Developing an Earth-Fixed Visual Reference to Aid Stability, Readaptation, and Egress After A Water Landing

Water landings present the worst possible sensory conditions for crews trying to
orient and stabilize themselves immediately after long-duration spaceflight. Of the
three sensory feedback systems involved in maintaining stability (i.e.,
proprioceptive, vestibular, and visual), none will provide reliable orientation
information under the current water landing scenarios. The proprioceptive and
vestibular systems are affected during spaceflight by disuse and adaptation to
microgravity. Vision may not suffer the same degradation, but the visual
environment within the enclosed space of a capsule, or interior room of a recovery
ship, induces instability during wave motion. In
addition to an increased fall risk, sensory readaptation is delayed until inputs from the three
sensory systems can be synchronized with one
another and aligned with Earth’s gravity. An
Earth-fixed visual reference (EFVR) can be
provided to increase crewmember stability and
allow for earlier readaptation initiation.