At 23:35 UTC on Dec. 16, 1972, the Apollo 17 command module, America, successfully completed its trans-Earth injection burn, sending it and its crew of NASA astronauts Gene Cernan, Harrison Schmitt, and Ronald Evans on a return trajectory back to Earth. The moment marked the final time a crewed Apollo spacecraft was in orbit around the Moon, and since that moment, no crewed spacecraft has ever ventured to the Moon’s vicinity.
Now, 52 years, three months, and 16 days after that moment, humanity is poised to return to the Moon.
NASA’s Artemis II mission, the first crewed mission under the agency’s Artemis lunar exploration program, is scheduled to launch from Launch Complex 39B (LC-39B) at the Kennedy Space Center (KSC) in Florida on Wednesday, April 1, at 6:24 PM EDT (22:24 UTC). The Orion CM-003 spacecraft, named Integrity by its four-person crew, will ride atop the Space Launch System (SLS) rocket, following an eastern trajectory out of Florida.
Artemis II will initially be injected into a high-Earth orbit for systems checks before performing a trans-lunar injection (TLI) burn to travel out to the Moon.
Orion’s TLI burn will place the spacecraft on a 10-day free-return trajectory around the Moon, bringing it within 6,513 km of the lunar far side at closest approach. Unlike NASA’s Apollo missions from the 1960s and 1970s, however, Artemis II will not enter orbit around the Moon; instead, it will perform a flyby that will see the spacecraft travel farther than the Moon’s orbit. At its farthest point from Earth, or apogee, Integrity will be approximately 7,600 km from Earth, where the crew will set the record for the farthest any humans have ever traveled from our home planet.
The Artemis II crew comprises three NASA astronauts and a single Canadian Space Agency (CSA) astronaut. NASA astronaut Reid Wiseman will command the mission, with NASA astronaut Victor Glover serving as pilot. Artemis II’s two mission specialists are NASA astronaut Christina Koch and CSA astronaut Jeremy Hansen. The mission will mark many astronaut firsts, with Glover becoming the first person of color, Koch becoming the first woman, and Hansen becoming the first non-American to travel beyond low-Earth orbit.
Artemis II will serve as the second flight of the Artemis program, the second launch of the SLS rocket, the third flight of the Orion spacecraft, and the first crewed mission of the Artemis program. Following recent updates to program timelines, the next Artemis mission, Artemis III, will test Orion’s docking systems and the selected Human Landing System (HLS) landers in low-Earth orbit in 2027.
Once these systems are validated, NASA is aiming to land at the Moon’s south pole on Artemis IV and Artemis V in 2028, with Artemis IV marking the first crewed landing on the Moon’s surface since Apollo 17.
History of the Artemis program
Following the end of the Apollo program in the early 1970s, NASA shifted its focus to low-Earth orbit with the Space Shuttle Program in 1972. Over the next 39 years, five Shuttle orbiters and 135 Space Shuttle missions would launch into low-Earth orbit, deploying various payloads, servicing the Hubble Space Telescope, and — most notably — constructing the International Space Station (ISS).
With the failure of the STS-107 mission in 2003, NASA planned to retire the Space Shuttle by 2010, and work on NASA’s next program commenced. The NASA Authorization Act of 2005 formalized NASA’s Constellation program, which was developed from the Vision for Space Exploration plan led by then-NASA Administrator Sean O’Keefe and President George Bush. Under the new legislation, NASA was directed to return to the Moon and develop a lasting presence that would ultimately allow for further exploration of our solar system, most notably of Mars.
Under the Constellation program, NASA would develop two new launch systems and a new crewed spacecraft to replace the Space Shuttle, as well as a lunar landing system. The two new launch systems were later revealed to be the Ares I and Ares V rockets, both of which would utilize hardware from the Space Shuttle program. The Ares I would launch the Orion spacecraft, while the larger Ares V would launch cargo, including the Altair lunar lander.
After Constellation suffered significant underfunding and long development times, President Obama’s Augustine Committee placed the program on hold in 2009. In October 2010, the NASA Authorization Act of 2010 canceled the program, keeping only the Orion spacecraft and directing NASA to develop the new SLS rocket for missions to the Moon.
