Richard Branson will finally get his space trip on Sunday.

It’s been a very long wait for Mr. Branson, the disrespectful 70-year-old British billionaire who runs a galaxy of Virgin businesses. In 2004, he founded Virgin Galactic to bring adventurous tourists to the edge of space and back in rocket-powered aircraft.

At the time, he thought the commercial service would begin in two to three years. Instead, almost 17 years have passed. Virgin Galactic says there are three more test flights to be done, including the one on Sunday, before it can be ready for paying passengers.

For this flight, Mr. Branson will be a member of the crew. Its job is to evaluate the cabin experience for future customers.

The flight is scheduled to take off on Sunday morning from Spaceport America in New Mexico, about 180 miles south of Albuquerque.

Virgin will air coverage of the flight from 9:00 a.m. Eastern Time, with Stephen Colbert hosting the live stream. Singer Khalid is due to sing a new song after the crew lands, and SpaceX founder Elon Musk suggested he could perform.

The rocket plane, a type called SpaceShipTwo, is about the size of an executive jet. In addition to the two pilots, there are four people in the cabin. This particular SpaceShipTwo is called VSS Unity.

To take off from the ground, Unity is brought to an altitude of approximately 50,000 feet by a larger aircraft. There Unity is released and the engine of the rocket plane is ignited. The acceleration will make people on board feel a force up to 3.5 times their normal weight as they travel to an altitude of more than 80 miles.

At the top of the arch, passengers can get up from their seats and experience apparent weightlessness for about four minutes. Of course, they won’t have escaped gravity. At fifty miles up the earth’s downward gravitational pull is essentially as strong as it is on the ground; rather, the passengers fall at the same speed as the aircraft around them.

The two tail booms at the rear of the spacecraft rotate into a “feathered” configuration that creates more drag and stability and allows the aircraft to enter the Earth’s atmosphere more gently. This configuration makes SpaceShipTwo more like a badminton shuttlecock, which always falls with the pointed side down, than an airplane.

Nevertheless, the forces that can be felt on the passengers when descending are greater than when ascending and reach six times the force of gravity.

Once the aircraft is back in the atmosphere, the tail booms rotate back down and the aircraft glides off for a landing. The entire flight can take less than two hours.

The pilots are David Mackay and Michael Masucci.

In addition to Mr. Branson, three Virgin Galactic employees will evaluate what the experience will be like for future paying customers. You are Beth Moses, the lead instructor for the astronauts; Colin Bennett, chief operations engineer; and Sirisha Bandla, vice president of government affairs and research operations. Ms. Bandla will also conduct a science experiment provided by the University of Florida.