Neurobehavioral Changes Following Spaceflight Stressors

Inclusion Criteria: * Age between 21-60 years. * Free of psychological, psychiatric or physical conditions that preclude participation. * BMI between 18.5 and 35. * Self-reported regular sleep schedule; able to maintain their sleep schedule during the course of the study. * Self-reported sleep duration of 6-8.5 h per night (verified by daily logs). * Ability to read/write English. * Able to stand unassisted for up to 10 minutes at a time and able to lift arms above head. Exclusion Criteria: * Alcohol or drug abuse in the past year based upon history and urine toxicology screen. * Potential alcohol abuse or heavy drinking in the past year, based on self-report (AUDIT-C Q2 score above 1 or Q3 score above 2). * Alcohol-naive based on self-report (AUDIT-C Q1 score of 0). * Allergies, conditions or circumstances that preclude alcohol consumption, including use of medication or supplements (prescription or over the counter) that could interfere with study participation or make it hazardous for a subject to partake (e.g., anticholinergics; antipsychotics; lithium; psychotropic drugs not otherwise specified), or for which alcohol consumption should be limited or avoided (e.g. items identified on NIAAA's 'Harmful Interactions' list). * Cultural or personal beliefs that preclude alcohol consumption. * Body Mass Index ≤18.5 or ≥ 35. * Current smoker/tobacco user or using nicotine replacement therapy. Those that have been nicotine-free for ≥ 30 days may be included. * Excessive caffeine consumption (\> 650mg/day combining all caffeinated drinks regularly consumed during the day). * Acute, chronic, or debilitating medical conditions, major Axis I psychiatric illness based on history, physical exam, blood and urine chemistries; or self-reported history of neurological, psychiatric, or other medical condition that precludes participation, such as nervous system disorders, dementia, chronic migraines, or epilepsy; panic, bipolar or schizoaffective disorder; sleep disorders including insomnia, narcolepsy and obstructive sleep apnea; liver, kidney or heart disease, hypertension; infectious diseases; diabetes; or any other conditions for which medical monitoring is advised and which may require medications and/or lifestyles that preclude alcohol consumption and/or sleep disruption. * Current depression as determined on the Beck Depression Inventory (Beck, 1996), by either a total score of 19 or higher or a response greater than 0 on Q9 (suicidality). * Cardiovascular, gastrointestinal, or musculoskeletal problems, or other major conditions such as organ failure, cancer or patients requiring oxygen. * Prior history or diagnosis of any sleep disorder including Obstructive Sleep Apnea (AHI ≥15 events/hour) - from ambulatory or in lab polysomnography; Restless legs syndrome or periodic limb movement disorder; Insomnia; Parasomnia; High Risk of OSA based on STOP-BANG Questionnaire ("yes" on at least 4 of 8 questions); High Risk of Restless Legs Syndrome (RLS) based on Cambridge-Hopkins Screening questionnaire; High Risk of Insomnia based on Insomnia Severity Index (score of 22 or higher). * Current use or use within the past month of a prescription or over-the-counter sleep medication or stimulant (based on self-report or review with a study clinician). * History of potential MRI contraindications, including: tinnitus; sensorineural hearing loss \> 30 dB; pace maker or internal defibrillator; metallic implants (e.g. orthopedic plates after bone fractures, joint replacements, surgical staples or clips, artificial heart valves, stents, cava filters); metallic splinters (e.g. after an accident or due to war injury); non-removable dental brace; Tattoo (some tattoo inks contain metallic particles); permanent make-up; non-MRI compatible intrauterine contraceptive device; cochlear implant (implanted hearing device); medication pump; acupuncture needle; other foreign bodies/objects which are non-removable; pregnancy (or its possibility); previous brain and/or heart surgery. * History of severe motion sickness, based on self-report or driving simulator response. * Pregnant or currently breast feeding. People that menstruate will have a pregnancy test performed via urine sample during screening, as those that are currently pregnant are unable to participate in the study. * Individuals who self-report severe contact dermatitis or allergy to bandages, silicone, nickel or silver. * Currently working night, swing, split or rotating shift. * Planned travel across more than one time zone within 7 days of the scheduled study start date. * Habitual daytime napping.