Ares I-X launches from LC-39B in 2009, marking the only launch of the Constellation program. (Credit: NASA)
Development of SLS and Orion continued for the next several years, with a stripped-down version of Orion being launched on the Exploration Flight Test 1 (EFT-1) mission on a Delta IV Heavy in December 2014. Three years later, in December 2017, Space Policy Directive 1 was signed by President Trump, directing NASA to establish a new lunar exploration program that would utilize Orion, SLS, and commercial partners. SLS would serve as the primary launch vehicle for Orion, while commercial partners would launch various Artemis payloads, including the HLS landers for lunar landing missions.
In May 2019, following the announcement that program timelines would be accelerated to ensure a 2024 landing, NASA announced the program would be called Artemis, the Greek goddess of the Moon and twin sister of Apollo. Issues with funding and the worldwide COVID pandemic would further delay timelines for the program’s first missions.
Artemis I, an uncrewed test flight of Orion and the first launch of SLS, lifted off from LC-39B on Nov. 16, 2022. During the 25-day mission, Orion CM-002 entered a distant retrograde orbit around the Moon and completed two lunar flybys. The mission certified both SLS and Orion for subsequent crewed missions to the Moon, most notably Orion’s heat shield during reentry.
SLS and Orion launch from LC-39B on Artemis I. (Credit: Michael Baylor for NSF)
Artemis II development and pre-launch milestones
With Artemis I completed, NASA continued development on Artemis II. According to Space Policy Directive 1 issued in 2017, Artemis II was originally designated Exploration Mission 2 (EM-2) and would have launched to a lunar orbit atop the now-canceled SLS Block 1B rocket, then rendezvoused with an asteroid redirected by the uncrewed Asteroid Redirect Mission (ARM).
Following the cancellation of ARM in April 2017, NASA explored two proposals for EM-2; the first would see Orion and a four-person crew travel on a free return trajectory around the Moon, while the second would see Orion and a four-person crew deliver the first module of the now-canceled Lunar Gateway space station to lunar orbit.
Ultimately, NASA decided to enlist a commercial launch provider for the first Lunar Gateway module, and EM-2, later renamed Artemis II, was set to be a multi-week mission that would send a crewed Orion on a free-return trajectory around the Moon in 2019.
Following the completion of Artemis I in December 2022, much of Artemis II’s mission architecture was still under construction. The SLS core stage for Artemis II was rotated to horizontal and installed with its engine section in early 2023. By September 2023, the core stage’s four RS-25 engines — E2047, E2059, E2062, and E2063 — were installed. In April 2025, E2063 was swapped with E2061 due to an oxygen leak.
Closeup of Artemis II’s main engines during the core stage’s integration with the solid rocket boosters. (Credit: NASA)
On April 3, 2023, then-NASA Administrator Bill Nelson announced the four-person crew for Artemis II during a speech at Ellington Field in Houston, Texas. As the crew began training, development of the core stage and the rest of the Artemis II stack continued, with the core stage being delivered to KSC in mid-July 2024.
After several delays due to investigations into Orion’s heat shield and life support systems, Artemis II officially began stacking on Mobile Launcher 1 (ML-1) on Nov. 20, 2024. The Interim Cryogenic Propulsion Stage (ICPS) upper stage was delivered to Florida in March 2025, while Orion Integrity, complete with its European Service Module (ESM) from the European Space Agency (ESA), was delivered to KSC in May 2025. Following these deliveries and their stacking in the Vehicle Assembly Building (VAB), Artemis II was fully stacked for launch on Oct. 20, 2025.
Several integrated tests and checkouts occurred in the VAB over the next few weeks, and finally, on Jan. 18, 2026, the full Artemis II stack rolled out to LC-39B for a wet dress rehearsal (WDR) and, ultimately, launch in mid-February.
NASA conducted Artemis II’s first WDR on Feb. 2 and discovered a loose pressurization valve on Orion and a liquid hydrogen (LH2) leak on ML-1. The issues pushed the launch date out of the February window and into the mission’s designated March window. After the required repairs were completed, NASA conducted a second WDR on Feb. 19 and successfully completed the entire simulated launch countdown. The agency then set the launch date for March 6.
