Washington, DC (May 29)Work on a quarantine facility must begin soon if it is to be ready in time for spacecraft returning to Earth with Martian rocks and soil in tow, says a new report from the National Academies' National Research Council. Although the probability is extremely low that these samples will contain hazardous organisms, prudence dictates that all material must be rigorously quarantined at first.
With current projections indicating that the first sampling mission to Mars could launch in 2011, Martian samples could reach Earth as early as 2014. A facility that isolates the samples from terrestrial organisms and chemicalswhile safeguarding the Earth's environment from possible contaminationwill probably take 7 years or more to design, build, and test.
Building this type of quarantine facility is a project of enormous complexity, said John Wood, chair of the committee that wrote the report and staff scientist at the HarvardSmithsonian Center for Astrophysics, Cambridge, MA. We strongly recommend that this process get under way as soon as possible.
One major problem in constructing such a facility is the unprecedented need for both biological containment and clean-room conditions. Biological containment is designed to protect the Earth's environment from possible contamination by the samples. Clean-room conditions are needed to prevent terrestrial organisms, dust, or other foreign matter from getting into the samples and changing their properties. Part of the problem is that contradictory measures are traditionally employed in these two types of facilities. Biological containment facilities enclose samples at lower-than-ambient air pressures so any leakage moves air into the sample chamber and away from the external environment. Clean-room cabinets, on the other hand, are held at greater-than-ambient gas pressures so leakage is outward, protecting the enclosed samples from external contamination.
Because a facility combining these features has never been built, extensive experimentation and testing will be needed to design a system of two-way protection. This must be accomplished before design work on the actual Mars quarantine facility begins. Experimentation also is needed to identify effective sterilization techniques that have a minimal impact on the physical and chemical properties of the samples. The report recommends that a continuing committee of biological and geochemical experts be assembled to oversee all aspects of planning, construction, and operation of the quarantine facility.
To maximize resources and expedite the process of meeting environmental requirements, the quarantine facility should be affiliated withand located adjacent toan existing containment facility such as those operated by the Centers for Disease Control and Prevention in Atlanta, the U.S. Army Medical Research Institute for Infectious Diseases in Fort Detrick, MD, or the facility projected by the medical branch of the University of Texas at Galveston. However, NASA should operate and be responsible for the quarantine facility, the report recommends.
Because operations in a maximum-security containment facility are highly constrained, the report recommends that only the most basic preliminary examination necessary to document the samples and test them for biohazards should be carried out there. Once the samples are cleared for release, a broader range of examinations should be carried out elsewhere. Plans should be in place to promptly sterilize a portion of the samples after they are received so they can be safely transferred out of the facility for study in specialized university laboratories.
The committee proposed specific guidelines for release of samples from the facility. If found to contain no organic matter or other evidence of life, they could be released without sterilization. If the samples contain possible evidence of life, which is the most likely case, portions that have been sterilized by heat or g-radiation could be certified for release and study elsewhere. If the samples are found to contain unmistakable evidence of life, they should not be released at all until an expert panel of biologists is convened to rethink the situation; the establishment of a research facility dedicated to their study, far more extensive than the quarantine facility, will probably be justified.
The study was sponsored by NASA. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provides independent advice on science and technology issues under a congressional charter. A committee roster follows.
The Quarantine and Certification of Martian Samples will be available on the World Wide Web at www.nap.edu/catalog/10138.html. The Academies' Web site also will feature supplemental information and an extended Web treatment at http://national-academies.org/.