesterday, according to the US Air Force 45th Weather Squadron. The final decision if the launch is "go" will happen 45 minutes before launch. If it ends up being postponed the next launch window is the weekend. 

The rocket and capsule have been developed by Elon Musk's company SpaceX, the first time a private company has built the vehicle that will take astronauts to space. Weather permitting, the launch will see experienced NASA astronauts Robert Behnken and Douglas Hurley fly the brand-new Crew Dragon capsule from the Kennedy Space Center to the ISS, a journey that takes just over 19 hours. Once docked, the two astronauts will join the members of Expedition 63 for as little as a month or up to four.

Behnken and Hurley are both veterans of the Space Shuttle program and this launch, which is codenamed Demo-2, is their third foray into space. Demo-1 was the capsule's first launch in 2019 where, uncrewed, it delivered equipment and supplies to the ISS. The capsule and the two astronauts are expected to return to Earth no later than the last week of September, with a splashdown in the Atlantic ocean.

Currently, all astronauts are flown to the ISS on Russia's Soyuz capsule, at a cost of $80 million per seat. NASA's Commerical Crew Program is an initiative developed to utilize rockets designed by private space companies, allowing the agency to provide more resources and attention to deep-space missions like returning to the Moon, and later, Mars. 

The launch of the Commercial Crew Program is certainly a milestone moment, for better or worse, as it marks a clear shift in how human access to space is performed in the United States. The road to get here was not easy, marked by delays and safety concerns. It's taken SpaceX six years and three failed launches, while Boeing’s own launch is expected to take place at some point next year. Assuming it goes ahead successfully, a new era of spaceflight just opened up.

You can watch this historic launch on NASA's TV channel and social media channels – the full list of how and where to stream is here – or you can watch it right here below.