Glossary & Acronyms
Glossary stub: 25 of a planned ≈150 terms. Definitions pending editorial review. Metadata CC0.
- ALARA — As low as reasonably achievable
- Radiation-protection principle: keep exposure as low as reasonably achievable even when below limits; required for NASA crews ([V1 4029]). space-radiation
- ARED — Advanced Resistive Exercise Device
- ISS resistance-exercise machine providing loads up to 600 lbf; associated with better bone and muscle protection than earlier devices. bone-loss
- CMO — Crew Medical Officer
- Crewmember (usually not a physician) trained to deliver medical care in flight under ground flight-surgeon guidance; NASA requires at least two per vehicle.
- DCS — Decompression sickness
- Illness from dissolved inert gas (nitrogen) forming bubbles when ambient pressure falls — in divers, aviators, and astronauts moving from cabin pressure to a low-pressure spacesuit.
- DMCF — Definitive medical care facility
- Pre-arranged, trauma-capable hospital that receives crew after launch or landing emergencies.
- DXA — Dual-energy X-ray absorptiometry
- Low-dose X-ray scan measuring bone mineral density (T- and Z-scores); NASA uses it for selection, triennial surveillance and post-flight follow-up. bone-loss
- EVA — Extravehicular activity
- Activity performed by an astronaut outside a spacecraft, commonly called a spacewalk.
- GCR — Galactic cosmic rays
- High-energy charged particles originating outside the solar system, including heavy (HZE) ions. space-radiation
- HSP — Health Stabilization Program
- Preflight measures (e.g., limiting contacts, screening) that reduce the chance crew carry infectious disease into flight.
- IIH — Idiopathic intracranial hypertension
- Raised intracranial pressure without a mass lesion, causing papilledema and headache; shares some findings with SANS but is a different condition. sans
- LBNP — Lower body negative pressure
- Device applying suction to the lower body to pull fluid toward the legs; studied as a countermeasure for headward fluid shift and SANS. sans
- LEO — Low Earth orbit
- Earth orbit at altitudes up to about 2,000 km; the ISS orbits in LEO.
- OCHMO — Office of the Chief Health and Medical Officer
- NASA office that owns NASA-STD-3001 and publishes its technical briefs.
- OCT — Optical coherence tomography
- Non-invasive retinal and optic nerve imaging; used in flight and on the ground to detect optic disc edema and choroidal folds in SANS. sans
- OI — Orthostatic intolerance
- Inability to maintain blood pressure and cerebral perfusion when upright, causing lightheadedness or fainting; common after returning from spaceflight. orthostatic-intolerance
- PMC — Private medical conference
- Confidential crew-to-flight-surgeon medical consultation during a mission.
- POCUS — Point-of-care ultrasound
- Ultrasound performed and interpreted at the bedside by the treating clinician; on the ISS, often acquired by non-physician crew under remote guidance.
- Prebreathe — Oxygen prebreathe
- Breathing 100% oxygen before decompression to wash nitrogen out of tissues and reduce the risk of decompression sickness before a spacewalk.
- REID — Risk of exposure-induced death
- Estimated added lifetime probability of dying from cancer caused by a radiation exposure; NASA's career limit is set to keep mean REID under 3%. space-radiation
- RIDGE — Radiation, Isolation, Distance, Gravity, Environment
- NASA's five-hazard framework for human spaceflight.
- SANS — Spaceflight-associated neuro-ocular syndrome
- Ophthalmic and neuro-ophthalmic findings associated with long-duration spaceflight; formerly called VIIP. sans
- SFP — Spaceflight participant
- A non-professional crew member, e.g. on a commercial flight.
- SMS — Space motion sickness
- Motion-sickness symptoms during early adaptation to weightlessness. space-motion-sickness
- SPE — Solar particle event
- An episode of elevated energetic particle (mainly proton) flux from the Sun, often associated with flares and coronal mass ejections. space-radiation
- VGE — Venous gas emboli
- Gas bubbles in venous blood after decompression, detectable by Doppler or ultrasound; often asymptomatic and used to gauge decompression stress.