Artemis II was originally designated Exploration Mission-2 (EM-2) and was initially intended to support the now-canceled Asteroid Redirect Mission. Its objectives were revised following the establishment of the Artemis program.
Mission planning and launcher selection (2017–2021)
In 2017, Exploration Mission-2 was a projected single-launch mission of a Space Launch System (SLS) Block 1B rocket with an Exploration Upper Stage, lunar Block 1 Orion spacecraft, and a payload insertion of 50.7 tonnes (55.9 short tons; 112,000lb). The plan was to rendezvous with an asteroid previously placed in lunar orbit by the robotic Asteroid Redirect Mission and have astronauts perform spacewalks and gather samples.[3][4] After the cancellation in April 2017[5] of the Asteroid Redirect Mission, an 8-day mission was proposed with a crew of four astronauts, sent on a free-return trajectory around the Moon.[6] Another proposal suggested in 2017 was to take four astronauts aboard Orion on an 8-to-21–day trip around the Moon to deliver the first element of the Deep Space Gateway.[7] In March 2018, it was decided to launch the first Gateway module on a commercial launch vehicle[8] because of delays in building the Mobile Launcher needed to hold the more powerful Exploration Upper Stage.[9] The launcher was selected to be the SpaceX Falcon Heavy.[10]
Hardware development, testing and integration (2021–present)
Artist's rendition of the Orion spacecraft in lunar orbitSLS core stage for Artemis II lifted into High Bay 2 of the Vehicle Assembly Building shortly after stacking operations began in December2024
On February 11, 2023, NASA rotated the Artemis II core stage's engine section to a horizontal position, marking the final major milestone before integration with the rest of the vehicle. On March 20, the engine section was mated with the core stage in Building 103 at the Michoud Assembly Facility in New Orleans. NASA initially expected to deliver the completed core stage to Kennedy Space Center (KSC) in summer 2023,[11] but by May, the timeline had shifted to late fall 2023.[12][13]
RS-25 engines with serial numbers E2047, E2059, E2062, and E2063 were installed on the core stage in New Orleans by September 25, 2023.[14][15] However, after a leak was discovered in its oxygen valve hydraulics, engine E2063 was replaced with E2061 in April 2025.[16]
In June 2024, NASA announced that the fully outfitted core stage was scheduled for delivery to KSC in July, which was successfully carried out from the 16th to the 25th.[17][18][19] The adapters required for integration of the full launch vehicle also reached substantial completion in June 2024 and arrived at KSC in September 2024.[20][21]
NASA had originally targeted September 2024 to begin rocket stacking operations. However, the schedule was delayed by more than two months due to investigations into issues with Orion's life support system and unexpected damage to Orion's heat shield observed after the Artemis I reentry.[24] Rocket stacking finally began on November 20, 2024.[25]
Launch date
During preliminary reviews in 2011, the launch date was placed somewhere between 2019 and 2021, but afterwards the launch date was delayed to 2023.[26][27] In January 2024, the mission was expected to launch in September 2025.[28] However, in October 2024, the NASA Office of Inspector General determined that the Exploration Ground Systems team had already used up their time reserved for resolving any unforeseen issues, leading the office to determine that the September 2025 launch date would likely be delayed.[24] In December 2024, outgoing Administrator Nelson announced that the launch was delayed due to the months of engineering investigations into issues with the life support system and heat shield, but they were targeting a launch in April 2026.[29][30]
In March 2025, AmericaSpace reported that the mission might be accelerated, with the launch date potentially moved up by two months to February 2026. NASA responded in a statement, saying it could not confirm the revised date but noted, "We’re looking for ways to enable an earlier launch if possible, potentially launching as soon as February 2026. A February target allows the agency to capitalize on efficiencies in the flow of operations to integrate the SLS rocket, Orion spacecraft, and supporting ground systems while maintaining crew safety as the top priority."[31] By August 2025, more mainstream outlets such as NASASpaceflight, journalist Eric Berger and US Senator and former astronaut Mark Kelly also reported that the mission had been moved up to February 2026.[32][33] However, as of September 2025, NASA's official mission webpage still lists the launch date as April 2026.[34]
Launch opportunities
For the launch of lunar missions there are both monthly windows of a few days duration each lunar month, and daily windows lasting a few hours on days within the monthly window.[35] The revised Artemis II plan, which calls for Orion to conduct a shorter skip reentry, further constrains the days within a monthly window during which a launch can be conducted.[36]
Crew
The backup (standing left) and prime crew of Artemis II after a news conference in December 2024
Glover will become the first person of color, Koch the first woman, and Hansen the first non-American to travel to the Moon. Hansen and Gibbons, both from Canada, were selected by the Canadian Space Agency as part of a 2020 treaty between the United States and Canada that facilitated their participation in the Artemis program.[37][40]
Mission
Diagram showing the planned objectives of the Artemis II mission
The Artemis II mission plan is to send four astronauts in the first crewed Orion spacecraft into a lunar flyby using the Block 1 variant of the Space Launch System. The mission profile is a multi-trans-lunar injection (MTLI), or multiple departure burns, and includes a free-return trajectory from the Moon. The Orion spacecraft will be sent to a high Earth orbit with a period of roughly 24 hours. During this time the crew will perform various checkouts of the spacecraft's life support systems as well as an in-space rendezvous and proximity operations demonstration using the spent Interim Cryogenic Propulsion Stage (ICPS) as a target. When Orion reaches perigee once again, it will fire its main engine to complete the TLI maneuver, which will send it onto a lunar free-return trajectory, before returning to Earth.[2][41]
Optical communications
Optical Communications System modules on the Orion spacecraft
Artemis II will test and demonstrate optical communications to and from Earth using the Orion Artemis II Optical Communications System (O2O).[42] The O2O hardware will be integrated into the Orion spacecraft and includes an optical module (a 4-inch [100mm] telescope and two gimbals), modem and control electronics.[42] O2O will communicate with ground stations in California and New Mexico.[42] The test device will send data to Earth with a downlink rate of up to 260 megabits per second.[43]
Mission overview
The crew of Artemis II training inside an Orion mock-up in January2025
Artemis II's trajectory can be divided into several key phases, over an approximately ten day trip:[44][34]
Launch
Vehicle: Space Launch System (SLS) Block 1
Launch Site: Kennedy Space Center, Launch Complex 39B
Duration: Approximately 8 minutes to reach initial orbit
Trajectory: The SLS will launch Orion into a low Earth orbit (LEO) for a very short period of time, then fire again to place Orion in a highly-eccentric orbit with a period of about 24 hours.
