Preventing Back Contamination

There are three fundamental approaches toward handling extraterrestrial samples to avoid back contamination. First, scientists could sterilize a sample while it is en route to Earth from its native world. Second, they could place it in quarantine in a remotely located, maximum-confinement facility on Earth while scientists examine it closely. Finally, they could also perform a preliminary hazard analysis (called the extraterrestrial protocol tests) on the alien sample in an orbiting quarantine facility before they allow the sample to enter the terrestrial biosphere. To be adequate, a quarantine facility must be capable of (1) containing all alien organisms present in a sample of extraterrestrial material, (2) detecting these alien organisms during protocol testing, and (3) controlling these organisms after detection until scientists could dispose of them in a safe manner.

One way to bring back an extraterrestrial sample that is free of potentially harmful alien microorganisms is to sterilize the material during its flight to Earth. However, the sterilization treatment used must be intense enough to guarantee that no microbial life-forms as exobiologists currently know or anticipate them could survive. An important concern here is also the impact that the sterilization treatment might have on the scientific value of the alien world sample. For example, use of chemical sterilants would most likely result in contamination of the sample, thereby preventing the measurement of certain soil properties. Heat could trigger violent chemical reactions within the soil sample, resulting in significant changes and the loss of important exogeological data. Finally, sterilization would also greatly reduce the biochemical information content (if any) within the sample. It is quite questionable as to whether any useful exobiology data can be obtained by analyzing a heat-sterilized alien material sample. To put it simply, in their search for extraterrestrial life-forms, exobiologists want "virgin alien samples."

If scientists decide not to sterilize the alien samples en route to Earth, they then have only two general ways to avoid potential back contamination problems. First, they can deliver to and secure the unsterilized sample of alien material in a maximum quarantine facility on Earth. The scientists would then conduct detailed scientific investigations on the sample in this isolated terrestrial laboratory. The second choice is for the scientists to intercept and inspect the sample at an orbiting quarantine facility (OQF) before allowing the material to enter Earth's biosphere.

The technology and procedures for hazardous-material containment have been used on Earth in the development of highly toxic chemical- and biological-warfare agents and in conducting research involving highly infectious diseases. A critical question for any quarantine system is whether the containment measures are adequate to hold known or suspected pathogens while experimentation is in progress. Since the characteristics of potential alien organisms are not presently known, scientists must assume that the hazard such (hypothetical) microorganisms could represent is at least equal to that of terrestrial Class IV pathogens. (A terrestrial Class IV pathogen is an organism that is capable of being spread very rapidly among humans: No vaccine exists to check its spread; no cure has been developed for it; and the organism produces high mortality rates in infected persons.)

Judging from the large uncertainties associated with potential extraterrestrial life-forms, it is not obvious that any terrestrial quarantine facility

Telescopes Mastery

Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

Get My Free Ebook


Post a comment