A historic spacecraft flight is expected to cross Irish skies just before 10pm tonight, 20 minutes after it blasts off from Florida.
Elon Musk's SpaceX is preparing to become the first private spaceflight company to launch NASA astronauts into orbit, with plans to eventually send humans to Mars.
Nasa and SpaceX are on course to make history as they launch two astronauts into space from US soil for the first time since 2011.
Robert Behnken and Douglas Hurley will journey to the International Space Station (ISS) at around 9.30pm Irish time on May 27.
It will also be the first time a private company has attempted to send astronauts into space.
Astronomy Ireland expects we will see the craft cross Ireland, just below the moon, at 9.53pm tonight.
The mission, known as Demo-2, will allow the US to once again send humans into space.
According to Nasa, this is a demonstration mission to show SpaceX’s ability to ferry astronauts to the space station and back safely.
It is the final major step required by SpaceX’s astronaut carrier, the Crew Dragon, to get certified by Nasa’s Commercial Crew Programme for more long-term manned missions to space.
SpaceX’s Falcon 9 rocket will take off from the launchpad 39A at the Kennedy Space Centre in Florida, carrying the Crew Dragon spacecraft where Mr Behnken, 49, and Mr Hurley, 53, will be seated.
Mr Behnken will serve as the mission’s joint operations commander and take responsibility for the rendezvous, docking and undocking of the Dragon capsule, while Mr Hurley will be in charge of the launch, landing and recovery of the vehicle in his role as the Crew Dragon spacecraft commander.
The Demo-2 mission is expected to last anything between one and four months. But Nasa said the duration of this mission would be determined by when the next commercial crew will be able to travel to the space station.
The spacecraft will be capable of staying in orbit for at least 210 days.
When it is time to return, the Crew Dragon will autonomously undock with Mr Behnken and Mr Hurley on board and depart the space station.
Shortly after firing up its engines to re-enter the Earth’s atmosphere, the spacecraft will deploy four parachutes to slow its descent and splash down in the Atlantic Ocean, just off the coast of Florida.
SpaceX’s recovery ship, called Go Navigator, will be waiting nearby to retrieve the duo and ferry them to Cape Canaveral.