A billionaire private spaceship flight - funded by businessman Jared Issacman - has filled its two remaining seats with a college teacher and a data engineer.
The charity mission will set off in a ‘dragon capsule’ owned by Elon Musk’s SpaceX company, which was set up in 2002 in California, in a bid to get astronauts on Mars by 2027.
Who are the four members in the all-civilian starship crew?
The latest team members were introduced at a news briefing live streamed from the Kennedy Space Center in Florida.
The crewmates are Sian Proctor, a community college teacher in Arizona, and Chris Sembroski, a former Air Force missileman from Washington.
Ms Proctor, 51, was born in Guam, where her late father worked at Nasa's tracking station for the Apollo moonshots.
She beat 200 businesses for an out-of-this-world experience after an independent panel of judges chose her space art website, Space2inspire.
"It was like when Harry Potter found out he was a wizard, a little bit of shock and awe," she said last week. "It's like, 'I'm the winner?'”
Mr Sembroski, 41, was not picked in the random draw earlier this month but his friend was instead.
His friend declined to fly for personal reasons and offered the spot to Mr Sembroski who worked as a Space Camp counsellor in college and volunteered for space advocacy groups.
"Just finding out that I'm going to space was an incredible, strange, surreal event," he said.
They are joining Hayley Arceneaux, 29, who was the first crewmate named.
She works at the same cancer research hospital the charity space flight is fundraising for.
The St Jude physician's assistant was treated there as a child for bone cancer.
Who is Jared Issacman?
Mr Isaacman is head of Shift4 Payments, a credit card-processing company in Pennsylvania.
He is paying for what would be SpaceX's first private flight while raising money for St Jude Children's Research Hospital in Memphis.
Mr Isaacman, 38, is also a pilot who will serve as the spacecraft commander.
He has not revealed how much he's paying for the flight but it is known that he is donating $100 million (£73 million) to St Jude as part of the charity mission.
Other donors so-far have contributed $13 million (£9.5 million), primarily through the lottery that offered a chance to fly in space.
When will the spaceship launch into orbit?
Their SpaceX Dragon capsule will launch no earlier than mid-September, aiming for an altitude of 335 miles.
That is 75 miles higher than the International Space Station and on a level with the Hubble Space Telescope.
The capsule will be fitted with a domed window in place of the usual space station docking mechanism for their trip.