The Artemis II crew stand before their SLS and Orion during rollout. From left to right: Wiseman, Glover, Koch, Hansen. (Credit: NASA/John Kraus)
However, on Feb. 21, a helium flow issue in the ICPS would require the entire Artemis II stack to be rolled back to the VAB for repairs. The rollback also delayed the mission’s launch date past the March window and into early April. The issue was fixed, and SLS was rolled back to LC-39B on March 20 after a Flight Readiness Review (FRR) on March 12. The FRR approved seven launch windows, each two hours in length, from April 1 to April 6.
Artemis II vehicles and spacecraft
The full Artemis II stack utilizes components developed by multiple agencies and companies worldwide. The SLS rocket is manufactured by Aerojet Rocketdyne, Boeing, Northrop Grumman, and United Launch Alliance (ULA). The Orion spacecraft is manufactured by Lockheed Martin, while its ESM is manufactured by Airbus Defence and Space for ESA.
SLS is a two-stage super heavy-lift launch vehicle that utilizes LH2, liquid oxygen (LOX), and solid propellants. The first stage, referred to as the core stage, stands 64.6 m tall and 8.4 m in diameter and features four RS-25 engines. At liftoff, these four engines, previously used as main engines on the Space Shuttle stack, produce 7.4 meganewtons of thrust and will burn for 480 seconds during flight.
Boeing manufactures the core stage at NASA’s Michoud Assembly Facility in Louisiana, while Aerojet Rocketdyne provides the RS-25 engines.
At liftoff, the core stage and its RS-25 engines are fired alongside two five-segment solid rocket boosters (SRBs) manufactured by Northrop Grumman. Each booster stands 54 m tall and 3.7 m wide, utilizes ammonium perchlorate composite propellant, and produces 29.2 meganewtons of thrust at liftoff with a 126-second burn time.
Infographic showing the components of the SLS rocket. (Credit: NASA)
Serving as SLS’s second stage for Artemis II is the ULA-manufactured ICPS. The ICPS is a modified version of the Delta Cryogenic Second Stage that flew on ULA’s Delta III and Delta IV rocket families. The 13.7 m tall ICPS is powered by a single RL10C-2 engine from Aerojet Rocketdyne, producing 110.1 kilonewtons of thrust with a maximum burn time of 1,125 seconds.
Sitting between the core stage and the ICPS is the Launch Vehicle Stage Adapter (LVSA) — a cone-shaped interstage that reduces the diameter of the SLS stack from the core stage’s 8.4 m to the ICPS LH2 tank’s five meters. The LVSA is manufactured by Teledyne Brown Engineering.
The Orion spacecraft stack — featuring the ESM, Orion, and launch abort tower — sits atop the ICPS. The ESM provides Orion with power and propulsion capabilities, and is based on ESA’s Automated Transfer Vehicle, which flew to the ISS from 2008 to 2014. Manufactured by Airbus Defence and Space, the ESM stands four meters tall and 5.2 m wide.
The ESM features nine Aerojet Rocketdyne engines; the module’s main engine is a single AJ10 that provides 26.6 kilonewtons of thrust, while eight R-4D engines — each producing 490 N of thrust — serve as secondary engines. The AJ10 main engine was previously used on the Space Shuttle’s Orbital Maneuvering System. Each ESM also features four 7.4 m long solar panel wings that generate 11.2 kilowatts of power for Orion.
The Orion capsule comprises the crew module of the Orion spacecraft stack. Designed and manufactured by Lockheed Martin, Orion stands 3.3 m tall and 5.03 m wide, with a pressurized volume of 19.56 cubic meters and a habitable volume of 8.9 cubic meters.
Orion can carry four-person crews both within and beyond low-Earth orbit for up to 21 days while undocked, or up to six months while docked to another spacecraft. The Orion supporting Artemis II is Orion CM-003 Integrity, named by the Artemis II crew. Integrity is just the second fully assembled Orion spacecraft, and will be the first to support crewed flight.
Infographic showing an expanded Orion spacecraft. (Credit: NASA)
Post-flight inspections of Orion CM-002 following Artemis I revealed unexpected erosion on the capsule’s heat shield from its high-speed reentry into Earth’s atmosphere. The ablative material used on the heat shield is called AVCOAT, and during a 2024 independent review of the Artemis I heat shield erosion, NASA teams found that gases were being trapped within the AVCOAT during reentry, leading to accelerated erosion.
