Aerosol Sprays: The propellant in aerosol cans can create tiny, flammable droplets in microgravity, which pose a fire hazard in the confined spaces of a spacecraft.
Alcohol: Alcohol consumption and storage are prohibited in space as it can impair cognitive and motor functions, which are critical in the space environment. Additionally, alcohol evaporates easily and could interfere with the spacecraft’s systems.
Loose Powder: Items like talcum powder or makeup in loose powder form are restricted because, in zero gravity, particles can float and clog ventilation systems, enter astronauts' eyes, or contaminate equipment.
Carbonated Drinks: Bubbles behave differently in microgravity, remaining suspended in liquid rather than rising. This makes carbonated drinks uncomfortable and difficult to drink, as the carbonation doesn’t settle well in the stomach.
Bread and Crumbly Foods: Regular bread or foods that create crumbs aren’t allowed, as crumbs can float around, potentially getting into equipment or astronauts’ eyes, creating both safety and hygiene concerns.
Flammable Fabrics: Items made from flammable materials, like untreated cotton or polyester, aren’t allowed since fire risk is heightened in oxygen-rich environments, and fires are challenging to control in a spacecraft.
Unshielded Sharp Objects: Any sharp object can puncture or damage sensitive equipment or pose a hazard to astronauts in microgravity, so such objects must be carefully shielded or avoided entirely.
Soil and Plants with Soil: Soil can contain bacteria and mold that could contaminate the sterile spacecraft environment. Additionally, floating soil particles could affect air quality and equipment, so plant growth uses hydroponics or carefully controlled growth mediums instead.