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NASA's Artemis 1 moon mission: Live updates

NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard is seen atop a mobile launcher at Launch Complex 39B, Sunday, April 3, 2022, as the Artemis I launch team conducts the wet dress rehearsal test at NASA’s Kennedy Space Center in Florida.
(Image: © NASA/Joel Kowsky)

NASA's Artemis 1 moon mission will be the agency's first big step toward returning astronauts to the lunar surface. 

Formerly known as Exploration Mission 1 (EM-1), Artemis 1 will be the first test flight of the agency's new Space Launch System megarocket and the Orion crew capsule.

The SLS rocket will launch the uncrewed Orion spacecraft on an approximately 26-day mission, during which it will spend six days orbiting the moon before returning to Earth. 

Artemis 1 is currently scheduled to launch no earlier than late Aug. 29, 2022, from Launch Complex 39B at NASA's Kennedy Space Center in Florida. Check back here for live updates on the mission.

Related: NASA's Artemis 1 moon mission explained in photos

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Artemis 1 moon rocket rollout moved up to Aug. 16

(Image credit: NASA/Ben Smegelsky)

NASA has moved up the launch pad rollout of its Artemis 1 moon rocket, the first Space Launch System, by two days. The rocket will now roll out its Launch Pad 39B site on Tueday, Aug. 16, (two days earlier than planned) to begin final preparations for its Aug. 29 launch to the moon

Officials with NASA's Ground Systems team announced the schedule change on Twitter.

"ARTEMIS I UPDATE: The rollout of @NASA_SLS & @NASA_Orion to Launch Pad 39B has now moved up to tomorrow, the evening of Aug. 16, ahead of the targeted Aug. 29 launch. Stay tuned for more information as well as ongoing coverage," NASA wrote in the update (opens in new tab).

The rollout of Artemis 1's SLS will be webcast live on NASA TV. It will come amid a series of teleconferences this week to discuss the Artemis 1 moon mission. Here's a schedule of events for the week, which you'll be able to watch for free on this page

  • Monday, Aug. 15, at 5 p.m. EDT: Artemis 1 lunar science payloads teleconference.
  • Tuesday, Aug. 16, at 12 p.m. EDT: Artemis 1 technology & solar system science teleconference.
  • Tuesday, Aug. 16, evening: Artemis 1 moon rocket rollout.
  • Wednesday, Aug. 17, at 12 p.m. EDT: Artemis 1 radiation science teleconference.
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Artemis 1 cleared for launch; Space.com on site

The Artemis 1 moon megarocket is cleared for launch for its debut mission, no earlier than Aug. 29. The European Space Agency released a video (visible above) celebrating the milestone for the mission, which is led by NASA.

Space.com is on site at NASA's Johnson Space Center in Houston talking to officials about the progress of Artemis 1, which aims to circle the moon and come back to Earth uncrewed on a mission lasting more than a month. We'll keep you tuned into our coverage as the briefings progress.

On Aug. 3, NASA officials said the rocket is on track for launch preparations following a "wet dress rehearsal" fueling test in June that revealed a few issues. The agency also framed this mission as critical to get the Space Launch System rocket and Orion spacecraft ready for future human missions as the system collects science on the moon and on human effects on spaceflight.

Read more: Artemis 1 moon mission readies for crucial test for future crewed flights

Artemis 1 NASA preview today (Wednesday) at 11 a.m. EDT

NASA's will hold a press conference Wednesday (Aug. 3) at 11 a.m. EDT (1500 GMT) to give a general overview of the Artemis 1 lunar mission, which you can watch for free in the YouTube stream above. 

The briefing is expected to last an hour and will feature the following speakers:

  • NASA Administrator Bill Nelson;
  • Bhavya Lal, associate administrator for technology, policy, and strategy at NASA's headquarters;
  • Mike Sarafin, Artemis 1 mission manager with NASA HQ;
  • Charlie Blackwell-Thompson, Artemis 1 launch director at NASA's Kennedy Space Center (KSC) in Florida (the mission's launch site); 
  • John Honeycutt, Space Launch System program manager with NASA's Marshall Space Flight Center in Huntsville, Ala.; 
  • Howard Hu, Orion program manager, with NASA's Johnson Space Center (JSC) in Houston.

After Wednesday's briefing, NASA will host an in-person media day concerning Artemis 1 at its Johnson Space Center, where astronaut training takes place.

Artemis 1 will send an Orion spacecraft to the moon atop a Space Launch System megabooster, in an uncrewed mission meant to prepare for future human excursions. The mission will also launch 10 cubesats targeting several off-Earth science missions.

The exact duration of Artemis 1 will depend on orbital dynamics at the time of launch; an Aug. 29 launch (the nominal date so far) would see a 42-day flight, for example, but a Sept. 2 liftoff would kick off a 39-day mission.

Read more: NASA will preview its Artemis 1 moon mission this week. Here's how to watch for free.

Artemis 1 targets Aug. 29 launch date

NASA’s Artemis 1 moon rocket — carried atop the crawler-transporter 2 vehicle — as it approaches Launch Pad 39B at the agency’s Kennedy Space Center in Florida. NASA will roll SLS and Orion back to the Vehicle Assembly Building (VAB) at Kennedy next week to prepare the rocket and spacecraft for launch.

NASA’s Artemis 1 moon rocket — carried atop the crawler-transporter 2 vehicle — as it approaches Launch Pad 39B at the agency’s Kennedy Space Center in Florida.  (Image credit: NASA/Ben Smegelsky)

NASA's moon megarocket is scheduled to fly its first mission as soon as late August, pending testing and reviews of all the components of Artemis 1.

The agency announced today (July 20) that it has three "placeholder" launch dates for the uncrewed test flight around the moon: Aug. 29, Sept. 2 and Sept. 5. 

"It's not an agency commitment," Jim Free, NASA's associate administrator of exploration systems, said of the interim launch dates during a teleconference with reporters. The agency, he said, will make a commitment closer to the launch date pending work on several outstanding items from Artemis 1's wet dress rehearsal that concluded June 20.

Learn more at Space.com here

Artemis 1 reaches end of terminal count

NASA's Artemis 1 moon mission has reached the end of terminal count, effectively wrapping up its two-day-long wet dress rehearsal. The milestone came today (June 20) at 7:37 p.m. EDT (2337 GMT), after which the mission team began safing Artemis 1's huge Space Launch System rocket.

Terminal count ended at T-29 seconds before (simulated) engine ignition rather than T-9 seconds, as originally planned. That change resulted because the mission team "masked" three issues that cropped up today during the test, including a leak of liquid-hydrogen fuel, agency officials said. Masking allowed the countdown to proceed despite the issues, which would have raised red flags on the day of an actual launch.

Artemis 1 begins wet dress rehearsal's terminal count

NASA's Artemis 1 moon mission has begun terminal count in its wet dress rehearsal,. The countdown clock began ticking down from T-10 minutes at 7:33 p.m. EDT (2333 GMT).

Artemis 1 'go' for T-10 countdown

The Artemis 1 team has decided to proceed with a simulated launch countdown that will end at T-10 seconds, NASA officials announced this evening (opens in new tab) (June 20). That countdown will be performed in a modified configuration, one that masks a hydrogen leak discovered earlier today.

Artemis 1 moon rocket fully fueled

NASA has fully fueled its Space Launch System (SLS) megarocket, notching a huge milestone in the "wet dress rehearsal" for its Artemis 1 moon mission, agency officials announced via Twitter this evening (opens in new tab) (June 20). 

Some issues have cropped up during the wet dress, however; for example, the Artemis 1 team noticed a hydrogen leak in one of the SLS "quick disconnect" lines. But the wet dress may proceed to its conclusion today even if that leak is not fixed.

"The team may decide to continue terminal count with certain issues masked in order to get further into the testing for today's wet dress rehearsal," NASA officials said in another tweet this evening (opens in new tab)

Artemis 1 team diagnoses hydrogen leak problem

The Artemis 1 team has determined that the hydrogen leak in one of the Space Launch System (SLS) rocket's "quick disconnect" lines resulted from a faulty seal on the rocket side of the cable, NASA officials said during an update this afternoon (June 20). The team is still working through its next steps and has not yet set a T-0 time that would mark the end of the "wet dress rehearsal" test of the Artemis 1 SLS and Orion capsule.

NASA recalibrating new T-0 for Artemis 1 wet dress rehearsal

NASA is recalibrating the T-0 for its Artemis 1 wet dress rehearsal after failing in an attempt to fix a hydrogen leak in a "quick disconnect" line in the Space Launch System rocket's core stage, agency officials said in an update this afternoon (June 20).

