The primary specific aim is to evaluate the use of intranasal scopolamine gel and sensory augmentation as an integrated countermeasure to mitigate motion sickness and enhance sensorimotor performance. The proposed intranasal scopolamine gel formulation (Defender Pharmaceuticals, Inc.) offers a safe non-invasive method to self-administer with a rapid onset of action. This study involves a comparison of motion sickness outcome measures when administering intranasal scopolamine gel versus placebo (Aim 1a), and then when administering intranasal scopolamine gel versus placebo with a sensory augmentation belt (Aim 1b).

The primary specific aim is to evaluate the use of intranasal scopolamine gel (DPI-386) and sensory augmentation (SA) as an integrated countermeasure to mitigate motion sickness and enhance sensorimotor performance. The proposed intranasal scopolamine gel formulation (Defender Pharmaceuticals, Inc.) offers a safe non-invasive method to self-administer with a rapid onset of action. The proposed sensory augmentation will utilize vibrotactile feedback of pitch and roll tilt using a portable belt (Engineering Acoustics, Inc.). The investigators will utilize exposure to simulated capsule wave motion on a 6DOF platform to provide an operationally relevant platform to induce motion sickness and impair performance on functional tasks. The investigators hypothesize that the combination of intranasal scopolamine gel and sensory augmentation of Earth vertical will be more effective to mitigate motion sickness and improve task performance than when administered separately. Using a randomized double-blind cross-over design, the investigators will compare motion sickness symptom severity and time to endpoint (symptom level defined as severe malaise) in 30 subjects during exposure to simulated wave motion on a 6DOF platform inside of a crew capsule mockup. The investigators will compare four conditions: (1) intranasal scopolamine gel (0.4 mg) with sensory augmentation, (2) intranasal scopolamine gel (0.4 mg) without sensory augmentation, (3) placebo control with sensory augmentation, and (4) placebo control without sensory augmentation. The wave motion stressor will begin 30 min post drug administration and will not exceed 45 min in duration. Performance on a series of functional tasks (dual-task tracking and eye-hand target acquisition) will be performed pre, during, immediately post, and following 15 min of recovery of each test. The bioavailability of scopolamine for each session will be estimated from plasma concentrations obtained at drug administration and then every 15 min up to 2-hr post-dosage. Subjective side effects and performance on the Psychomotor Vigilance Test (PVT) will also be obtained at 15 min intervals.

A small pilot study including 10 subjects tested once each will be performed to verify the experimental protocol including that the simulated capsule wave motion will provoke motion sickness symptoms. These pilot sessions will not include the medication nor the blood sampling.

Inclusion Criteria:

1. Subjects should be minimally susceptible to provocative motion as evidenced by at least two responses on the Motion Sickness Susceptibility Questionnaire of "Sometimes" or "Frequently."
2. No participants should have neurologic, vestibular or autonomic disorders, or medical conditions that could be worsened by scopolamine (narrow-angle glaucoma or urinary retention
3. Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) negative test, confirmed by Food and Drug Administration (FDA) authorized COVID-19 test < 7 days prior to study drug administration or no COVID 19 symptoms up to 10 days prior to study drug administration.

Exclusion Criteria:

1. Subjects will be excluded if they are taking other drugs that are capable of causing CNS effects such as antihistamines, tricyclic antidepressants, and muscle relaxants or have hypersensitivity to scopolamine or other belladonna alkaloids or to any ingredient or component in the formulation or delivery system.
2. Pregnant women are excluded from participation. Women of child-bearing potential will be offered a pregnancy screening test and excluded with a positive test.

A randomized double-blind (subjects and test operators) cross-over design.