Earth orbit and systems checkout
Orbit: Highly-eccentric orbit with an apogee above that of typical communications satellites
Duration: About 24 hours
Activities: The crew will perform checks on the Orion spacecraft's systems, ensuring all are functioning correctly before proceeding with the mission. They will also demonstrate proximity operations with the upper stage of their launch vehicle.
Translunar injection
Maneuver: After the systems checkout, the Orion spacecraft will perform a TLI burn using its Service Module, propelling it out of Earth orbit towards the Moon
Trajectory: A precise burn to place Orion on a trajectory that will take it around the Moon.
Lunar flyby
Altitude: Closest approach approximately 7,400 kilometers (4,600mi) from the lunar surface
Duration: Several days to travel to the Moon, fly around it, and begin the return trip
Activities: The crew will continue to monitor and test Orion's systems and gather data on deep space travel effects.
Return trajectory
Maneuver: After the lunar flyby, Orion will use the Moon's gravity to assist in its return to Earth, a maneuver known as a free-return trajectory
Trajectory: A path that will naturally bring Orion back to Earth without the need for additional propulsion if systems fail.
Re-entry and splashdown
Re-entry Phase: Orion will re-enter Earth's atmosphere
Splashdown: In the Pacific Ocean, recovery teams will retrieve the spacecraft and crew
Duration: The entire mission is expected to last about 10 days.
CubeSat secondary payloads
NASA's CubeSat Launch Initiative (CSLI) originally sought proposals in 2019 from U.S. institutions and companies to fly CubeSat missions as secondary payloads aboard the SLS on the Artemis II mission.[45][46] NASA planned to accept 6-unit (12kg, 26lb) and 12-unit (20kg, 44lb) CubeSats,[47] which would be mounted on the inside of the stage adapter ring between the SLS upper stage and the Orion spacecraft, deploying after Orion separated into high Earth orbit.[47] Although selections were initially expected by February 2020,[45] all secondary payloads were removed from the mission in October 2021.[48]
In September 2024, NASA announced that it would fly five CubeSats from international partners aboard the Artemis II mission. The payloads, selected from nations that are signatories of the Artemis Accords, are intended to advance global scientific and technological research while broadening international access to deep space. The first CubeSat selected was Germany's TACHELES, which will examine the impact of space conditions on electrical components used in lunar vehicles.[49] In May 2025, NASA announced that it had selected the ATENEA satellite from Argentina's National Space Activities Commission to join the mission, with goals to study radiation shielding, map the surrounding radiation environment, gather GPS data for mission planning, and test a long-distance communication system. CubeSats from the Korea Aerospace Research Institute and the Saudi Space Agency are also slated to fly, with all five payloads bound for High Earth orbit.[50]
Similar missions
In December 1968, the Apollo 8 mission, crewed by astronauts Frank Borman, Jim Lovell, and William Anders, flew their command and service module beyond low Earth orbit and completed ten orbits of the Moon. Similar to the planned Artemis II mission in that it was crewed and did not land, it differed by being placed into orbit.[51]Apollo 13 (1970) was the only Apollo mission, and only crewed spaceflight to date, that flew past the Moon by a free-return trajectory.
↑ "NASA FY 2019 Budget Overview"(PDF). NASA. p.14. Archived(PDF) from the original on December 4, 2019. Retrieved November 12, 2021. Supports launch of the Power and Propulsion Element on a commercial launch vehicle as the first component of the LOP – Gateway This article incorporates text from this source, which is in the public domain.
↑ Berger, Eric (April 13, 2018). "NASA may fly crew into deep space sooner, but there's a price". Ars Technica. Archived from the original on October 26, 2019. Retrieved April 6, 2023. Without the Exploration Upper Stage, NASA will not be able to fly, in a single flight, crew members and pieces of a deep space gateway it hopes to build near the Moon in the 2020s
1 2 Hill, Denise (August 6, 2019). "NASA's CubeSat Launch Initiative Opens Call for Payloads on Artemis 2 Mission". NASA. Archived from the original on August 6, 2019. Retrieved August 6, 2019. NASA is seeking proposals from U.S. small satellite developers to fly their CubeSat missions as secondary payloads aboard the SLS on the Artemis 2 mission under the agency's CubeSat Launch Initiative (CSLI) This article incorporates text from this source, which is in the public domain.
↑ Klotz, Irene (August 5, 2019). "NASA Scouting Cubesats For Artemis-2 Mission". Aviation Week & Space Technology. Archived from the original on August 6, 2019. Retrieved August 6, 2019. NASA on August 5 released a solicitation for cubesats to ride along with the first crewed flight of the Space Launch System rocket and Orion capsule, with the caveat that selected projects fill strategic knowledge gaps for future lunar and Mars exploration
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