Technicians tried warming up and then cooling down the quick disconnect, hoping that would reseat the hardware and seal the leak. But it didn't work, so Artemis 1 team members are "putting their heads together and seeing if they can come up with any other options to seal that leak," NASA spokesperson Derrol Nail said this afternoon during the agency's webcast of the wet dress rehearsal. 

Nail added that the team is also trying to come up with a new T-0 , the milestone that will wrap up the wet dress rehearsal. The current T-0 is 4:38 p.m. EDT (2038 GMT), but it's been apparent for some time now that Artemis 1 would not hit that mark.

Three of four SLS propellant tanks now filled

Three of the four propellant tanks on the Artemis 1 Space Launch System rocket are now filled, and the fourth could be tanked up soon, NASA officials in a Twitter update this afternoon (opens in new tab) (June 20). 

"Liquid oxygen is currently at fast fill for upper stage. Team is working a plan to reseal at the hydrogen leak," the tweet reads, in part. That leak was spotted earlier today at a "quick disconnect" on the SLS core stage.

Teams at NASA's Kennedy Space Center in Florida continue troubleshooting the hydrogen leak at the core stage quick disconnect of the Space Launch System rocket, which stopped the fueling operation of the Artemis 1 wet dress rehearsal test earlier today. 

Teams from Boeing as well as NASA are on site trying to seal the leak, hoping to be able to continue with the test, although it's unlikely that T-0 will occur at 4:38 p.m. EDT (2038 GMT) as still officially planned. 

"Team is working to manually adjust the LOX pressure in upper stage to get back into tanking," NASA said on Twitter (opens in new tab).

The fueling of the rocket's upper stage has been completed.

Hydrogen leak troubleshooting ongoing during Artemis 1 tanking

Artemis 1 teams are currently troubleshooting the leak at the core stage quick disconnect. 

"This includes manually configuring valves to reduce the pressure on the upper stage," spokesperson Derrol Nail said on NASA Television. 

Whilst troubleshooting continues, there is no plan to intervene with the small grass fire that is burning near the hydrogen flare stack, according to Nail. 

As the grass is burning towards a dirt road the belief by the launch team is that it will burn out once it gets to the road. 

"It would be more risky to send a team out there to put it out," Nail said.  

It is still unclear what impacts these issues would have, if any, on the planned T-0 during the wet dress rehearsal, currently set for 4:38 p.m. EDT (2038 GMT).

Hydrogen leak, grass fire discovered during Artemis 1 tanking

NASA says Artemis 1 teams are "working on an issue with the liquid hydrogen" during tanking operations of the core stage, among other issues.

"They are getting some data that says there's a leak, a liquid hydrogen leak, in the quick disconnect that takes the bleed for the engines," spokesperson Derrol Nail said on NASA Television around 2:07 p.m. EDT (1807 GMT).

"The team is currently evaluating that situation," Nail said. "Of course, any leak of liquid hydrogen is something ... to be concerned about for the launch team. This is a hazardous gas. They want to understand the situation fully before they take any action."

Nail added there are more issues forthcoming: there appears to have been a pressure limit exceeded during fueling in the liquid oxygen for the upper stage, and a small grass fire has emerged nearby the launch pad. 

It is unclear what the grass fire was caused by, and agency officials have their cameras on the area to monitor the smoke coming out of the grass.  

It is unclear what impacts these issues would have, if any, to the planned T-0 during the wet dress rehearsal, currently set for 4:38 p.m. EDT (2038 GMT).

Tanking graphic during Artemis 1 tanking

Tanking procedures for Artemis 1's wet dress rehearsal during a graphic released on Monday (June 20).

Tanking procedures for Artemis 1's wet dress rehearsal during a graphic released on Monday (June 20). (Image credit: NASA)

The above graphic was released on NASA Television at 1:15 p.m. EDT (1715 GMT) showing the progress of tanking operations in the Space Launch System's core stage. The rocket is being fueled during the wet dress rehearsal of Artemis 1, which is expected to wrap up later on Monday afternoon (June 20).

Update, 1:32 p.m. EDT / 1732 GMT: While saying the core stage is fully filled, NASA added that the graphic showed the incorrect temperature for the liquid hydrogen. The correct temperature should have read -423 degrees Fahrenheit (-253 degrees Celsius).

Core stage almost completed on tanking; upper stage 'a little behind'

The core stage of the Space Launch System is almost completed tanking. Liquid hydrogen is fully tanked, while liquid oxygen is at 90%, NASA spokesperson Derrol Nail said during a Monday (June 20) update at 1 p.m. EDT (1700 GMT) on NASA Television.

The upper stage entered chilldown of its gas lines at 1:03 p.m. EDT (1703 GMT) to prepare it for entry of the cryogenic gas, Nail added.

"We're running a little behind on the tanking for the upper stage, probably about a half hour or so," Nail added. "Tweaking of an upper stage skid took a little longer than expected."

So far, the T-0 in the wet dress rehearsal countdown remains at 4:38 p.m. EDT (2038 GMT) following now-resolved delays from early in the morning EDT. Preparations for the test have been running for nearly two days since a call to stations at 5 p.m. EDT (2100 GMT) on Saturday (June 18).

Liquid hydrogen reaches 'topping' stage

With the core stage hydrogen tank at 98% full, the tank is now in "topping" procedures to make sure the liquid gas is fully ready for the wet dress rehearsal in the coming hours, NASA Television said in an update at 12:35 p.m. EDT (1635 GMT).

The liquid oxygen tank in the core stage is at 76% full, and all operations are still proceeding to a T-0 in the wet dress rehearsal test at 4:38 p.m. EDT (2038 GMT).

Liquid oxygen and hydrogen beyond 50% filled

Liquid hydrogen and liquid oxygen levels are beyond half filled, NASA said in an update around 12:15 p.m. EDT (1715 GMT). Liquid hydrogen in the Space Launch System megabooster core stage is at 67% full, while liquid hydrogen at 63%. 

Engineers are also preparing the upper stage of the rocket for fueling, which will go much faster than the core stage, according to NASA Television spokesperson Derrol Nail. 

T-0 on the simulated countdown is still expected at 4:38 p.m. EDT (2038 GMT), following now resolved delays from early in the morning EDT. You can listen in live on NASA's website (opens in new tab).

Artemis 1 'go' in prep for liquid hydrogen tanking

Engineers just received the "go" to prepare the upper stage of the Space Launch System (SLS) for liquid hydrogen tanking, beginning with a helium purge, according to NASA Television.

Liquid hydrogen enters 'fast fill'

Liquid hydrogen tanking is now entering a 'fast fill' phase as engineering teams work to get the Space Launch System megarocket tanked for the wet dress rehearsal of Artemis 1 later today, NASA officials said in an update around 11:30 a.m. EDT (1530 GMT).

Liquid oxygen and liquid hydrogen are being tanked at the same time, but the flows on each gas are being adjusted. Hydrogen is flowing a bit faster and oxygen is flowing a bit slower, explained spokesperson Derrol Nail in the update on NASA Television.

The aim is to avoid an "aft strut constraint", Nail said. Aft struts are horizontal attachment points between the solid rocket boosters on either side of the core stage of SLS.

"The vehicle moves during fueling. It's very much alive. As the super-chilled propellants go into that tank, it [the vehicle] becomes heavier," Nail said. 

The metal on the tanks also shrinks slightly due to the cryogenic temperatures of the hydrogen and oxygen, he added. "For that reason, the propellants are put in in proportion to each other."

The liquid hydrogen tank, at 537,000 gallons (2.4 million liters), is expected to finish before the liquid oxygen tank at 196,000 gallons (roughly 740,000 liters), Nail said. Liquid hydrogen is much less dense than liquid oxygen. 

The oxygen tank is roughly 38% filled as of the update time, while the hydrogen tank stands at less than 5%; the oxygen tank is not allowed to exceed 49% filled until the hydrogen tank gets to at least 5%, according to NASA.

Artemis 1 teams adjust liquid oxygen and hydrogen flow

Liquid hydrogen is now flowing during the Artemis 1 wet dress rehearsal, NASA officials said around 11:10 a.m. EDT (1500 GMT) on Monday (June 20), confirming that announcement in an agency tweet (opens in new tab).

As liquid hydrogen tanking proceeds in the Space Launch System megarocket, the hydrogen's flow rate will be slightly accelerated in light of liquid oxygen tanking operations, which have been ongoing for about an hour.

The liquid hydrogen team anticipates they will slightly accelerate their flow of gas, while the liquid oxygen team plans to slow down their rate, NASA spokesperson Derrol Nail said during a NASA Television update.

That's because liquid hydrogen must be filled up to at least 5% in the SLS tank before liquid oxygen loading is authorized beyond 49% levels, Nail said. (Current levels are at 15% for liquid oxygen, he noted, so slowing down the oxygen flow is a precaution.)

