Artemis II: Trans-Lunar Insertion Maneuver Completed, Orion Spacecraft Headed to the Moon
For about an hour now, the Trans-Lunar Injection (TLI) maneuver has been completed, bringing the Orion Integrity capsule with the crew of Artemis II on its way to the Moon for a close flyby and return to Earth. Overall, the mission will last about 10 days from the moment of launch, which took place yesterday.
As expected, the European Service Module (ESM) ignited its main engine to set the spacecraft on a trajectory with a perigee of over 400 thousand km towards the Moon. This is a significant moment as it transitions from an elliptical Earth orbit to the TLI, a feat not accomplished since the end of the Apollo program (in the early '70s), considering crewed missions.
Next stop: lunar flyby.
The Orion spacecraft recently ignited its main engine on the service module for about six minutes to provide around 6,000 pounds of thrust. This maneuver sets the Artemis II astronauts on the path to the Moon.
After acclimating to the spacecraft in the space environment and resolving some minor issues that arose in the hours following the launch, the Artemis II crew is now traveling towards our natural satellite. Late last night, there was a "GO" for executing the maneuver, as the systems responded correctly.
Artemis II is on its way to the Moon.
As explained by Tobias Langener (head of the ESM propulsion system at ESA), "this is an exciting moment for the teams as they decide to send the astronauts and Orion to the Moon, utilizing the main engine of the ESM. It’s a fairly long maneuver, but we are confident – we have already seen great performance from the vehicle in the first mission."
At the top, the two OSM engines, centrally the three RS-25 engines.
Luca Fossati (flight system engineer for ESM at ESA) added that "since no further large engine ignitions will be necessary, only small course corrections here and there, it means the mission team can afford to use much of the ESM propellant for the ignition dedicated to TLI."
The main engine of the ESM is a refurbished Orbital Maneuvering System (OSM) engine that has already flown six times on the Space Shuttle Atlantis. Other engines are present for maneuvers, but this is the only one available on the capsule capable of providing the necessary acceleration to send a crewed spacecraft from Earth orbit to the Moon.
The main engine of Orion
Before the actual ignition (which occurred at 1:49 AM today, Italian time, lasting 5'50"), the Orion propulsion system is prepared. This means that the propellant tanks are brought to the correct pressure, the thrust vector control system is rechecked, and the spacecraft is oriented in the right direction. The capsule can utilize eight auxiliary engines for larger adjustments and as a backup for the main engine, as well as 24 attitude control thrusters for smaller changes.
Victor Glover (mission pilot) wrote at the end of 2025 in a post that, "Perspective: when we give the green light to the trans-lunar insertion maneuver (TLI) and the engines of the Orion Integrity service module push us towards the Moon, our actual destination will be Earth. The final destination of every human spaceflight."