In-flight milestones
The planned trajectory of Artemis II. (Credit: Canadian Space Agency [CSA])
On this page
- Flight day 1: Leaving Earth
- Flight day 1: Proximity operations demonstration
- Flight days 1-10: Systems checkouts
- Flight day 2: Translunar injection
- Flight days 2-5: Heading to the Moon
- Flight day 6: Lunar flyby and observations
- Flight days 7-10: Return to Earth
Artemis II is the first crewed test flight of the Artemis campaign. The mission's objectives are to confirm all of the spacecraft's systems operate as designed with crew aboard in the actual environment of deep space. This is a critical step in establishing a sustainable human presence on the Moon and preparing for future missions to Mars. The crew will also conduct science, both as scientists and research subjects, and make lunar surface observations.
The planned trajectory of Artemis II and the in-flight milestones. (Credit: CSA)
Flight day 1: Leaving Earth
The role of the SLS rocket is to bring Orion into space. It will perform multiple manoeuvres to raise its orbit around Earth and eventually place the crew on a lunar free return trajectory in which Earth's gravity will naturally pull Orion back home after flying by the Moon.
After launch, the SLS will jettison the two side boosters, service module panels, and launch abort system, before the core stage engines shut down and the core stage separates from the upper stage and the spacecraft.
With crew aboard this mission, Orion and the upper stage, called the interim cryogenic propulsion stage (ICPS), will orbit Earth twice to ensure Orion's systems are working as expected while still close to home.
The spacecraft will first reach an initial orbit, flying in the shape of an ellipse, at an altitude of about 185 km by 2,253 km. The orbit will last a little over 90 minutes and will include the first firing of the ICPS to maintain Orion's path. After the first orbit, the ICPS will raise Orion to a high Earth orbit. This manoeuvre will enable the spacecraft to build up enough speed for the eventual push toward the Moon.
The second, larger orbit will take approximately 23.5 hours with Orion flying in an ellipse between about 185 km and 74,000 km above Earth. For perspective, the International Space Station flies a nearly circular Earth orbit about 400 km above our planet.
After the burn to enter high Earth orbit, Orion will separate from the upper stage. The expended stage will have one final use before it is disposed of through Earth's atmosphere – the crew will use it as a target for a proximity operations demonstration to test Orion's manual piloting.
Simulation of Orion approaching the interim cryogenic propulsion stage during testing of Orion's manual piloting. (Credit: NASA)
Flight day 1: Proximity operations demonstration
This series of manoeuvres involves the crew flying Orion, approaching the ICPS, backing away, and manoeuvring for roughly 70 minutes. They will use Orion's onboard cameras and the view from the spacecraft's windows to line up with the ICPS as they approach and back away from it.
This demonstration will provide data and experience that cannot be readily gained on the ground in preparation for critical rendezvous, proximity operations and docking, as well as undocking operations in lunar orbit beginning on Artemis III.
After this demonstration, four international CubeSats, each twice the size of a shoebox, will be ejected from the Orion stage adapter about five and a half hours into the mission.
CSA astronaut Jeremy Hansen and his Artemis II crewmate Christina Koch during Post Insertion and Deorbit Operations training inside the Orion mockup at NASA's Johnson Space Center. The crew practised getting the Orion spacecraft configured once in orbit. (Credit: NASA/Mark Sowa)
Flight days 1-10: Systems checkouts
Following the proximity operations demonstration, the crew will turn control of Orion back to flight controllers at NASA's Johnson Space Center and spend the remainder of the high Earth orbit verifying spacecraft systems in the space environment. They will remove the orange Orion Crew Survival System suit they wear for launch and spend the remainder of the mission in normal clothes. They will only put their spacesuits back on ahead of the re-entry into Earth's atmosphere and the splashdown.
While still close to Earth, the crew will assess the performance of the life support systems necessary to generate breathable air and remove the carbon dioxide and water vapour produced when the astronauts breathe, sleep, talk, or exercise. The checkouts will confirm the full range of life support system capabilities and ensure readiness for the lunar flyby portion of the mission.
