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The Space Station Freedom (SSF), with a 30-year projected lifetime and a completely closed-loop Environmental Control and Life Support System (ECLSS), is perhaps the ultimate “Tight Building.” Recognizing the potential for the development of “Tight Building Syndrome” (TBS), and initiating actions to minimize possible TBS occurrences on SSF, requires a multidisciplinary approach that begins with appropriate design concerns and ends with detection and control measures on board SSF. This paper will present a brief summary of current experience with TBS on Earth. While many of the circumstances and methodologies garnered from investigating tight buildings on Earth are similar to those that might be encountered aboard SSF, the Station also presents a unique environment and a special set of constraints which will require an adaptation of previous protocols. Air contamination, including volatile organic compounds and microorganisms, will be the focus of the discussion.

For long duration space flights, wastewater from humidity condensate, urine, and used hygiene water will be recycled to provide an adequate supply of potable quality water for the crew. Due to the diverse nature and multiple sources of contaminants entering the recycling system, it is a challenge to maintain the quality of product water such that no adverse health effects occur. NASA Johnson Space Center in cooperation with the Committee on Toxicology of the National Research Council (NRCCOT) has developed a science-based approach, taking into consideration space flight induced factors, to derive Spacecraft Water Exposure Guidelines (SWEG) for 1, 10, 100, 1000 days of consumption. This paper will discuss the ongoing process of setting SWEGs, how candidate chemicals were chosen for risk assessment, and how various toxicological data are collected and interpreted. Our goal is to help environmental engineers understand how the SWEGs they use for hardware design are developed.

Airborne dust, suspended inside a space vehicle or in future celestial habitats, can present a serious threat to crew health if it is not controlled. During some Apollo missions to the moon, lunar dust brought inside the capsule caused eye irritation and breathing difficulty to the crew when they launched from the moon and reacquired “microgravity.” During Shuttle flights reactive and toxic dusts such as lithium hydroxide have created a risk to crew health, and fine particles from combustion events can be especially worrisome. Under nominal spaceflight conditions, airborne dusts and particles tend to be larger than on earth because of the absence of gravity settling. Aboard the ISS, dusts are effectively managed by high efficiency filters, although floating dust in newly-arrived modules can be a nuisance.