Artemis II: Astronaut Experiences and the Physical Challenges of Space Travel

Astronauts from NASA’s Artemis II mission are undergoing extensive Earth-based simulations to relearn basic motor functions such as walking, balance, and coordination after prolonged exposure to microgravity, according to recent reports from Indonesian media outlets covering the mission’s preparations. The training, which includes treadmill work, resistance exercises, and virtual reality simulations, aims to counteract the sensorimotor disruptions caused by spaceflight that can persist for days or even weeks after return to Earth.

Footage shared by Indonesian news platforms such as detikHealth, Kompas.id, and CNBC Indonesia shows crew members practicing locomotion under supervised conditions, often requiring physical support or assistive devices during early stages of reconditioning. These exercises are part of standard post-spaceflight rehabilitation protocols designed to address neurovestibular and proprioceptive impairments resulting from extended periods in weightlessness.

NASA has long documented that astronauts returning from space missions frequently experience difficulties with balance, depth perception, and locomotion — a condition sometimes referred to as “getting their space legs” back. This phenomenon arises because the vestibular system, which governs balance and spatial orientation, adapts to microgravity and must be retrained to interpret gravitational cues correctly upon return to Earth’s 1G environment.

In addition to motor relearning, astronauts face a range of physiological challenges linked to long-duration spaceflight, including fluid shifts that affect vision, muscle atrophy, bone density loss, and changes in cardiovascular function. One well-documented condition is Spaceflight Associated Neuro-Ocular Syndrome (SANS), which can cause structural changes in the eye and impair vision due to increased intracranial pressure in microgravity.

Artemis II, scheduled for launch no earlier than September 2025, will send four astronauts — Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen — on a 10-day journey around the Moon, marking the first crewed mission under NASA’s Artemis program. While the mission does not involve a lunar landing, it will test critical systems for future deep-space exploration, including the Orion spacecraft and the Space Launch System (SLS) rocket.

As part of mission readiness, the crew has undergone extensive training in spacecraft operations, emergency procedures, and extravehicular activity simulations. However, officials emphasize that reconditioning after spaceflight remains a critical phase, requiring individualized rehabilitation plans supervised by flight surgeons, physical therapists, and neurovestibular specialists.

Research conducted by institutions such as the Baylor College of Medicine and NASA’s Johnson Space Center continues to study the long-term effects of spaceflight on the human body, with particular focus on neurological, ocular, and musculoskeletal systems. Findings from past missions, including those aboard the International Space Station, inform current countermeasures designed to protect astronaut health during and after spaceflight.

While the Artemis II crew has not yet flown in space, their pre-mission simulations include analog environments that mimic some aspects of sensorimotor disruption, helping prepare them for the physical challenges of reentry and recovery. Post-mission, they will follow a structured reconditioning program similar to those used after International Space Station expeditions, typically lasting several days to a couple of weeks before full mobility is restored.

As interest in human spaceflight grows, understanding how the body adapts to and recovers from space remains essential for ensuring astronaut safety and mission success. The visible efforts of the Artemis II team to prepare for these physiological transitions underscore the complex interplay between technology and human biology in the pursuit of deep-space exploration.