Following the conclusion of the review, NASA announced it would use the same heat shield design for the Orion set to fly on Artemis II, opting to modify the capsule’s reentry trajectory rather than replace the heat shield. This modified trajectory will see Integrity take a steeper descent angle during reentry than Orion CM-002 on Artemis I, limiting the heat shield’s exposure to the heating environment that created the erosion seen on Artemis I. Notably, NASA reported that during Artemis I, temperatures within Orion’s crew compartment remained within acceptable limits.
Lastly, the launch escape tower completes the SLS stack and is directly integrated onto the Orion spacecraft during the initial phases of launch. In the event of an anomaly during ascent that requires a launch abort, the escape motors located near the top of the tower will ignite, safely pulling Orion and its crew away from the failing SLS and allowing Orion to splash down in the Atlantic Ocean. This launch abort system design is often referred to as a “tractor” system.
In total, the SLS stack stands 98 m tall and masses over 2,600,000 kg. Designated a super heavy-lift launch system, SLS is capable of lofting 95,000 kg to low-Earth orbit, and 27,000 kg to TLI.
The completed Orion spacecraft for Artemis II, Integrity, ahead of stacking. (Credit: Lockheed Martin)
Artemis II and SLS will launch from LC-39B at the KSC in Cape Canaveral, Florida. LC-39B is one of three launch pads at KSC, alongside Launch Complex 39A (LC-39A), which is currently operated by SpaceX, and Launch Complex 39C (LC-39C), which is unused.
The launch complex was developed in the early 1960s for the Apollo program, and LC-39B has seen 60 launches to date from the Saturn V, Saturn IB, Space Shuttle, Ares I-X, and SLS rockets. SLS launches from its position atop ML-1, which features fuel and communication umbilical arms and the crew access arm that allows the crew to enter Orion.
Artemis II crew members
Four astronauts will fly on Artemis II, with three from NASA and one from CSA. The international crew represents many firsts in spaceflight, including the first person of color, the first woman, and the first non-American to travel beyond low Earth orbit. The four-person crew will also set the record for the largest number of people in deep space at one time, breaking the record first set by Apollo 8 in December 1968.
Artemis II’s commander is NASA astronaut Reid Wiseman. Born in Baltimore, Maryland, Wiseman attended Rensselaer Polytechnic Institute (RPI) for his undergraduate studies, earning a degree in computer and systems engineering. He later attended Johns Hopkins University, where he graduated with a master’s degree in systems engineering in 2006.
Artemis II’s commander, NASA astronaut Reid Wiseman. (Credit: NASA)
Following his graduation from RPI in 1997, Wiseman joined the United States Navy, where he was designated a Naval Aviator for Fighter Squadron 101 and flew F-14 Tomcat jets. As a member of Fighter Squadron 31, he was deployed to the Middle East during Operations Southern Watch, Enduring Freedom, and Iraqi Freedom. Wiseman was later assigned as a Test Pilot following his graduation from the U.S. Naval Test Pilot School, and he completed additional deployments in South America and the Middle East as a Strike Operations Officer flying the F/A-18F Super Hornet jet.
In June 2009, Wiseman was announced as an astronaut candidate in NASA Astronaut Group 20. At the time of his selection, Wiseman was deployed in the Middle East as a member of Strike Fighter Squadron 103, where he served as a lieutenant commander. Following the completion of his astronaut training, Wiseman was assigned to Expedition 40/41 on the ISS, and he launched to the orbiting laboratory on May 28, 2014, aboard Soyuz TMA-13M. His tour on the Station lasted 165 days. Wiseman then served as Chief of the Astronaut Office from December 2020 until November 2022. Artemis II will serve as Wiseman’s second flight to space.
Artemis II’s pilot is NASA astronaut Victor Glover. Born in Pomona, California, Glover attended California Polytechnic State University (Cal Poly), where he graduated with a degree in general engineering in 1999. Glover later earned a master’s degree in flight test engineering from Air University in 2007, a master’s degree in systems engineering from the Naval Postgraduate School in 2009, and a Master of Military Operational Art and Science degree from Air University in 2010.
Artemis II’s pilot, NASA astronaut Victor Glover. (Credit: NASA)
Like Wiseman, Glover joined the United States Navy following his graduation from Cal Poly and was designated a Naval Aviator in 2001. Flying F/A-18C Hornet jets, he was deployed to the Middle East in support of Operation Iraqi Freedom in 2003. Glover then attended the United States Air Force Test Pilot School, where he graduated as a test pilot in June 2007. In 2011, Glover was deployed to the Western Pacific, serving as a Department Head in support of maritime operations.