Teams appear to be carefully adjusting these oxygen-hydrogen flows to reduce loads on the SLS during tanking, although NASA Television did not directly confirm that. The procedure is called an "aft strut constraint." The SLS has four struts securing the core stage to the boosters when the megarocket is stacked on the mobile launcher, according to NASA documentation (opens in new tab).

Artemis 1 begins slow fill of hydrogen

NASA has given the go for Artemis 1 to begin "slow fill" of liquid hydrogen in preparation for the wet dress rehearsal, the agency said on NASA Television Monday (June 20) around 10:42 a.m. EDT (1442 GMT).

Liquid hydrogen will then be authorized for a "fast fill", providing that tanking operations proceed as planned. The milestone was confirmed on the agency's Exploration Ground Systems Twitter account in a brief tweet (opens in new tab).

"The reason for that [slow fill] is to properly condition the vehicle," spokesperson Derrol Nail said on NASA Television. "The engineers are trying to prevent thermal shock to the system by flowing too much super-chilled propellant too fast."

NASA gives 'go' for liquid hydrogen tank filling

Engineers have a "go" to proceed for liquid hydrogen tank filling, NASA Television said in an update Monday (June 20) around 10:30 a.m. EDT (1430 GMT). 

The milestone was confirmed on the agency's Exploration Ground Systems Twitter account (opens in new tab) at 10:33 a.m. EDT (1433 GMT).

"This is a major milestone," spokesperson Derrol Nail said on NASA TV. "As you may recall from previous wet dress rehearsals, there was a leak ...the umbilical leak was fixed, so this is a big moment for the team."

NASA had made multiple attempts to perform the wet dress rehearsal in April, but ultimately pulled the Space Launch System and Orion spacecraft stack back to NASA's Kennedy Space Center's Vehicle Assembly Building to address the hydrogen leak issue.

Tanking operations are ongoing. Liquid oxygen entered a "fast fill" phase earlier in the hour, and liquid hydrogen lines are now being pre-chilled in preparation for tanking.

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Core stage liquid oxygen enters 'fast fill'

Liquid oxygen is now proceeding at a fast fill in preparation for Artemis 1 wet dress rehearsal operations, according to a NASA Television update and a brief tweet (opens in new tab) from the agency's Exploration Ground Systems account.

Core stage liquid oxygen enters 'slow fill'

The liquid oxygen for the Space Launch System's core stage has entered the "slow fill" part of the tanking process after chilling of the oxygen to cryogenic temperatures completed, according to an announcement from NASA Television.

"Core stage LOX [liquid oxygen] chilldown ... is complete and the team has now begun slow fill of liquid oxygen into the tank," NASA's Exploration Ground Systems account confirmed (opens in new tab) on Twitter at 10:08 a.m. EDT (1408 GMT).

The slow fill will take about two hours and 40 minutes to complete, which will be the longest process during wet dress rehearsal operations. Chilling for liquid hydrogen will begin in less than 10 minutes, spokesperson Derrol Nail said on NASA Television at 10:12 a.m. EDT (1412 GMT).

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Tanking ongoing for Artemis 1 wet dress rehearsal

NASA has confirmed tanking is ongoing during the Artemis 1 wet dress rehearsal on NASA Television, its Artemis blog and a tweet from the Exploration Ground Systems account, embedded below.

"The process for filling the core stage tank begins with the chill down, or cooling, of the propellant lines to load the liquid oxygen and liquid hydrogen in preparation for tanking," NASA officials said in the blog post, published Monday (June 20) at 9:38 a.m. EDT (1338 GMT). 

"The team will slowly fill liquid oxygen into the core stage tank with the fast fill beginning soon after," the post added. "Teams will then proceed to slowly fill the core stage’s liquid hydrogen tank, followed by fast fill."

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New eight-minute delay in exiting the hold

NASA expects to exit the lengthened test hold eight minutes later than expected. The new exit time will be 9:28 a.m. EDT (1328 GMT), allowing Artemis 1 wet dress rehearsal operations to proceed, agency officials said during an update on NASA Television.

"The team is configuring the launch vehicle to get ready for cryogenic tanking," agency spokesperson Derrol Nail said during the update, delivered around 9:20 a.m. EDT (1320 GMT).

The hold was lengthened about two hours beyond its expected conclusion at 7:30 a.m. EDT (1130 GMT) due to issues with a backup gaseous nitrogen line, issues which all appear to be resolved now. The nitrogen is required to purge harmful gases during tanking, among other uses.

Should the tanking proceed to plan after this point, the new T-0 (simulated liftoff) would be at 4:38 p.m. EDT (2038 GMT), Nail added during the update.

Launch director gives 'go' for cryogenic tanking

Artemis 1 on the launch pad during wet dress rehearsal operations on June 20, 2022.

(Image credit: NASA)

NASA launch director Charlie Blackwell-Thompson gave the "go" for cryogenic tanking to begin on the Artemis 1 wet dress rehearsal, according to a livestreamed update on NASA Television shortly before 9 a.m. EDT (1300 GMT). 

The cryogenic cooling was expected to begin at 9:05 a.m. EDT (1305 GMT) as NASA officials proceed with the test, which is a key milestone in assessing the Space Launch System megarocket and Orion spacecraft for their readiness to perform a round-the-moon mission.

Jeremy Graeber, assistant launch director, told listeners on NASA Television that the gaseous nitrogen issue holding up tanking operations earlier in the morning EDT has been resolved. Both the gaseous nitrogen valve and the controller, which had been troublesome, are now working properly following previously disclosed engineering fixes.

"The team did a great job identifying the problem and resolving it, and so we're in really good shape," Graeber said. "That problem has been cleared and we're at a good configuration to pick up with cryo loading [and] no longer constrained."

Engineers have also picked up an issue with the left solid rocket booster, showing that the resistance was lower than expected, Graeber said. But given the consistent history of the booster's performance, the teams decided to proceed and not to declare it a constraint to the wet dress rehearsal.

The resistance test was showing a value of 22.4, compared to a nominal reading of between 24.4 and 37.4, Graeber said. 

"The value we're seeing now is consistent with what we've been seeing over the last several weeks," he added. "So although it is outside of our nominal range, we understand that it's consistently here. So we believe that's a valid number."

Weather is predicted to remain good for tanking operations despite T-0 (the simulated liftoff) being pushed back about two hours to 4:30 p.m. EDT (2030 GMT), Graeber added.

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NASA resets terminal countdown to 4:20 p.m. EDT

NASA expects to bring Artemis 1s wet dress rehearsal out of its extended hold at 9:20 a.m. EDT (1320 GMT) after engineers successfully addressed issues with a valve and automatic controller on a backup gaseous nitrogen system. 

As planned, the backup gaseous nitrogen system will now be swapped with the primary, meaning the backup will be used as the source to purge harmful gases throughout the tests, NASA's Derrol Nail said during a livestreamed update at 8:30 a.m. EDT (1230 GMT) on NASA Television.

Should the countdown go to plan, the terminal countdown will start at 4:20 p.m. EDT (2020 GMT) and conclude at 4:30 p.m. EDT, roughly two hours later than scheduled.

Weather is expected to hold into that period, Nail said. "Some showers could develop around the pad in the early afternoon, but they're expected to move west. Tanking, therefore, in the weather forecasts for taking is go," he added.

Backup gaseous nitrogen line troubleshooting continues

Artemis 1 wet dress rehearsal teams have successfully replaced a gaseous nitrogen valve on a backup line that forced an extension of a launch hold past 7:30 a.m. EDT (1130 GMT), NASA officials said during a live update at 8:00 a.m. EDT (1200 GMT).

"It would not close," NASA's Derrol Nail, a communications representative, said during a broadcast on NASA Television. "Not sure about what caused the failure at this time, but the teams have been working on it and have replaced the valve. The manual retest of that valve is working well, according to the team that's out there."

Teams are now focused on an automatic controller for the backup gaseous nitrogen line, performing tests to see if that will work properly, Nail said. Provided they get the controller working, engineers have also decided to move the troublesome gaseous nitrogen as the primary source for the rocket's test. (There are two sources; it was the redundant one causing issues, but the prime one was working just fine.)

"The launch team, meanwhile, has been moving forward configuring the launch vehicle for tanking," Nail continued. "They have cycled the valves for liquid oxygen tank in the upper stage, and then began proceeding with cycling the valves on the liquid oxygen stage."

NASA is providing updates approximately every half hour on its live broadcast (opens in new tab) as tanking operations continue for the wet dress rehearsal, which may take place later today (Monday) if all goes to plan. Exact rescheduled timing for testing procedures have not been released yet, as the troubleshooting is ongoing; the nominal plan had put the first expected terminal countdown at 2:30 p.m. EDT (1830 GMT).

