What we're covering here
• NASA’s Artemis II mission is expected to liftoff from Kennedy Space Center in Florida today at 6:24 p.m. ET, carrying four astronauts on a journey around the moon.
• The historic and risky lunar venture will mark the first time astronauts have returned to the vicinity of the moon in more than 50 years.
• The crew, which includes NASA’s Reid Wiseman, Victor Glover, and Christina Koch along with Canadian Space Agency astronaut Jeremy Hansen, could break the distance record set by the Apollo program, traveling farther from Earth than any human ever has.
• This launch attempt, the mission’s first, comes after delays in February and March caused by technical issues with the rocket, including hydrogen leaks and a problem with helium flow.
Here are some of the best images from Artemis I
Artemis II may be the first crewed mission to come within the vicinity of the moon in more than 50 years, but the program to return humans to the moon kicked off with Artemis I.
The uncrewed mission embarked on a 25.5-day journey around the moon in November 2022 – and cameras on the spacecraft captured incredible views of Earth, the journey through space to the moon, dramatic glimpses of the cratered lunar surface, and a peek inside the capsule.
On the 12th day of the mission, the Orion capsule reached a maximum distance of nearly 270,000 miles from Earth before preparing to start the return journey.
Earth and the moon, each appearing as half spheres due to the angle of sunlight, can be seen nearly side by side in an especially stunning image.
To see more photos from this ambitious mission, see our gallery.
Here's where the Artemis II astronauts will travel
Eager to track every moment of the Artemis II mission? We’ll be covering each step of the lunar journey so you can follow along.
Here’s the path the crew will follow during their 10-day mission.
And if all goes according to plan, the crew will set a new distance record depending on their flight path, which is determined based on when they launch.
The current record for the farthest distance from Earth ever traveled by humans is 248,655 miles (400,171 kilometers), set by Apollo 13 in 1970.
While Artemis I already surpassed that record, the capsule did so without a crew.
For reference, the International Space Station hangs out in low-Earth orbit about 250 miles (about 402 kilometers) above the Earth.
The Artemis II astronauts will also have a different lunar flyby experience than the Apollo astronauts.
Orion will fly 4,000 to 6,000 miles (6,437 to 9,656 kilometers) above the lunar surface, much higher than the Apollo command modules that flew around the moon from 70 miles (112 kilometers) above its surface or the Lunar Reconnaissance Orbiter, a robotic mission circling the moon since 2009 that comes within 30 miles (48 kilometers) of its cratered face.
The crew will glimpse a part of the moon that Apollo astronauts were unable to see due to the orbits of their capsules.
Why is Artemis II not landing on the moon?
Artemis II will swing by the moon, but not land on it — why?
Artemis I, the program’s debut mission, was launched in November 2022 and went into orbit around the moon, lasting 25 days in total. However, it was uncrewed, so this is the first time that people will be on board the Artemis spacecraft, which includes the Orion capsule that will take the astronauts to the moon and the Space Launch System — the rocket that takes Orion into Earth orbit.
NASA’s priorities for Artemis II are very clear, Horn added: Crew safety and health comes first, which includes getting them back home. Vehicle safety and health is second, and the mission objectives only follow.
Meet Artemis II's all-star crew
The Artemis II crew is preparing to wake up and have breakfast around 9:45 a.m. ET — an important step if you’re about to set off on a 10-day mission around the moon and back.
Unlike the Apollo-era crews, which all included White American men from largely military backgrounds, Artemis II astronauts will represent several historic firsts.
But who are they? Let’s meet your Artemis II crew.
The crew includes NASA’s Reid Wiseman, a Navy test pilot and single father who will serve as commander of the mission; Victor Glover, a naval test pilot who will become the first Black person to travel to deep space; Christina Koch, an engineer and record-holding astronaut who will become the first woman to venture beyond Earth orbit; and the Canadian Space Agency’s Jeremy Hansen, a fighter pilot who will be the first non-NASA astronaut to join a lunar mission.
Learn more about their incredible stories here.
This leaky fuel has frustrated NASA’s launch controllers for years
There’s one notorious issue that NASA engineers will be keeping an eagle eye out for today: hydrogen leaks.
Hydrogen is the fuel used to power NASA’s SLS rocket. And leaks during loading are a major concern: Hydrogen is very easy to ignite and energetic, meaning that too much of it in one area poses the risk of a catastrophic explosion.
But it’s also the lightest molecule in the universe, and frustratingly tends to seep out of even the most miniscule, microscopic gaps. NASA knows this and plans to allow for at least a little leakage, but it must stay below 16%.
So why use hydrogen?