Following his deployments in the Western Pacific, Glover was selected for the Legislative Fellowship in 2012 and served as a Legislative Fellow in the U.S. Senate under U.S. Senator John McCain. During his fellowship, Glover earned a Certificate in Legislative Studies from Georgetown University.
In June 2013, NASA announced Glover as a member of NASA Astronaut Group 21. Glover graduated from astronaut training in 2015 and was assigned as the pilot of the SpaceX Crew-1 mission in 2018 — the first crewed operational mission to the ISS under the Commercial Crew Program. Crew-1 launched to the ISS on Nov. 15, 2020, with Glover serving as a Flight Engineer for Expedition 64/65.
During his 167-day mission, Glover conducted four extravehicular activity (EVA) spacewalks and several science experiments. After returning to Earth and before his assignment to Artemis II, Glover served as an HLS crew representative. Artemis II will mark Glover’s second flight to space.
The first of Artemis II’s two mission specialists is NASA astronaut Christina Koch. Born in Grand Rapids, Michigan, Koch was raised in Jacksonville, North Carolina. A graduate of the North Carolina School of Science and Mathematics, Koch earned two bachelor’s degrees in electrical engineering and physics from North Carolina State University (NCSU) in 2001. She returned to NCSU and earned a master’s degree in electrical engineering in 2002. Koch would later receive an Honorary PhD from NCSU.
Artemis II mission specialist, NASA astronaut Christina Koch. (Credit: NASA)
Following her graduation from NCSU, Koch worked as an Electrical Engineer at NASA’s Goddard Space Flight Center’s Laboratory for High Energy Astrophysics, where she developed instruments for several NASA science missions. Koch then served as a Research Associate for the United States Antarctic Program from 2004 to 2007, completing several month-long stays at research stations in the North and South Poles.
She then returned to Maryland, working as an Electrical Engineer at the Johns Hopkins University Applied Physics Laboratory, developing instruments for NASA’s Juno and Van Allen Probes missions from 2007 to 2009. Koch completed subsequent field research tours in Greenland and Antarctica before joining the National Oceanic and Atmospheric Administration as a Field Engineer in Alaska and Station Chief at the American Samoa Observatory.
In June 2013, alongside Victor Glover and seven others, NASA announced Koch’s selection as an astronaut candidate in NASA Astronaut Group 21. Following the completion of her astronaut training in 2015, Koch flew to the ISS aboard Soyuz MS-12 in 2019, serving as a Flight Engineer on Expedition 59/60/61.
In April 2019, Koch’s mission was extended to span three Expeditions, and she returned to Earth in February 2020 after spending 328 days in space — setting the record for the longest single spaceflight by a woman, a record she still holds. Koch also participated in the first all-female spacewalk with NASA astronaut Jessica Meir — who is currently serving onboard the ISS — in October 2019. Artemis II will mark Koch’s second flight into space.
Artemis II’s fourth and final crew member is mission specialist and CSA astronaut Jeremy Hansen. Born in London, Ontario, Hansen graduated from the Royal Military College of Canada with an honors degree in space science in 1999. He returned to the Royal Military College and earned a master’s degree in physics in 2000, with his research focusing on satellite tracking techniques.
Artemis II mission specialist, CSA astronaut Jeremy Hansen. (Credit: NASA)
Hansen joined the Royal Canadian Air Force in 1994 and, following his graduation from the Royal Military College, completed CF-18 Fighter Pilot Training in 2003. From 2004 to 2009, Hansen served as a fighter pilot with the 441 and 409 Tactical Fighter Squadrons flying CF-18s. He also served as the Combat Operations Officer at 4 Wing Operations, where he supported NORAD and Arctic flying operations. Hansen currently holds the rank of Colonel in the Royal Canadian Air Force.
In 2009, CSA announced that Hansen and David Saint-Jacques were selected as astronaut candidates as part of the third Canadian Astronaut Recruitment Campaign. After completing astronaut training in 2011, Hansen participated in ESA’s CAVES program, where he lived underground for six days in Sardinia, Italy, and the NEEMO 19 undersea exploration mission, where he lived underwater for seven days. In 2023, Hansen was assigned to Artemis II, which will serve as his first flight into space.
