Operational Dynamics of Artemis II: G-Forces, Human Factors, and Crew Performance

The Artemis II mission (April 2–10, 2026) constitutes the first crewed flight beyond low Earth orbit since Apollo 17 in 1972, exposing a four-person crew to the full spectrum of gravitational, physiological, and cognitive challenges inherent to cislunar spaceflight within a compressed 9-day, 1-hour, 32-minute profile. This paper presents a phase-by-phase analysis spanning SLS ascent, translunar injection (TLI), deep-space transit, lunar flyby at a record distance of 252,756 miles from Earth, atmospheric re-entry, and Pacific splashdown. G-forces, communication constraints, and crew performance operate not as isolated variables but as an interdependent triad—determining mission safety margins at every critical phase. Launch and re-entry are identified as the twin peaks of simultaneous physiological stress and information isolation. The paper compares Artemis II's acute episodic stress profile with the chronic deconditioning paradigm of ISS long-duration expeditions, and evaluates risk-mitigation systems—including Orion's semi-supine seat geometry, Solid State Lighting Assembly circadian management, and Optical Navigation autonomous state-vector computation. Sections 1–5 incorporate pre-mission engineering simulations and validated trajectory models; Sections 6–10 additionally integrate post-mission telemetry and NASA's Artemis II assessments released April–May 2026, which confirmed principal parameters within documented tolerances.