The countdown has begun. Tonight, NASA will attempt to launch Artemis 2, the first crewed lunar mission since the Apollo era. This historic mission will send four astronauts on a trip around the Moon and back again—you won’t want to miss a single moment of it.
Ground teams at NASA’s Kennedy Space Center in Cape Canaveral, Florida, are in the midst of final preparations, targeting a launch window that will open at 6:24 p.m. ET today and remain open for two hours. Gizmodo will be following along all day to bring you the latest updates on countdown proceedings, the crew, and more. To watch the launch live, head to our watch page.
At T-0, NASA’s Space Launch System (SLS) rocket will propel the Orion spacecraft and its crew—consisting of NASA’s Reid Wiseman, Victor Glover, Christina Koch, and the Canadian Space Agency’s Jeremy Hansen—to low-Earth orbit. About 25 hours after launch, Orion will set course for the Moon. This will be the first time astronauts have departed low-Earth orbit in 54 years, and this time, they’re venturing deeper into space than ever before.
The structure of SLS
NASA’s super heavy-lift rocket is currently the only launch vehicle capable of sending the agency’s Orion spacecraft, four astronauts, and large cargo to the Moon on a single launch. It’s made up of two main components: a core stage and an upper stage.
The core stage stands more than 212 feet (65 meters) tall and stores 733,000 gallons (2,774,707 liters) of cryogenic propellant to power its four RS-25 engines. At T-0, the core stage’s solid rocket boosters will produce 8.8 million pounds (4 million kilograms) of thrust to blast off.
The upper stage, or interim cryogenic propulsion stage (ICPS), has one Rl10 engine that generates nearly 25,000 pounds (11,000) kilograms of thrust. After launch, this stage will separate from the rest of the rocket with Orion to adjust the spacecraft’s orbit in preparation for translunar injection.
Ground teams transition to fast fill for SLS upper stage
At 9:52 a.m. ET, the launch team transitioned to the fast fill of liquid hydrogen for the SLS rocket’s interim cryogenic propulsion stage (ICPS). With the chilldown phase complete, engineers are rapidly loading super-cold LH2 into the upper stage tanks to ensure they are fully fueled and ready to go for launch.
Liquid hydrogen chilldown begins
At 9:36 a.m. ET, the launch team began the liquid hydrogen chilldown for the the SLS rocket’s upper stage, also known as the interim cryogenic propulsion stage (ICPS).
This process gradually cools the ICPS fuel lines and hardware to cryogenic temperatures using super-cold LH2, according to NASA. Like the slow-fill phase earlier this morning, this process is essential to preventing thermal shock and ensuring the stage is properly conditioned for full propellant loading later today.
The ICPS has a critical role to play in Artemis 2. Shortly after launch, Orion and ICPS will separate from the rest of SLS. ICPS will then perform an initial burn to maintain Orion’s trajectory.
About 49 minutes into the flight, the ICPS will fire its engine again to raise the perigee—the lowest point of Orion’s orbit—to an altitude of 100 miles (161 kilometers) above Earth. It will then fire a third time to raise Orion into a high-Earth orbit. This will set the spacecraft up for the translunar injection that will put it on the path to the Moon.
Good morning, Artemis 2 crew!
Artemis 2 commander Reid Wiseman, pilot Victor Glover, and mission specialists Christina Koch and Jeremy Hansen officially began their launch day with a scheduled wake-up call at 9:25 a.m. ET.
This is a historic crew. Glover will be the first person of color to visit the lunar environment, Koch the first woman, and Hansen the first Canadian—and first non-American—to make the journey. These firsts signal that NASA has truly entered a new era of human spaceflight—one that is far more diverse than the Apollo era.
Ground teams transition to fast fill
At 9:04 a.m. ET, the launch team transitioned to the fast fill of liquid hydrogen into the SLS core stage.
With the slow fill phase complete, this phase will rapidly load cryogenic LH2 into the rocket’s massive tanks, bringing them closer to full capacity, according to NASA. Because the hardware has now been thermally conditioned, teams can safely increase the fueling rate.
Liquid hydrogen is a tricky fuel to work with, which is a large part of why the SLS has experienced so many hydrogen leaks in the past. As the smallest molecule—consisting of two bonded hydrogen atoms—LH2 can escape through minuscule gaps in seals and joints. The extremely cold temperature of the fuel, which is -423 degrees Fahrenheit (-253 degrees Celsius), can also cause these hardware elements to become brittle and crack.
Good morning, happy Artemis 2 launch day!
Today is a very exciting day. In a matter of hours, humanity’s decades-long hiatus from crewed lunar spaceflight may finally come to an end. Here’s where Artemis 2 countdown proceedings currently stand.
Artemis Launch Director Charlie Blackwell-Thompson gave the official “go” for tanking at 7:33 a.m. ET. At 8:35 a.m., the launch team initiated the slow fill of liquid hydrogen (LH2) and liquid oxygen (LOX) into the SLS core stage. According to NASA, this phase introduces the super-cold propellants at a controlled rate to allow the rocket’s plumbing and tanks to gradually adjust to cryogenic temperatures. This minimizes stress on hardware and prepares the rocket for faster fueling later today.
Essentially, ground teams are setting the stage for full tanking operations. Tanking will be the most challenging part of today’s launch preparations, and SLS is known to act up during this process. Back in February, hydrogen leaks derailed the first Artemis 2 wet dress rehearsal. Here’s hoping tanking goes smoothly today.