NASA repairs backup valve for gaseous nitrogen

Engineers have repaired a valve for the backup gaseous nitrogen line, NASA's Exploration Ground Systems stated on Twitter at 7:45 a.m. EDT (1145 GMT).

"The launch team is assessing next steps and continue to be in an extended hold," agency officials tweeted. 

A planned hold during the wet dress rehearsal was supposed to conclude at 7:30 a.m. EDT (1130 GMT), but the backup supply issue forced a pause in returning to the countdown.

The primary supply of gaseous nitrogen, required to purge harmful gases from the Space Launch System megarocket during tanking, remains operational.

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NASA proceeds with tanking while working backup issue

NASA officials have decided to "press" towards tanking operations while attempting to address a backup supply issue of gaseous nitrogen in parallel, a live broadcast for the Artemis 1 wet dress rehearsal stated around 7:40 a.m. EDT (1140 GMT).

The primary supply for gaseous nitrogen is working well, but the backup remains at issue.

An update from engineering teams is expected in about 45 minutes on how operations are going, NASA communications official Derrol Nail said during the broadcast. He noted nitrogen is used to prevent buildup of gases, along with keeping avionics and electronics in the engine section dry, among other purposes. 

"Gaseous nitrogen is critical to get started with tanking," Nail said. 

NASA extends hold to examine backup nitrogen issue

NASA has extended its hold of the Artemis 1 tanking operations, which was supposed to conclude at 7:30 a.m. EDT (1130 GMT), due to an issue with a backup supply of gaseous nitrogen, the agency said on its broadcast.

"The primary supply is good. It's the backup supply issue for the controller for the supply valve, and so the launch team is currently working on that issue," Derrol Nail of NASA communications said during the live broadcast a few minutes ago.

"Until they do until find a resolution, the launch team has decided to hold off on cryo loading until they have a better understanding of what is required for that repair."

Problems with gaseous nitrogen supply, used to support activities at the pad, had delayed previous countdown rehearsals, although it was liquid hydrogen and liquid oxygen issues that ended up being the main issue during past tests. 

NASA recently upgraded its infrastructure at Pad 39B at the agency's Kennedy Space Center to increase storage facilities for gaseous nitrogen. Engineers performed this work ahead of schedule after Artemis 1 was rolled back to the Vehicle Assembly Building in April to address its tanking issues during previous rehearsals.

Nitrogen is used during testing, along with hydrogen, helium and air, in test stands provided by NASA's High Pressure Gas Facility, according to agency materials (opens in new tab). Gaseous nitrogen is used to purge oxygen from the SLS prior to fueling operations, for safety purposes, during wet dress and launch, NASA said during previous tests.

Under the nominal schedule (opens in new tab), the terminal countdown is supposed to proceed at 2:30 p.m. EDT (1830 GMT), but Nail said it is likely that countdown will be delayed due to the issue.

NASA begins Artemis 1 tanking livestream

NASA has just begun the livestream of the Artemis 1 tanking operations, in anticipation that the wet dress rehearsal will start later today (Monday, June 20). You can watch the livestream above, on NASA's YouTube channel and on NASA's website.

"We are good to go for tanking, in terms of the weather," the broadcast said (opens in new tab) at 7:12 a.m. EDT (1112 GMT). For example, the weather officer says probability of precipitation is 20%, and lightning is 10%. This forecast is valid until about 2:40 p.m. EDT (1840 GMT), agency officials said on the broadcast.

Updates will be provided every half-hour at the least during the broadcast, which will extend through much of Monday if operations go to plan. The agency said the launch team is working a "few issues", but provided no further detail as of 7:15 a.m. EDT (1115 GMT).

"The team powered up ICPS [interim cryogenic propulsion system] overnight, and just finished their morning prep meeting before we proceed with the test," said Jim Free, associate administrator for NASA's exploration systems development mission directorate, on Twitter (opens in new tab) at 6:52 a.m. EDT (1052 GMT).

Artemis 1 'go' for tanking operations Monday

Artemis 1 at NASA's Kennedy Space Center during the wet dress rehearsal on June 19, 2022.

(Image credit: NASA)

The Artemis 1 stack is "go" to proceed with the terminal countdown of the wet dress rehearsal on Monday (June 20), NASA officials said in a blog post (opens in new tab)

The countdown would allow the stacked Space Launch System rocket and Orion spacecraft to practice a launch on the ground prior to doing it for real, during a planned uncrewed round-the-moon test. 

"Teams are performing a pre-launch walkdown of the rocket to ensure the Space Launch System is prepared for the upcoming propellant loading operations," the blog post stated at 4:57 p.m. EDT (2157 GMT) on Sunday (June 19).

"Later today, they [teams] will configure mobile launcher and pad facility systems and structures, and power up the interim cryogenic propulsion stage," added the blog post, which was published following a routine mission management team meeting earlier in the afternoon EDT.

Favorable weather conditions are expected for the countdown, NASA noted. For tanking to proceed, there must be less than a 20% chance of lightning within 5 nautical miles (5.8 miles or 9.3 km) of Launch Pad 39B at NASA's Kennedy Space Center in Florida, where the rehearsal is taking place.

Additionally, winds must be lower than 37.5 knots (43.1 mph or 69.5 km/h) and the temperature must be above 41 degrees Fahrenheit (5 degrees Celsius), the agency stated.

Another mission management team meeting is expected Monday at 6 a.m. EDT (1000 GMT) "to assess operations and determine whether to proceed with tanking operations," NASA said. That milestone will be L-8 hours, 40 minutes in the countdown and the meeting will take place at the start of a planned 90-minute hold.

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Wet dress rehearsal 'on track' as second day of test approaches

The Artemis 1 stack during wet dress rehearsal operations, as seen on NASA's Twitter feed June 19, 2022.

(Image credit: NASA)

NASA says all Artemis 1 wet dress rehearsal operations are "on track" as the test approaches its second day of work later today, at 5 p.m. EDT (2200 GMT) Sunday.

NASA plans a routine mission management team meeting this afternoon EDT to review the status of rehearsal, the agency said in a blog post (opens in new tab) Sunday (June 19) at 10:48 a.m. EDT (1448 GMT). The wet dress rehearsal is a key step in getting Artemis 1 ready for its uncrewed round-the-moon test, which may launch later in 2022.

"Overnight, engineers powered up the Orion spacecraft and the Space Launch System's core stage," the agency stated in the blog post. "Teams also configured several systems on the ground, rocket, and spacecraft and performed activities to prepare umbilicals that connect the rocket and spacecraft to the mobile launcher and are used to provide power, communications, coolant, and propellant."

The Twitter feed for NASA's Kennedy Space Center, where the test is taking place at Launch Pad 39B, confirmed (opens in new tab) at 11:26 a.m. EDT (1526 GMT) that tanking operations remain scheduled for tomorrow (Monday, June 20).

The agency plans to provide live commentary Monday during tanking operations. In the meantime, NASA is streaming live video (opens in new tab) of the rocket and spacecraft.

Wet dress rehearsal begins at 5:30 p.m. EDT

A screenshot of the Artemis 1 stack during wet dress rehearsal preparations on June 18, 2022.

A screenshot of the Artemis 1 stack during wet dress rehearsal preparations on June 18, 2022. (Image credit: NASA Television)

NASA confirmed in a blog post (opens in new tab) that the countdown for the wet dress rehearsal for Artemis 1 began at 5:30 p.m. EDT (2130 GMT) on Saturday (June 18), exactly on schedule. 

The test will evaluate the stacked Artemis 1 system, meaning an Orion spacecraft and Space Launch System megarocket, in a simulated launch countdown test.

"Overnight, teams will power up the Orion spacecraft and the Space Launch System core stage and prepare the rocket’s four RS-25 engines, which will not be lit during the test," NASA said in the update, posted at 5:49 p.m. EDT (2149 GMT).

"Weather constraints for propellant loading operations planned for Monday stipulate there must be less than a 20 percent chance lightning within five nautical miles of pad during the first hour of tanking," the agency added. "Winds also must not be above 37.5 knots and the temperature cannot be below 41 degrees Fahrenheit [5 degrees Celsius.]"

NASA is continuing to provide live video (opens in new tab) of the rocket on the launch pad at the agency's Kennedy Space Center in Florida, although live commentary is not expected to begin until tanking operations commence on Monday (June 20).

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Wet dress rehearsal begins

A view of NASA's Artemis 1 SLS moon rocket on the launch pad on June 12, 2022 at dawn.

A view of NASA's Artemis 1 SLS moon rocket on the launch pad on June 12, 2022 at dawn. (Image credit: NASA TV)

NASA's wet dress rehearsal of its Space Launch System rocket is expected to begin about now, at 5 p.m. EDT (2100 GMT). Under NASA's plan (opens in new tab), the launch team will have their call to stations and the countdown will begin in one of the final major milestones before the moon-circling, uncrewed Artemis 1 can be cleared for launch.