The Artemis II backup crew consists of NASA astronaut Andre Douglas and CSA astronaut Jenni Gibbons. If any of the three NASA astronauts are unable to launch, Douglas can step in and serve in their positions for the mission. The same applies to Gibbons if Hansen is unable to launch.
Artemis II launch and mission timeline
Artemis II is scheduled to liftoff from LC-39B at 6:24 PM EDT (22:24 UTC) on Wednesday, April 1. The crew entered quarantine in Houston on the evening of Wednesday, March 18, and arrived at the Cape on Friday, March 27, for launch. They will remain in quarantine at the Cape until launch.
The 45th Weather Squadron of Space Launch Delta 45 provides launch weather forecasting for Artemis II. As of Tuesday, March 31, the weather for the April 1 launch window is forecasted to be 80% “go” for launch, with primary weather concerns being the cumulus cloud rule and ground winds. Should the launch suffer a 48-hour delay, the weather for the April 3 launch window is forecasted to be 75% “go,” with the same primary weather concerns as the April 1 window.
NASA utilizes “L-minus” and “T-minus” times to describe the SLS launch countdown. L-minus times indicate the amount of time remaining until launch, while T-minus times reflect pauses in the countdown, called “holds,” that allow team members ample time to correct issues and ensure adequate operations. The provided L-minus time will continuously count down to launch without stopping, but the T-minus time will regularly stop at intended intervals.
Infographic highlighting the trajectory and mission milestones of Artemis II. (Credit: NASA)
The Artemis II launch countdown began on Monday, March 30, at L-49:50:00 hours, when launch teams were called to their respective stations at NASA centers around the country. The launch countdown officially commenced 10 minutes later, and teams at the Cape powered up Integrity, the core stage, and the ICPS from L-45:30:00 hours to L-40:30:00 hours. Teams then spent the next four hours finishing final preparations on the core stage’s four RS-25 main engines. The ICPS was later powered down.
On Tuesday, March 31, from L-33:30:00 hours to L-29:30:00 hours, teams charged Orion’s flight batteries to full power for launch, and then did the same for the core stage’s flight batteries. At the conclusion of core stage battery charging, Artemis II will be about 24 hours away from launch. On Tuesday evening, launch teams will power up the ICPS one final time for launch.
At L-15:30:00 hours, all non-essential personnel will be ordered to leave LC-39B, clearing the area for final launch preparations and SLS fueling operations. At L-13:15:00 hours, the ground launch sequencer (GLS), an automated launch countdown software that handles critical countdown operations, will be activated. A little over two hours later, at L-10:50:00 hours, the launch team will conduct a “go”/”no-go” poll to begin tanking operations.
Moonrise over LC-39B where Artemis II’s SLS awaits its launch. (Credit: Max Evans for NSF)
Assuming launch teams poll “go,” the core stage’s propellant loading systems will be chilled down. At L-09:55:00 hours, core stage LH2 slow fill will begin, while LOX slow fill begins 15 minutes later. The core stage will then undergo LOX fast fill at L-09:30:00 hours, which will continue for the next three hours. LH2 fast fill on the core stage begins at L-09:25:00 hours and continues for the next hour and a half. The core stage LH2 tank is topped off by L-07:55:00 hours and will be continuously replenished until the beginning of terminal count.
Around L-09:00:00 hours, the ICPS is chilled down in preparation for propellant loading, with LH2 fast fill on the ICPS beginning 30 minutes later. The ICPS LH2 tank is topped off by L-07:10:00 hours and, like the core stage, will be replenished until the beginning of terminal count. ICPS LOX fast fill will begin at L-06:30:00 hours. At the same time, Integrity‘s communications systems will be activated, and by L-06:00:00 hours, the core stage’s LOX tank will be fully filled and replenished until terminal count.
At L-06:00:00 hours, the Artemis II crew, now awake and preparing for flight at the Neil Armstrong Operations and Checkout Building (O&C), will be briefed on the latest launch weather forecast. By L-05:10:00 hours, the ICPS LOX tank will be topped off, and replenishment will begin.
The crew will depart the O&C for LC-39B at L-04:40:00 hours and, after meeting the closeout crew in the white room at the end of the crew access arm, board Integrity at L-04:00:00 hours. Over the next two hours after crew ingress, the closeout crew will prepare the Orion hatch for closure and pressurization checks, finally closing the launch abort system hatch at L-01:30:00 hours.
