Blue Origin’s New Glenn rocket is poised upright at Launch Complex 36 at Cape Canaveral Space Force Station in Florida.
Preparations began in earnest several hours before launch when liquid hydrogen started flowing into New Glenn’s propellant tanks.
At 10 minutes before liftoff time, the launch director will conduct a “go poll,” asking people whether the rocket’s systems are ready and whether the weather conditions are favorable.
The last four minutes before launch are the “terminal count” when the rocket’s computer takes over the countdown process.
The seven engines in the booster will ignite 5.6 seconds before liftoff. That gives the computer a chance to check the performance of the engines before committing to liftoff. If anything is not quite right, it will shut down the engines.
If everything is good, the clamps holding the rocket will let go, and New Glenn will rise into the sky.
A crucial moment will come one minute, 39 seconds after launch as the rocket passes through what is known as max-Q, when atmospheric pressure on the rocket is greatest.
If it passes through that moment intact, the booster during the third minute of the flight will be done pushing the rocket upward and the engines will shut down. Twelve seconds later, it will drop away, and nine seconds after that, the second-stage engine will fire up.
Not long afterward, the fairing — the two halves of the nose cone protecting the payload — will jettison. At that altitude, the atmosphere is thin enough that the fairing is no longer needed.
Over the next few minutes, the booster will light up twice as it tries to land on a floating platform named Jacklyn, after Jeff Bezos’ mother, in the Atlantic Ocean.
Meanwhile, the second-stage engine will continue to fire until nearly 13 minutes after launch and then shut down.
Blue Origin will then switch on a prototype of its Blue Ring space tug, testing the communications, power and computer systems. It will remain attached to the rocket’s second stage.
About an hour after launch, the second stage will perform another engine burn to push it into a high elliptical orbit, coming as close as 1,500 miles from Earth and swinging out as far away as 12,000 miles. That is much higher than launches to low-Earth orbit, a few hundred miles up.
In an interview on Sunday, Jeff Bezos, the founder of Blue Origin, said that orbit will allow testing of the communications systems at a wide variety of altitudes. “And it puts the vehicle in a very harsh radiation environment, which we also want to test,” he said.
Then, almost six hours after launch, the mission will be over. The systems on the rocket stage and Blue Ring will be made safe and turned off, and they will continue their elliptical orbiting. Few other satellites occupy that region, making the chances slim that it will collide with anything else.
“It gets disposed in place,” Mr. Bezos said.