NASA tried to perform the wet dress in early April, but had trouble fueling the SLS on three separate attempts. The Artemis stack was rolled back to KSC's Vehicle Assembly Building (VAB) in late April to address a hydrogen leak and other issues. The rocket is now back on the pad ready for a fresh try.

NASA is streaming live video (opens in new tab) of the rocket and spacecraft at Launch Pad 39B at the agency's Kennedy Space Center. Live commentary will be available on the agency’s website (opens in new tab) after tanking operations begin Monday (June 20).

The Artemis 1 stack — the SLS and an Orion crew capsule — will be vigorously tested over the next two days to assess its ability to perform a simulated launch countdown. NASA says (opens in new tab) these will be some of the milestones to look for:

Saturday, June 18, 5 p.m. EDT (2100 GMT) – L-45 hours, 40 minutes and counting 

  • The launch team arrives on their stations and the countdown begins (L-45, 40 minutes hours)
  • Fill the water tank for the sound suppression system (L-45 hours)
  • Orion spacecraft power up start (L-41 hours)
  • SLS core stage is powered up (L-35 hours, 20 minutes)
  • Final preparations of the four RS-25 engines complete (L-30 hours, 30 minutes)

Monday, June 20, 1:40 a.m. EDT (0540 GMT) – L-13 hours and counting 

  • The SLS interim cryogenic propulsion stage (ICPS) is powered up (L-12 hours, 50 minutes)
  • All non-essential personnel leave Launch Complex 39B (L-12 hours)

Monday, June 20, 6 a.m. EDT (1000 GMT) – L-8 hours, 40 minutes and counting

  • Built in countdown hold begins and lasts approximately 1.5 hours (L-8 hours, 40 minutes)
  • The launch director and mission management team chair conduct a weather and tanking briefing (L-8 hours, 20 minutes)
  • The launch director and mission management team chair decide if they are “go” or “no-go” to begin tanking the rocket (L-7 hours, 50 minutes)

Selected milestones after this point on Monday include:

  • 7:35 a.m. EDT / 1135 GMT: Core stage liquid oxygen (LOX) chilldown start (L-7 hours, 05 minutes)
  • 8:35 a.m. EDT /1235 GMT: Core stage liquid hydrogen (LH2) chilldown start (L-6 hours, 5 minutes)
  • 10:10 a.m. EDT / 1410 GMT: Core stage LH2 topping start (L-4 hours, 30 minutes)
  • 10:15 a.m. EDT / 1415 GMT: Core stage LH2 replenish start (L-4 hours 25 minutes)
  • 10:20 a.m. EDT / 1420 GMT: Orion communications system activation start (L-4 hours, 20 minutes)
  • 11:15 a.m. EDT / 1515 GMT: Core stage LOX topping start (L-3 hours, 25 minutes)
  • 11:40 a.m. EDT / 1540 GMT: ICPS/SLS telemetry data verified with Mission Control Center and SLS Engineering Support Center (L-3 hours)
  • 2 p.m. EDT / 1800 GMT:  L-40 minutes and holding; final NASA test director briefing begins.
  • 2:30 p.m. EDT / 1830 GMT: Wet Dress Rehearsal Run 1 begins
  • 2:41 p.m. EDT / 1841 GMT: Wet Dress Rehearsal Run 1 ends
  • 3:41 p.m. EDT / 1941 GMT (approximate): Wet Dress Rehearsal Run 2 begins
  • 3:52 p.m. EDT / 1952 GMT (approximate): Wet Dress Rehearsal Run 2 ends

Back on the launch pad

With wildflowers surrounding the view, NASA's Artemis 1 moon rocket — carried atop the agency's crawler-transporter 2 — arrives at Launch Pad 39B at the agency’s Kennedy Space Center in Florida on June 6, 2022.  (Image credit: NASA/Ben Smegelsky)

NASA's massive Artemis 1 rocket is back on the launch pad as of Monday (June 6) for a second try at what the agency calls a wet dress rehearsal. During that process, which will begin on June 19 and last about two days if all goes well, NASA personnel will fill the rocket and its launch infrastructure with more than 700,000 gallons (2.65 million liters) of cryogenic fuel, then conduct a series of countdown rehearsals, including practicing for holds and aborts.

This week's arrival marks the Artemis 1 rocket's second visit to launch pad 39B, after NASA attempted a wet dress rehearsal in April. Assuming the agency can complete the test, the rocket will roll back to the massive Vehicle Assembly Building one more time before launching on an uncrewed mission around the moon.

You can watch live footage of the rocket (opens in new tab) courtesy of NASA.

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Artemis 1's second rollout is underway

NASA's Artemis 1 moon mission stack rolls out from the Vehicle Assembly Building (VAB) at Kennedy Space Center (KSC) in Florida on June 6, 2022. Artemis 1 is headed for KSC's Pad 39B for a series of prelaunch tests known as a wet dress rehearsal. Artemis 1 first attempted the wet dress on April 1 but ran into some technical troubles and rolled back to the VAB for repair work.

NASA's Artemis 1 moon mission stack rolls out from the Vehicle Assembly Building (VAB) at Kennedy Space Center (KSC) in Florida on June 6, 2022. Artemis 1 is headed for KSC's Pad 39B for a series of prelaunch tests known as a wet dress rehearsal. Artemis 1 first attempted the wet dress on April 1 but ran into some technical troubles and eventually rolled back to the VAB for repair work. (Image credit: NASA's Exploration Ground Systems via Twitter)

NASA's Artemis 1 moon mission is on the move again. The Artemis 1 Space Launch System (SLS) rocket and Orion capsule left the Vehicle Assembly Building (VAB) at NASA's Kennedy Space Center (KSC) a little after midnight EDT (0400 GMT) on June 6, heading for KSC's Pad 39B. The roughly 4-mile (6.4 kilometers) trek is expected to take 8 to 12 hours. You can learn more in our rollout preview story.

Artemis 1 is headed to Pad 39B for a "wet dress rehearsal," a crucial series of tests that includes fueling of the SLS and the performance of several simulated launch countdowns. The 48-hour wet dress is expected to begin on June 19.

This is Artemis 1's second rollout ahead of a wet dress attempt. The stack first headed to Pad 39B in mid-March and initiated a wet dress on April 1. Artemis 1 ran into some technical troubles on that try, however, and rolled back to the VAB for maintenance work on April 25.

Artemis 1 stack rolls off launch pad

The Artemis 1 moon mission stack rolls off Pad 39B at NASA's Kennedy Space Center in Florida on April 25, 2022. Artemis 1 is headed to KSC's Vehicle Assembly Building, where team members will address a few issues identified during the mission's "wet dress rehearsal" test in early April.

The Artemis 1 moon mission stack rolls off Pad 39B at NASA's Kennedy Space Center in Florida on April 25, 2022. Artemis 1 is headed to KSC's Vehicle Assembly Building, where team members will address a few issues identified during the mission's "wet dress rehearsal" test in early April. (Image credit: Kennedy Space Center via Twitter)

NASA began rolling its Artemis 1 moon mission off Pad 39B at NASA's Kennedy Space Center (KSC) in Florida this afternoon (April 25). The Space Launch System rocket and Orion capsule that will fly Artemis 1 are on their way back to KSC's Vehicle Assembly Building, where team members will address a few issues identified during the Artemis 1 "wet dress rehearsal" earlier this month. 

The 4-mile (6.4 kilometers) journey to the VAB is expected to take 8 to 12 hours, NASA officials said (opens in new tab).

NASA halts 3rd attempt at fueling Artemis 1 moon rocket

NASA's Artemis 1 Space Launch System moon rocket stands atop Launch Pad 39B at the Kennedy Space Center in Cape Canaveral, Florida during a fueling test on April 4, 2022.

NASA's Artemis 1 Space Launch System moon rocket stands atop Launch Pad 39B at the Kennedy Space Center in Cape Canaveral, Florida during a fueling test on April 4, 2022. (Image credit: NASA/Joel Kowsky)

NASA did not finish fueling the core stage of the Artemis 1 moon mission's Space Launch System (SLS) rocket as planned today (April 14), calling it off after noticing a leak of liquid hydrogen. Read our full story here.

It was the agency's third attempt at SLS propellant loading, one of the most important parts of the Artemis 1 prelaunch "wet dress rehearsal." Technical issues scuttled the first two tries as well. It's unclear when the Artemis 1 team will resume the multi-day test, and which procedures they still want to do; we'll have to stay tuned for updates, which NASA officials said will be coming shortly.

NASA pauses fueling of Artemis 1 moon rocket

NASA has paused the fueling of the Artemis 1 mission's Space Launch System (SLS) rocket after encountering an issue during a "fast fill" of liquid hydrogen, or LH2.