Ironically, the reason it’s such a fickle fuel is also one of the reasons it’s a great choice.
When selecting fuel for a rocket, the most important consideration is a concept called “specific impulse,” abbreviated as Isp. It’s a measure of how much thrust — or force — a rocket engine can generate with a set amount of fuel.
Hydrogen has the best specific impulse in the business, boasting the highest efficiency of all the rocket fuel options, “which is why we end up using it a lot,” said Adam Swanger, a senior principal investigator and cryogenics research engineer at NASA’s Kennedy Space Center.
But there’s one other less obvious reason that NASA uses hydrogen to power the SLS rocket: politics. Congress actually mandated that the space agency use legacy hardware from NASA’s retired Shuttle Program — thus forcing the agency to use hydrogen fuel.
Apollo was never that popular. But recent polls show broad support for Artemis
One underappreciated fact about the 20th-century space race: Apollo was never that popular in its time.
One poll from 1979 revealed just 53% of Americans believed cost of the moon landings were justified, and a similar split-perception continued through the 1990s.
Tides, however, have turned. A recent Gallop poll found 64% of Americans believe the high cost of our space programs are worth it.
And public perception is important.
The Artemis program has cost taxpayers roughly $100 billion since its inception — and it will take many billions more to realize the ambitious goals NASA has mapped out.
Keep in mind, however, that during the Apollo program, NASA had more than 4% of the entire national budget. Now, the space agency operates with less than half of one percent. (Spoiler: That’s why it has taken so long to go back to the moon.)
The daunting task ahead of NASA is to figure out how to fund its ambitious human exploration goals while still keeping up with its other important scientific endeavors. It’s up to Congress to decide how much money to put toward these projects, and the popularity and perception of spaceflight certainly plays a role.
The rocket is now fueling up on the launchpad
Now that the SLS rocket has been safely chilled down enough to receive a continuous flow of supercold propellant, mission teams have begun slowly loading it with liquid hydrogen.
Next, they’ll start a slow flow of liquid hydrogen before transitioning to a more rapid fueling phase for both propellants. The core stage will ultimately be loaded with 700,000 gallons of liquid oxygen and liquid hydrogen.
Weather is 80% favorable for today's launch attempt
With just over 10 hours to go before liftoff is expected to occur, sunny skies and few clouds are greeting NASA teams, spectators and journalists who have gathered at Kennedy Space Center.
Pop-up rain showers are a common occurrence along Florida’s space coast, but launch weather officers are confident that weather is 80% favorable for a liftoff attempt today.
While afternoon rain showers are likely, NASA’s weather officers expect them to move west of the launch site in the evening. The only concerns are clouds and breezy onshore winds.
“Artemis is a very resilient vehicle, so despite the breezes, it looks like that concern is minimal for our day of launch,” said Mark Burger, launch weather officer with the Space Force’s 45th Weather Squadron.
Artemis II launch director gives "go" for fueling the mega moon rocket
It’s go time for the Artemis II mission.
The towering Space Launch System rocket, illuminated by the sun rising over Kennedy Space Center in Florida, is ready to be fueled for its journey to space, according to Artemis Launch Director Charlie Blackwell-Thompson.
This crucial decision means that the fuel lines of the core stage, or main body, of the rocket, will now experience chilldown, which prepares the rocket for the loading of its propellants, superchilled liquid oxygen and liquid hydrogen, later this morning.
Here’s what to expect during today’s launch attempt
Welcome to launch attempt day for the Artemis II mission. The next few hours are sure to be eventful — and will hopefully lead to liftoff.
Here’s what to expect:
- The longest process of the day will be fueling the rocket with supercold liquid oxygen and liquid hydrogen. Fueling occurs in multiple phases and kicked off about 10 hours before takeoff.
- A few hours prior to launch, the astronauts will head to the White Room, an environmentally controlled staging area where the crew will don their helmets and gloves, before boarding the Orion spacecraft.
- Once the crew hatch is sealed and checks are carried out, the closeout crew will depart the launchpad.
- Twenty-five minutes prior to liftoff, the launch director will check in with all teams responsible for the launch to ensure that everyone agrees they are “go” for launch.
- Then, with 10 minutes to go, a computer that controls the rocket’s launch sequence, called the ground launch sequencer, will initiate terminal count. This is the final, and largely automated, phase of countdown.
- After the engines start up and the booster ignites, it’s time for liftoff.
- A few minutes after launch, the rocket boosters and launch abort system will separate from the spacecraft.
- And about eight minutes after liftoff, core stage MECO, or main engine cut-off, will occur, signaling the shutdown and separation of the rocket’s core stage from Orion — and the crew will experience weightlessness in space.
