The Space Launch System rocket and Orion spacecraft are scheduled to lift off between 2:17 and 4:17 p.m. ET Saturday from NASA’s Kennedy Space Center in Florida.
Although there is no crew aboard, the mission is the first step of the Artemis program, which aims to return humans to the moon and eventually land them on Mars.
There is a 60% chance of favorable weather conditions for the launch, with chances increasing to 80% favorable toward the end of the window, weather officer Melody Lovin said during a Friday morning news conference.
If the rocket is unable to launch Saturday, the next possible launch window would be Monday.
Once it launches, the Orion spacecraft will enter a distant retrograde orbit of the moon and travel 40,000 miles beyond it, going farther than any spacecraft intended to carry humans. Crews will ride aboard Artemis II on a similar trajectory in 2024, and astronauts are slated to arrive at the lunar south pole in late 2025 on the Artemis III mission.
The Artemis program aims to land the first woman and the first person of color on the moon.
The agency will share live views and coverage in English and Spanish before, during and after the Artemis I launch on its website and on NASA TV. The broadcast will begin at 5:45 a.m. ET as supercold propellant is loaded into the SLS rocket.
After the launch, NASA will conduct a briefing and later Saturday will share the first Earth views from cameras aboard the Orion spacecraft. The Virtual Telescope Project will attempt to share live views of Orion on its way to the moon shortly after launch.
Orion’s journey will last about 38 days as it travels to the moon, loops around it and returns to Earth — traveling 1.3 million miles (2.1 million kilometers). The capsule will splash down in the Pacific Ocean off San Diego on October 11.
Cameras inside and outside of Orion will share images and video throughout the mission, including live views from the Callisto experiment, which will capture a stream of a mannequin called Commander Moonikin Campos in the commander’s seat.
If you have an Amazon Alexa-enabled device, you can ask it about the mission’s location each day.
Here’s everything you can expect before, during and after the launch.
Counting down to launch
Early Saturday, the launch team will conduct a briefing on weather conditions and decide whether to begin fueling the rocket.
If everything looks good, the team will begin fueling the rocket’s core stage and then move on to fueling its upper stage. Afterward, the team will top off and replenish any of the liquid hydrogen and liquid oxygen that dissipates during the fueling process.
About 50 minutes before launch, the final NASA test director briefing will occur. The launch director will poll the team to make sure every station is a “go” 15 minutes ahead of liftoff.
At 10 minutes and counting, things kick into high gear as the spacecraft and rocket go through the final steps. Much of the action takes place in the final minute as the ground launch sequencer sends the command for the rocket flight computer’s automated launching sequencer to take over.
In the last few seconds, hydrogen will burn off, the four RS-25 engines will start, resulting in booster ignition and liftoff at T minus zero.
Journey to the moon
The solid rocket boosters will separate from the spacecraft about two minutes into the flight and splash down in the Atlantic Ocean, with other components also jettisoning shortly afterward.
The core stage of the rocket will separate about eight minutes later and fall toward the Pacific, allowing for Orion’s solar array wings to deploy.
The perigee raise maneuver will occur about 12 minutes after launch, when the interim cryogenic propulsion stage experiences a burn to raise Orion’s altitude so it doesn’t reenter the Earth’s atmosphere.
Shortly afterward is the trans-lunar injection burn, when the ICPS boosts Orion’s speed from 17,500 miles per hour (28,163 kilometers per hour) to 22,600 miles per hour (36,371 kilometers per hour) to escape the pull of Earth’s gravity and set off for the moon.
After this burn, the ICPS will separate from Orion.
Around 9:45 p.m. ET, Orion will make its first outbound trajectory correction burn using the European Service Module, which provides the spacecraft with power, propulsion and thermal control. This maneuver will put Orion on a path to the moon.
The next few days after launch, Orion will venture out to the moon, coming within 60 miles (96 kilometers) during its closest approach on day six of the journey. The service module will place Orion in a distant retrograde orbit around the moon on day 10.
Orion will also surpass the distance record of 248,654 miles (400,169 kilometers) — set by Apollo 13 in 1970 — on day 10 when it loops around the moon.
The spacecraft will achieve its maximum distance from Earth of 280,000 miles (450,616 kilometers) on September 23 when it ventures 40,000 miles (64,373 kilometers) beyond the moon.
Orion will make its second-closest approach of the lunar surface, coming within 500 miles (804 kilometers), on October 5. The service module will experience a burn that enables the moon’s gravity to slingshot Orion back on its way to Earth.
Just before reentering Earth’s atmosphere, the service module will separate from Orion. The spacecraft will hit the top of Earth’s atmosphere moving at about 25,000 miles per hour (40,233 kilometers per hour), and its heat shield will experience temperatures of nearly 5,000 degrees Fahrenheit (2,760 degrees Celsius).
The atmosphere will slow Orion down to about 300 miles per hour (482 kilometers per hour), and a series of parachutes will slow it down to less than 20 miles per hour (32 kilometers per hour) before it splashes down in the Pacific at 2:10 p.m. ET on October 11.
Splashdown will be streamed live from NASA’s website, with views from 17 cameras aboard the recovery ship and helicopters waiting for Orion’s return.
The landing and recovery team will collect the Orion capsule, and data from the spacecraft will determine the lessons learned before humans return to the moon.