"After fast fill on LH2 began, a surge in pressure automatically stopped the flow of liquid hydrogen," agency officials wrote in an update (opens in new tab) at 2:10 p.m. EDT (1810 GMT) today (April 14). "Teams are working to troubleshoot this issue and the rocket is in a safe configuration. In the meantime, liquid oxygen flow was paused on the core stage to ensure the tanking operations for LOX and LH2 remain synchronized."

LOX, or liquid oxygen, is the other propellant for the SLS.

These operations are part of the Artemis 1 wet dress rehearsal, a crucial series of prelaunch tests that began on Tuesday (April 12) and are slated to wrap up this afternoon. Keep checking back here for more updates about the test.

Fueling underway for Artemis 1 moon rocket

NASA is proceeding with liquid oxygen fueling of the Artemis 1 moon rocket after temperature readings slowed their work earlier today. 

"After troubleshooting an issue with the temperature of liquid oxygen during early stages of propellant loading into the rocket’s core stage, launch controllers have resumed operations," NASA wrote in an update (opens in new tab) at 12:25 pm ET. "Teams performed chill down operations again before liquid oxygen began flowing into the tank and adjusted pump speeds as necessary during flow to help ensure temperatures remain below limits. They also opened valves to bleed off any warm liquid oxygen."

NASA has also begun filling the Artemis 1 core stage with the super-cold liquid hydrogen propellant the rocket will use, in all, Artemis 1's Space Launch System rocket will use 537,000 gallons of propellant during its launch to the moon. -- Tariq Malik

Artemis 1 moon mission test runs into oxygen snag

NASA has continued its work testing hardware that will fly on the uncrewed Artemis 1 mission later this year. This morning, mission personnel worked to cool oxygen lines in preparation for fuel loading, but as liquid oxygen began flowing into the rocket, teams noticed that the temperature had crept too high and paused the test, which had been targeting a "launch (opens in new tab)" time of 3:57 p.m. EDT (1957 GMT).

"As teams began the liquid oxygen (LOX) slow fill, a temperature limit was exceeded," Jeremy Parsons, deputy manager of the Exploration Ground Systems team at Kennedy Space Center, wrote in a tweet (opens in new tab). "Teams believe they understand the issue and are working a solution that will allow operations to resume. These are all important aspects of test conditions in complex environments."

NASA powers up Artemis 1 rocket's core stage, Orion spacecraft

Artemis 1 sits atop Launch Complex 39B on March 18, 2022, following its hours-long rollout.

(Image credit: NASA/Joel Kowsky)

Overnight from Tuesday to Wednesday (April 12 to April 13), the Artemis 1 team powered up the core stage of the mission's huge Space Launch System rocket as well as its Orion spacecraft, NASA officials wrote in an update Wednesday (opens in new tab).

This work is part of the Artemis 1 "wet dress rehearsal," a practice run of critical prelaunch procedures such as rocket fueling. The team remains on track to fill the tanks of the SLS core stage (but not the upper stage) on Thursday (April 14), as planned, agency officials said.

The wet dress is scheduled to wrap up on Thursday. If everything goes well, the Artemis 1 team will then proceed toward gearing up for the mission, which will launch an uncrewed Orion on a journey around the moon, perhaps as early as June.

NASA resumes Artemis 1 moon mission's wet dress rehearsal

The moon glows behind the Space Launch System of Artemis 1 on March 17, 2022.

(Image credit: NASA/Aubrey Gemignani)

NASA has resumed a key prelaunch test of its Artemis 1 moon mission.

The Artemis 1 wet dress rehearsal began once again at about 5 p.m. EDT (2100 GMT) on Tuesday (April 12), when team members arrived at their stations at the Launch Control Center at NASA's Kennedy Space Center (KSC) in Florida.

The wet dress will unfold over the next 48 hours, with the big events — fueling of the core stage of Artemis 1's huge Space Launch System rocket, for example, and the performance of several simulated countdowns — occurring on Thursday (April 12). 

The weather looks good for tanking operations on Thursday, NASA officials wrote in a blog post on Tuesday (opens in new tab)

This isn't the first attempt at Artemis 1's wet dress. NASA began the test on April 1 and aimed to finish it on April 3, but technical issues and the April 8 launch of the private Ax-1 astronaut mission pushed things back to Tuesday. 

One of the technical issues, a faulty valve on the Artemis 1 mobile launch tower, led to the modification of some wet dress procedures. NASA had originally intended to fuel up both stages of the SLS, for example, but will now focus on tanking just the core stage. Read more in our story here (opens in new tab).

NASA resuming Artemis 1 moon rocket test Tuesday

NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard is seen atop a mobile launcher at Launch Complex 39B, Sunday, April 3, 2022, as the Artemis I launch team conducts the wet dress rehearsal test at NASA’s Kennedy Space Center in Florida.

(Image credit: NASA/Joel Kowsky)

NASA plans to resume the crucial "wet dress rehearsal" of its Artemis 1 moon mission Tuesday (April 12) after a more than weeklong delay.

The test — a practice run of the most important Artemis 1 prelaunch activities, including rocket fueling — began on April 1 and was supposed to wrap up 48 hours later. Technical issues pushed things back a few days, however, and the team then had to stand down for the launch of the Ax-1 private astronaut mission, which lifted off Friday (April 8) from a neighboring launch pad at NASA's Kennedy Space Center in Florida.

But the wet dress is slated to pick up again Tuesday with a "call to stations" at 5 p.m. EDT (2100 GMT). The big-ticket items, including fueling of Artemis 1's huge Space Launch System (SLS) rocket, will occur Thursday (April 14), if all goes according to plan.

Only the core stage of the two-stage SLS will be fueled, however. The original plan called for fueling the upper stage as well, but NASA nixed that part after discovering a problem with a valve on Artemis 1's mobile launch tower. Read our full story here.

Artemis is back to work on Saturday

A view of the Artemis 1 rocket on the launch pad before a "wet dress rehearsal" to prepare for launch. (Image credit: NASA)

NASA has announced that it will resume work on the Artemis 1 wet dress rehearsal, a crucial pre-flight test for the uncrewed moon-circling mission due to launch this summer. The agency began wet dress rehearsal activities on April 1, but had to stop procedures twice. Then, NASA personnel stood down from the rehearsal in order to permit the Ax-1 mission to the International Space Station to launch on Friday (April 8).

Now, NASA has a plan to get back to work on the rocket check. Agency personnel will begin work on Saturday (April 9) at about 5 p.m. EDT (2100 GMT). The Artemis 1 team will work through each task of launch preparations, straight through to just under 10 seconds before what would be launch time on a real flight. If all goes well, the team will reach that "T-0" time on Monday (April 11) at about 2:40 p.m. EDT (1840 GMT), NASA officials wrote in a statement (opens in new tab).

NASA halts fueling of Artemis 1 moon rocket due to valve issue

The "wet dress rehearsal" of NASA's Artemis 1 moon mission has hit another snag.

The crucial three-day test was supposed to wrap up Sunday (April 3) with the fueling of Artemis 1's huge Space Launch System (SLS) rocket, but a problem with the fans on its mobile launch tower pushed things back to Monday (April 4). The Artemis 1 team began loading 700,000 gallons of supercold liquid propellants into the rocket on Monday but had to halt after discovering a problem with a vent valve on the mobile launcher.

"Due the vent valve issue, the launch director has called off the test for the day. The team is preparing to offload LOX and will begin discussing how quickly the vehicle can be turned around for the next attempt. A lot of great learning and progress today," NASA's Exploration Ground Systems program said via Twitter Monday afternoon (opens in new tab). ("LOX" is liquid oxygen, one of the two SLS propellants. The other is liquid hydrogen.)

Stay tuned for more updates.

NASA sets new Artemis 1 "launch" time of 6:02 p.m. EDT

NASA has set a new "launch" time for its Artemis 1 moon mission — 6:02 p.m. EDT (2202 GMT) today (April 4).

The huge Space Launch System (SLS) rocket and Orion capsule that will fly Artemis 1 won't actually get off the ground today, of course; NASA is currently conducting a "wet dress rehearsal" that simulates many of the activities leading up to launch, including fueling of the SLS. This crucial trial started on Friday afternoon (April 1) and was supposed to wrap up on Sunday (April 3), but several technical issues pushed some work to today. 

Keep checking back here for updates. And you can see live video of the SLS-Orion stack on the launch pad at NASA's Kennedy Space Center here (opens in new tab).

NASA 'go' to fuel Artemis 1 moon rocket

NASA launch controllers cleared the Artemis 1` moon rocket to proceed with "tanking" (or fueling) the Space Launch System booster today at 7:40 a.m. EDT (1140 GMT). Later, officials are expected to give a "go" to actually start the fueling process. 