The communication and navigation systems will also be verified to confirm they are ready for the trip to the Moon. While still in the elliptical orbit around Earth, Orion will briefly fly beyond the range of GPS satellites and the Tracking and Data Relay Satellites of NASA's Space Network to allow an early checkout of agency's Deep Space Network (DSN) communication and navigation capabilities. When Orion travels out to and around the Moon, Mission Control will depend on the DSN to communicate with the astronauts, send imagery to Earth, and command the spacecraft.
On the remainder of the trip, astronauts will continue to evaluate the spacecraft's systems, including demonstrating Earth departure and return operations, practising emergency procedures, and testing the radiation shelter.
Orion reached its maximum distance from Earth on flight day 13 of the Artemis I mission. (Credit: NASA)
Flight day 2: Translunar injection
After the main checkout procedures are completed, and if all the critical systems are in order, the decision will be made to proceed with the journey to the Moon.Footnote 1 By then, Orion will have remained in high Earth orbit for about 25 hours before executing the translunar injection (TLI) engine burn that will set it on course to the Moon. The TLI burn will last about 5 minutes 45 seconds.
Flight days 2-5: Heading to the Moon
The service module, provided by the European Space Agency, will provide that last push needed to send Orion and its crew on a trip of about four days around the backside of the Moon where they will ultimately create a figure eight extending over 370,000 km from Earth and do a flyby before returning home.
The crew will have opportunities to connect with people on Earth during space-to-Earth video connections while they are heading to the Moon. Jeremy is expected to connect with Canadians during special events held at CSA headquarters on flight days 3, 4 and 5.
On flight day 5, Orion will enter the lunar sphere of influence, the point at which the Moon is pulling on the spacecraft harder than Earth is.
Orion's optical navigation camera took this black-and-white image of the craters of the Moon during Artemis I. (Credit: NASA)
Flight day 6: Lunar flyby and observations
The next day, Orion is expected to fly 6,400 km to 9,700 km from the Moon's surface. From that vantage point, the Moon will look like a basketball held at arm's length. The crew will be able to see Earth and the Moon from Orion's windows, with the Moon close in the foreground and Earth over 400,000 km in the background. The crew could also be the first humans to see, with the naked eye, parts of the Moon's far side never observed before.
For a little over five hours, the crew will take turn observing and photographing geological features on the Moon like impact craters, ancient lava flows, and possibly regions like the Orientale Basin. With real-time data analysis, guidance provided by a team of scientists and the knowledge acquired through their geology training in Labrador, Iceland and in class to describe surface textures, shapes, and colours, providing valuable data for future exploration of the Moon.
On flight day 7, Orion will leave the lunar sphere of influence en route back to Earth.
The flyby in numbers
Estimated maximum distance from Earth: about 370,000 km
Estimated distance beyond the far side of the Moon: nearly 7,400 km
Note: These distances will be confirmed after the launch and TLI burn.
Flight days 7-10: Return to Earth
On flight day 7, Orion will start making its four-day journey back to Earth.
Instead of requiring propulsion on the return, the fuel-efficient "free return trajectory" harnesses the Earth-Moon gravity field, ensuring that after its trip around the far side of the Moon, Orion will be pulled back naturally by Earth's gravity.
Once the Crew Module separates from the Service Module, it will re-enter Earth's atmosphere at 32 times the speed of sound. The heat shield and the friction with the atmosphere will help bleed out a lot of the speed. As the spacecraft gets down into the thicker parts of the atmosphere, drogue chutes will come out before the three main parachutes to slow it down for a safe landing.
Less than 15 minutes after re-entry, the Crew Module will splash down in the Pacific off the coast of San Diego, California. After travelling more than 2 million km in nearly 10 days, the Orion capsule and its crew will be recovered by NASA and the U.S. Navy, ending this historic mission around the Moon.
Prepared with material from NASA.
When Orion splashes down in the Pacific Ocean after its journey around the Moon, an intricate operation to recover the crew and the capsule safely will get into gear. The crew and the teams involved in the recovery practise the operation both in a pool and in the ocean several times before the mission. CSA astronauts Jeremy Hansen and Jenni Gibbons give us an insider's look at one of these training sessions at NASA's Neutral Buoyancy Laboratory. (Credits: CSA, NASA, Fulwell 73 UK Limited)