Richard Branson due to take flight with Virgin Galactic Sunday

How to watch: Virgin Galactic will stream the launch live via its website starting at 9 a.m. ET.

• Khalid is expected to premiere a new song once the crew comes in for a landing, and Stephen Colbert is set to host the livestream.

How it works: Branson will fly with three other passengers and two pilots.

• The system works by using a carrier aircraft to loft the space plane — named Unity — to altitude. From there, the plane drops and its rocket engine kicks on, propelling the crew about 50 miles above the Earth's surface.
• Once at the top of the ride, the crew will feel weightlessness, floating through the cabin before strapping back in and gliding back down for a landing.
• Unlike an orbital launch — which can send a spacecraft around the Earth for days, weeks or even years — this suborbital flight will only last a matter of minutes.

The intrigue: If this mission launches as scheduled, Branson will beat fellow space billionaire Jeff Bezos to the punch.

• Bezos announced in June that he would fly aboard Blue Origin's first human flight of its suborbital New Shepard system on July 20.
• Not long after that announcement, Virgin Galactic announced that Branson would leapfrog Bezos, flying about a week before him.
• The two companies are now involved in a public rivalry, with Blue Origin posting an infographic on Twitter Friday comparing what it sees as the benefits to its system versus the drawbacks of Virgin Galactic's.

What to watch: After this launch, Virgin Galactic is expected to stage two more test flights before entering into full commercial operations in 2022.