NASA reports that the test team is in a hold currently as they work to resolve an outage with a vendor that provides gaseous nitrogen that is needed for the tanking process.

"Nitrogen is used to prepare for, and during tanking operations, to provide a non-flammable environment inside of the SLS. When the issue is resolved, the countdown clock will pick back up with T-6 hours, 40 minutes on the clock (L-7 hours, 20 minutes) remaining in the countdown, (opens in new tab) beginning with chilling down the liquid oxygen lines for the core stage," NASA wrote in an update (opens in new tab)

Earlier, NASA was targeting a planned T-0 "launch time" of 2:40 p.m. EDT (1840 GMT) in which to conclude today's test. We're awaiting word from NASA if that time will change. 

NASA to try Artemis 1 fueling test again

NASA will make a second attempt to fuel the Artemis 1 Space Launch System moon rocket today after a ground systems equipment problem on the rocket's mobile launcher prevented the test on Sunday (April 3).

The Artemis 1 moon rocket is standing atop Pad 39B of NASA's Kennedy Space Center in Cape Canaveral, Florida, where it has been undergoing a critical "wet dress rehearsal" to practice a full launch countdown ahead of its moon mission later this year. 

At 6 a.m. EDT (1000 GMT), the launch control team was expected to meet and review the rocket's status before deciding whether to begin loading fuel at around 7 a.m. EDT (1100 GMT). If approved, the team would then proceed to fuel the SLS rocket with the 700,000 gallons of super-cold liquid oxygen and liquid hydrogen. 

NASA plans to countdown to a T-0 "liftoff" time of 2:40 p.m. EDT (1840 GMT). 

Scrub! NASA calls off Artemis 1 fueling test

NASA has called off its planned "wet dress rehearsal" fueling test of its first Artemis 1 moon rocket over safety concerns with the rocket's mobile launch platform. 

NASA announced the scrub on Twitter at 12:06 p.m. EDT (1606 GMT), nearly five hours after fueling was originally scheduled to occur. The reason, NASA officials said, was a pressurization problem on the mobile launcher that houses ground crew systems. 

"Teams have decided to scrub tanking operations for the wet dress rehearsal due to loss of ability to pressurize the mobile launcher. The fans are needed to provide positive pressure to the enclosed areas within the mobile launcher and keep out hazardous gases," NASA wrote in an update today. "Technicians are unable to safely proceed with loading the propellants into the rocket’s core stage and interim cryogenic propulsion stage without this capability."

NASA is now working to determine if ground crews can make another attempt to fuel the Artemis 1 mission's Space Launch System rocket on Monday, April 4. 

A media briefing on NASA's plans is expected later today.

Fueling day for Artemis 1 moon rocket

NASA's Artemis 1 Space Launch System moon rocket stands atop Launch Pad 39B at the Kennedy Space Center in Cape Canaveral, Florida during a fueling test on April 3, 2022.

NASA's Artemis 1 Space Launch System moon rocket stands atop Launch Pad 39B at the Kennedy Space Center in Cape Canaveral, Florida during a fueling test on April 3, 2022. (Image credit: NASA Kennedy Space Center)

It's fueling day for NASA's Artemis 1 moon rocket as the agency nears the main event of its "wet dress rehearsal." 

At 6:45 a.m. EDT today, NASA's Artemis 1 launch director gave the "go" to begin fueling the Artemis 1 Space Launch System rocket at 7:20 a.m. EDT (1120 GMT). 

Strong storms overnight caused about an hour of delays for crews working at Launch Pad 39B, according to Jeremy Parsons, NASA's deputy manager of the Exploration Ground Systems, who is live Tweeting the test.

Four lightning strikes occurred in the vicinity of the Pad 39B site, including the strongest strike to the pad's protective catenary wire and tower structure designed to shield the Artemis 1 moon rocket from direct lightning hits. 

"1 of the strikes last night was the strongest we have seen since we installed the new lightning protection system," Parsons wrote. "It hit the catenary wire that runs between the 3 towers. System performed extremely well & kept SLS and Orion safe. Glad we enhanced protection since Shuttle!"

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Artemis 1 SLS rocket core stage powered up for test

NASA's three-day launch countdown and fueling test for its Artemis 1 moon rocket is in full swing, with engineers powering up the Space Launch System's core stage at 3 a.m. EDT (0700 GMT) this morning, NASA reports. 

The test, called a "wet dress rehearsal," is practicing launch countdown and fueling procedures for the Space Launch System rocket that will be needed when NASA launches the actual Artemis 1 moon mission with this booster around late May or June. 

You can see live views of the Artemis 1 Space Launch System on the launch pad at NASA's Kennedy Newsroom YouTube Channel, which is embedded above.

The sun rises behind NASA's Artemis 1 moon rocket at Pad 39B of the Kennedy Space Center in Cape Canaveral, Florida. (Image credit: NASA)

Here's what NASA has on tap for today: "Around 3 a.m. on Saturday April 2, at approximately L-35 hours and 20 minutes, the Artemis I launch control team powered up the Space Launch System rocket’s core stage (opens in new tab), which will be loaded with more than 700,000 gallons of propellants during the tanking phase of the countdown (opens in new tab). During the day, teams will charge Orion flight batteries, conduct final preparations on umbilical arms, and conduct a final pre-launch walkdown," the agency wrote in a status update (opens in new tab).

At 10 a.m. EDT (1400 GMT), NASA will conduct a weather briefing, at which time the agency will release a new update. Jeremy Parsons, NASA's deputy manager of the Exploration Ground Systems program at @NASAKennedy (opens in new tab), is providing live updates via the agency's NASA Exploration Ground Systems Twitter account. -- Tariq Malik

Artemis 1 wet dress rehearsal press conference

NASA will hold a teleconference today at 1 p.m. EDT (1700 GMT) to discuss the agency's critical first fueling test for the Artemis 1 moon rocket currently standing atop Launch Pad 39B at the Kennedy Space Center in Florida. You can watch it live at the top of our homepage.

Called a "wet dress rehearsal," the multi-day test will begin on April 1 and end on April 3 and serve as a launch day dress rehearsal for NASA's Artemis 1 uncrewed moon mission. Artemis 1 is scheduled to launch no earlier than late May or early June. 

Speaking in today's conference will be:

  • Tom Whitmeyer, deputy associate administrator for common exploration systems development, NASA Headquarters in Washington
  • Charlie Blackwell-Thompson, Artemis launch director, NASA Exploration Ground Systems program, NASA Kennedy
  • John Honeycutt, manager, Space Launch System program, NASA’s Marshall Space Flight Center in Huntsville, Alabama
  • Howard Hu, manager, Orion program, NASA’s Johnson Space Center in Houston
  • Mike Sarafin, Artemis mission manager, NASA Headquarters

Tune in at 1 p.m. EDT to find out more about NASA's Artemis 1 fueling test plans.

There's a rocket there, we promise!

An early-morning view of the Artemis 1 rocket on the launch pad taken on March 18, 2022, by Space.com senior writer Chelsea Gohd. (Image credit: Future/Chelsea Gohd)

Space.com senior writer Chelsea Gohd is on the scene in foggy early-morning Florida checking out the Artemis 1 rocket on the launch pad. She's live-tweeting the visit so follow along to hear all the latest and see tons more photos:

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NASA's Artemis 1 megarocket is on the launch pad

NASA's Artemis 1 Space Launch System (SLS) rocket and Orion capsule at historic Launch Complex 39B at Kennedy Space Center, Florida. (Image credit: NASA/Joel Kowsky)

It's a milestone space fans have been waiting for for ages: NASA's first Space Launch System (SLS) rocket reached the launch pad in the early morning of Friday (March 18). The rocket will undergo about a month of testing, retreat to the Vehicle Assembly Building, roll out again and launch no earlier than late May.

NASA chief Bill Nelson speaks during Artemis rollout

NASA Administrator Bill Nelson speaks at the Artemis 1 rollout at the agency's Kennedy Space Center in Florida on March 17, 2022.

(Image credit: NASA TV)

The Artemis 1 rollout featured an appearance by NASA Administrator Bill Nelson, who gave a 13-minute speech as the agency's Space Launch System megarocket and Orion capsule rolled slowly by in the background. 

"Ladies and gentlemen, the world's most powerful rocket ever right here," Nelson said. "It's back to the moon and then on to Mars!"

Artemis 1 clears the VAB!

The Space Launch System rocket and Orion capsule that will launch on NASA's Artemis 1 moon mission emerge from the Vehicle Assembly Building at NASA's Kennedy Space Center during their rollout on March 17, 2022.

(Image credit: NASA TV)

The Space Launch System (SLS) rocket and Orion capsule that will fly NASA's Artemis 1 moon mission this summer emerge from the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida on March 17, 2022. The SLS-Orion duo are on their way to the launch pad for testing, a 4-mile (6.4 kilometers) journey that's expected to take 11 hours. Read more.