Artemis II crew in their seating positions inside an Orion mockup capsule. (Credit: NASA)
Charlie Blackwell-Thompson, Artemis II launch director, will be briefed at L-01:10:00 hours on the status of the rocket and crew. The closeout crew will depart LC-39B at L-40:00 minutes, at which point the T-minus clock will enter a 30-minute hold at T-10 minutes.
During the hold, teams will transfer to Earth-to-Orion communication loops for launch, and at L-17:00 minutes, the launch director will conduct a “go”/”no-go” poll. If teams give a “go” for launch, the Artemis II crew will close their visors for launch at L-15:00 minutes.
GLS initiates terminal count at L-10 minutes, at which point the T-minus clock begins counting down to launch. At T-08:00 minutes, the crew access arm will retract from Integrity, which switches to internal power at T-06:00 minutes.
Orion’s launch abort system is verified as active and capable at T-05:20 minutes, and the SLS flight termination system is armed at T-04:30 minutes. At T-04:00 minutes, the core stage’s auxiliary power unit (APU) is powered on, and the ICPS and SRBs transfer to internal power at T-02:00 minutes. The core stage switches to internal power at T-01:30 minutes, and at T-01:20 minutes, the ICPS enters terminal countdown mode.
At T-33 seconds, the GLS will initiate the automated launch sequencer, and at T-30 seconds, the core stage’s flight computer will hand control over to the automated launch sequencer. By T-12 seconds, the LC-39B water suppression systems will be activated, and the hydrogen burn-off igniters will be ignited at the base of the core stage. At T-6.36 seconds, the core stage’s RS-25 engines will ignite.
SLS cleares the tower during the launch of Artemis I in November 2022. (Credit: Nathan Barker for NSF)
Finally, at T0, the SRBs will ignite, the ML-1 umbilicals will retract, and Artemis II — humanity’s first mission to the Moon in 52 years — will liftoff from LC-39B.
Immediately after clearing the tower, SLS will undergo a pitch and roll maneuver to place it on the proper flight path. SLS, Integrity, and the Artemis II crew will experience maximum aerodynamic pressure, or the period of ascent where aerodynamic loads are at their greatest, at T+01:10 minutes.
The SRBs will separate at T+02:08 minutes, and the launch abort system tower will be jettisoned at T+03:18 minutes. The core stage will continue to burn for the next several minutes before shutting down at T+08:06 minutes and separating from the ICPS 10 seconds later. Orion’s solar panels deploy at T+20:00 minutes.
At this point, Integrity and its crew will be in a highly elliptical Earth orbit that requires a perigee-raising maneuver; this is done so that, in the event of an emergency, the crew can immediately return to Earth. If all systems and crew are healthy, the ICPS will conduct a perigee raise maneuver at T+49:00 minutes, and then an apogee raise maneuver at T+01:47:57 hours. At the conclusion of this burn, Artemis II will be in a high-Earth orbit, where it will remain until TLI.
An uncrewed Orion flies past the far side of the Moon on the Artemis I mission. (Credit: NASA)
At T+03:24:15 hours, Orion will separate from the ICPS and perform the proximity operations demonstration around it. The ICPS will then burn to reenter Earth’s atmosphere and then deploy cubesats before reentry. The Artemis II crew will then remain in a high-Earth orbit for several hours, performing post-launch and pre-TLI checks and experiments.
Finally, at T+01:01:27 days, Integrity will ignite the AJ10 main engine on the ESM for the TLI burn, setting it on a free-return trajectory around the Moon. Over the next nine days, the crew will conduct a variety of science and engineering experiments, as well as observations of the Moon’s far side during its closest approach at T+05:01:23 days.
The crew will reach their maximum distance from Earth at T+05:01:26 days. Integrity is planned to begin reentry into Earth’s atmosphere at T+09:01:33 days, with a splashdown in the Pacific Ocean off the coast of Southern California coming 13 minutes later.
NSF will publish daily articles for each mission day, highlighting that day’s activities and plans. NSF’s social media accounts, particularly on X, will also provide regular updates on the mission.
(Lead image: Artemis II sits atop LC-39B ahead of its historic mission to the Moon. Credit: Max Evans for NSF)
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