Artemis II Launch

Terminal Count Pre-Checks

Commentator: Okay. Well, there you heard it. They’re getting ready to start terminal count.

NTD: RSR, NTD.

RSR: RSR.

NTD: FNA, arm rotation enable at this time, please.

Commentator: It’s currently at T-minus 10 minutes. Once we wrap up this last bit of work, we’re going to start that clock.

FNA: Thank you.

NTD: Integrity rew, close and lock visors.

Commentator: You heard an issue worked in real time with telemetry lock on the Orion. It was transitory. It was very short. They checked the data, confirmed that they had a good lock. This was with the S-band transmitter on the Orion. Worked through that issue, looked at the data, and cleared it. All with the world watching. Impressive work by the launch team. So we have a two-hour window, which starts in just a few minutes at 6:24 p.m. Eastern Time and goes until 8:24 p.m. Eastern Time.

NTD: And ECL, NTD will be waiting for your verification on the short purge.

ECL: ECL copies.

NTD: And for all personnel, once we get that short purge verification, we’ll verify that we are clear to go and then we’ll proceed with the terminal count. ECL, time estimate?

ECL: About a minute.

NTD: Copy.

Commentator: So we’re going into the launch window, but not by much it looks like. Just wrapping up some final work. And once that’s completed, you’ll hear NASA Test Director Jeff Spalding ask for the ground launch sequencer operator to go ahead and start the clock. The launch control system in the firing room acts like a conductor of an orchestra, executing hundreds of commands in precise order and timing. It’s all autonomous.

ECL: NTD, ECL, 212, short purge initiation is verified.

NTD: All right, copy that. And we’re cleared from cutouts. And with that, we’re going to resume the clock momentarily. And CGLS, you can resume the clock on your mark.

GLS: GLS copies. Three, two, one, mark.

Terminal Count Execution (T-10min)

GLS: GLS mainline has been initiated. T-minus 10 minutes and counting.

Commentator: And that begins terminal count. Our new T-0 is 6:35 p.m. Eastern time. We are now counting down to liftoff of Artemis II. From now on, you’re going to hear two voices on the loops if everything goes nominally: NASA test director Jeff Spalding, who’s directly managing the launch team, and Alex Pendelos, the GLS operator who closely monitors the software. He has the ability to stop and restart the countdown. A lot of people ask about whether there’s a launch button. There certainly is not.

NTD: Houston Flight and ROC, our new T-0 is 22:35:12.

HUSFLT: Houston Flight copies.

ROC: ROC copies. 22:35:12.

NTD: Affirm.

Commentator: There you heard confirmation of the exact T-0, 6:35 and 12 seconds PM Eastern time. But as I was saying, there’s no launch button, this is autonomous, but there is a button that keeps you from launching, and that button allows the GLS operator to pause the countdown outside of terminal count and during terminal count and submit a hold to the next holding point. So the clock won’t stop right away if there’s an issue. We’ll go to the next stable holding point. This is how GLS configures the rocket and ground systems to a stable point where they can stop the countdown if that’s needed. But right now, we are counting down. Our next big milestone looking to retract the crew access arm.

GLS: GLS is go for crew access arm retract.

Commentator: And there you see the crew access arm moving away. That’s the path that the astronauts took to ingress into the rocket. Until this point, that was their way off the pad if they needed to evacuate. But now with that arm retracting, the backup transitions to a launch abort system. And they’ll begin arming that shortly. Of course, the launch abort system—great shot there of the crew access arm retracting away—the launch abort system is the tower at the top, and that’s what would pull Orion and its crew off the top of the rocket in case of an emergency, whether it’s on the ground or in flight. This is critical safety hardware that protects the lives of the astronauts.

Starting at T-minus six minutes, the GLS will start bringing that and other high-energy core stage pressurization. Weather is 90% go. The range is go. All systems are go.

GLS: GLS is go for core stage tank pressurization.

Commentator: The replenish valve for the liquid hydrogen tank has now closed and that tank is beginning to pressurize to flight levels because that hydrogen is naturally boiling inside the tank. We’ll get the liquid oxygen tank a little later in the count. Now the team is waiting for verification that if needed, the Artemis II crew could use the launch abort system to pull Orion safely off the top of the rocket in an emergency. Let’s listen in for that call.

GLS: GLS verifies LAS capability available.

NTD: And CDR, do you copy?

CDR: CDR copies, LAS available.

Commentator: That’s great news and you heard the NTD verify that with the commander of the mission.

GLS: GLS is go for FTS arm.

Commentator: Now work is being done to arm the flight termination system. This is so the range safety can send a flight termination command if the rocket flies too far off track. There is a brief built-in delay so the launch abort system has time to pull the astronauts to safety first.

GLS: Go for LH2 high-flow bleed check.

Commentator: All right, the RS-25 engines, all four of them, are in the proper temperature range for launch.

GLS: GLS is go for core stage APU start.

Commentator: Core stage APU start. Those are auxiliary power units, high-speed turbines which provide pressure to hydraulic pumps that steer the RS-25 engines. We’re going to see a gimbal test a little later at T-minus 2 minutes and 30 seconds. This is what allows that to happen. Coming up in about 20 seconds, we’re listening for go for purge sequence four. That’s a helium purge of the four core stage engines downstream of the propellant valve. This gets all the air and moisture out of there.

GLS: GLS is go for purge sequence four.

Commentator: Moving through the milestones. All is looking good. Coming up in just a few seconds, we’re going to get that thrust vector control actuator test.

GLS: Vector Control Actuator Test.

Commentator: This is a gimbling of the engines. There are the four RS-25s, three of them Shuttle Heritage, one of them built from shuttle parts. And there you see them moving. Now we’re going to start moving the power from both the upper stage and the lower stage of the rocket to internal, taking ground power away and now going to battery power.

GLS: GLS is go for upper stage internal power.

Commentator: Power is removed from the rocket’s upper stage, the ICPS, and it’s been switched to battery. Same milestone for the lower core stage coming up at T-minus one minute and 30 seconds. Right now, the four-person Artemis II crew is 248,000 miles away from the moon. And if all goes well, they will fly by it in six days.

GLS: GLS is go for core stage to internal power.

Commentator: All right, there’s the rocket’s core stage, which houses three flight computers, is now on its own power. There’s no more hold time because there’s no more margin on these batteries, so we would have to recycle back to T-minus 10 to recharge if we had a hold. One minute. Right now the rocket does not know what the T-0 is, but coming up at T-minus 33 seconds, control shifts from the ground launch sequencer to the rocket’s onboard autonomous launch sequencer, or ALS. The rocket will count itself down, but honor any holds that could come from the ground. Now shortly after liftoff, Houston will take control of the rocket and my colleague Gary Jordan will take over commentary.

GLS: GLS, go for ALS.

Liftoff

Commentator: Great call out. The rocket is on its own. Four brave explorers ready to ride the most powerful rocket NASA has ever launched.

Sound suppression water is flowing.

And here we go. 10, 9, 8, 7, RS-25 engines lit, 4, 3, 2, 1, booster ignition, and liftoff!

The crew of Artemis II now bound for the Moon. Humanity’s next great voyage begins.

Ground: Good roll, pitch.

CDR: Roger, roll pitch.