Rollout has begun!

The Space Launch System rocket and Orion capsule that will fly NASA's Artemis-1 moon mission begin their 4-mile (6.4 kilometers) rollout to the launch pad for testing on March 17, 2022 at NASA's Kennedy Space Center in Florida.

(Image credit: NASA TV)

NASA began rolling its Artemis 1 moon mission out to the launch pad at Kennedy Space Center in Florida today (March 17) at 5:47 p.m. EDT (2147 GMT). The agency's crawler-transporter 2 vehicle is carrying the Space Launch System rocket and Orion capsule on a 4-mile (6.4 kilometers) journey that's expected to take about 11 hours. Read more here.

Artemis 1 rollout is live!

NASA TV has begun livestreaming the rollout of its Artemis 1 moon mission to the launch pad at Florida's Kennedy Space Center for testing. Watch it live and read more here.

NASA opens VAB doors for Artemis 1 rollout

The mobile launcher with NASA’s Space Launch System (SLS) rocket and Orion spacecraft aboard is seen inside the Vehicle Assembly Building during the opening of the doors to High Bay 3 before rolling out to Launch Complex 39B for the first time, Thursday, March 17, 2022, at NASA’s Kennedy Space Center in Florida.

The mobile launcher with NASA’s Space Launch System (SLS) rocket and Orion spacecraft aboard is seen inside the Vehicle Assembly Building during the opening of the doors to High Bay 3 before rolling out to Launch Complex 39B for the first time, Thursday, March 17, 2022, at NASA’s Kennedy Space Center in Florida.  (Image credit: NASA/Keegan Barber)

NASA has opened the massive bay doors on the Vehicle Assembly Building to begin today's planned rollout of the first Space Launch System megarocket that will be used to launch the Artemis 1 mission to the moon. Rollout will begin at 5 p.m. EDT (2100 GMT). 

Space.com Senior Writer Chelsea Gohd is at NASA's Kennedy Space Center in Cape Canaveral, Florida where she is covering the rollout live. Here's some of her photos so far. 

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It's rollout day for Artemis 1 moon rocket!

It's finally here: rollout day for NASA's Artemis 1 moon rocket.  

As Space.com Senior Writer Chelsea Gohd reports, NASA's first Space Launch System megarocket will roll to Launch Pad 39B at the Kennedy Space Center in Florida at 5 p.m. EDT (2100 GMT). You'll be able to watch it live at start time on this page and on the Space.com homepage, courtesy of NASA TV. It will take up to 12 hours to reach the pad. Gohd is at the Kennedy Space Center and will cover the rollout overnight for Space.com. 

The Artemis 1 mission will launch an uncrewed Orion spacecraft around the moon no earlier than late May 2022. Today's rollout is a debut of sorts for the rocket and will kick off a month of pad tests that, NASA hopes, will include a "wet dress rehearsal" to fuel the rocket for the first time.

Today's rollout marks the biggest move in years for NASA's massive crawler carrier vehicle as well. The Apollo-era vehicle, originally built to move Saturn V rockets, weighs 5.75 million pounds (2.60 million kilograms) and was used to move NASA space shuttles and the Ares I-X test rocket to the pad. 

Space.com's Spaceflight Editor Mike Wall has this explainer of the crawler carrier vehicle.

Artemis 1 rollout media teleconference today

Today (March 14), NASA will be hosting a live media teleconference discussing the details of the upcoming rollout of the Artemis 1 vehicles.

Rollout of the vehicles, the Space Launch System (SLS) megarocket and the Orion spacecraft, will take place on Thursday (March 17) at NASA's Kennedy Space Center in Florida. The pair will be carried by the agency's crawler-transporter 2 vehicle on a slow, 4-mile journey to Launch Pad 39B. 

Join the media teleconference (opens in new tab)live today at 5:30 EST (2230 GMT) at Space.com or directly via the agency's Youtube channel. You can watch the event live at the video above.

Send your name around the moon on Artemis 1

You can send your name around the moon on NASA's Artemis 1 mission, an uncrewed flight that's scheduled to launch in May or June. Just sign up for a free "boarding pass" at this NASA page (opens in new tab) — that's all there is to it! Read more here.

Artemis 1 rocket rollout set for March 17 for May launch

A close-up view of NASA's Artemis 1 Space Launch System megarocket inside the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida on Sept. 20, 2021.

A close-up view of NASA's Artemis 1 Space Launch System megarocket inside the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida on Sept. 20, 2021. (Image credit: NASA/Frank Michaux)

In a press conference today, NASA announced that it will roll out the Artemis 1 moon rocket, the agency's first Space Launch System megarocket, on March 17 at the Kennedy Space Center in a major milestone for the agency's return to the moon. 

Artemis 1 will roll out to Launch Pad 39B at the Kennedy Space Center for up to a month of pad tests and a "wet dress rehearsal" in which the rocket will be fueled as if for launch. The tests will set the stage for an Artemis 1 launch sometime in May 2022, but that could slip to June or July, NASA officials said today. 

You can read the full story, including details on the wet dress rehearsal, rollout and launch window plans, in our wrap story by Mike Wall.

NASA Artemis 1 mission update today

Update for 1:30 pm ET: NASA is now targeting 2:30 p.m. EST (1930 GMT) for its press teleconference today on the Artemis 1 moon mission update.


NASA will hold a live teleconference today to discuss its plans to launch the Artemis 1 moon mission as early as April. The teleconference will begin at 1:30 pm ET (2030 GMT) today and you can listen in live here. 

Artemis 1 is NASA's first mission to the moon under the agency's Artemis program, which aims to send astronauts to the moon by around 2025 or so. That crewed moon landing will occur on the Artemis 3 mission. 

As the first to fly, Artemis 1 will not carry a crew, but will fly on a trip around the moon with instruments, cubesats and more aboard. The mission will use the new Space Launch System to launch an Orion space capsule to the moon and back. 

The rollout of that SLS moon rocket is expected sometime in March, with NASA due to give an update on that process today.

NASA fires up Artemis 1 moon rocket's first-stage engines again

NASA's Space Launch System rocket being readied for a roll-out ahead of its test flight to the moon later this year.

NASA's Space Launch System rocket being readied for rollout ahead of its test flight to the moon later this year. (Image credit: NASA)

NASA appears to have ironed out the kinks with the core-stage engines of the Space Launch System (SLS) rocket that will launch the Artemis 1 moon mission this spring.

A faulty controller on one of the SLS core-stage engines required some troubleshooting recently, pushing the launch of Artemis 1 — an uncrewed journey around the moon — back to April. Those fixes appeared to work, for the SLS core stage engines performed as expected during a recent series of tests, NASA officials announced on Friday (Feb. 18). Read our story about these developments here.

And speaking of developments: We're going to get another Artemis 1 update soon. NASA will hold a media teleconference on Thursday (Feb. 24) at 1:30 p.m. EST (1830 GMT) to discuss the latest progress toward launch. You can listen to it live Thursday here at Space.com, courtesy of NASA, or directly via the space agency.

Artemis 1 rollout delayed, NASA says

The Orion spacecraft for NASA’s Artemis I mission, fully assembled with its launch abort system, is lifted above the Space Launch System (SLS) rocket in High Bay 3 of the Vehicle Assembly Building at Kennedy Space Center in Florida on Oct. 20, 2021. (Image credit: NASA/Frank Michaux)

NASA's first Artemis moon mission will launch a little later than expected.

Today (Feb. 2), NASA announced that the rollout of its Space Launch System (SLS) megarocket and Orion capsule will be pushed from February to March, though the agency has yet to announce an exact date. 

"Ultimately, we're going to launch this flight hardware when the flight hardware is ready and when the team's ready," Mike Bolger, the program manager of exploration ground systems at NASA's Kennedy Space Center, told Space.com during a news conference held today.

While the exact rollout date and new launch date have not yet been announced, Mike Sarafin, the Artemis 1 mission manager at NASA Headquarters, said during the news conference that if the launch is pushed to April or May, a launch window would extend from April 8 to April 23; another would open May 7 and close May 21.

Learn more at Space.com here.

Artemis 1 status briefing starts soon

NASA officials are holding a news conference today (Feb. 2) at 12 p.m. EST (1700 GMT) to discuss the delayed rollout of the SLS rocket. You can listen to the teleconference live in the window above, courtesy of NASA. 

"While the teams are not working any major issues, NASA has added additional time to complete closeout activities inside the VAB [Vehicle Assembly Building] prior to rolling the rocket out for the first time," agency officials wrote in a statement (opens in new tab).

Full story: NASA delays rollout of Artemis 1 moon mission's SLS megarocket until March. Hear why today.