Process
The risk of forward-contamination by terrestrial micro-organisms depends on their ability to survive the voyage and on the environmental conditions they find on arrival. The spacecraft must be sterilized before leaving Earth in order to minimize the risk of depositing Earth-originating biological material at the destination. Heat energy, administered in the form of an elevated temperature heat soak over a specific interval of time, is a well-known method for inactivating organisms. Clean room assembly and microbial reduction through heat, chemicals or radiation are the basic techniques used to accomplish microbial control when this is necessary for a mission. NASA currently has only one approved method – dry heat microbial reduction. This technique was used on the Viking Mars landers, which were built and launched in the 1970s. Advanced materials, electronics, and other heat-sensitive equipment being used on spacecraft today could be damaged by such high-temperature treatment, however. Consequently, NASA researchers are developing an alternative sterilization method, a low-temperature, vapor-phase, hydrogen peroxide-based sterilization process. The certification process to support this goal is lengthy and requires substantial fundamental research and method standardization. Two methods being considered for near-term submission to NASA for use on spacecraft are Limulus Amebocyte Lysate assay, and Adenosine Triphosphate assay.
Read more about this topic: Planetary Protection
Famous quotes containing the word process:
“Language is a process of free creation; its laws and principles are fixed, but the manner in which the principles of generation are used is free and infinitely varied. Even the interpretation and use of words involves a process of free creation.”
—Noam Chomsky (b. 1928)
“Any balance we achieve between adult and parental identities, between children’s and our own needs, works only for a time—because, as one father says, “It’s a new ball game just about every week.” So we are always in the process of learning to be parents.”
—Joan Sheingold Ditzion, Dennie, and Palmer Wolf. Ourselves and Our Children, by Boston Women’s Health Book Collective, ch. 2 (1978)
“A process in the weather of the world
Turns ghost to ghost; each mothered child
Sits in their double shade.
A process blows the moon into the sun,
Pulls down the shabby curtains of the skin;
And the heart gives up its dead.”
—Dylan Thomas (1914–1953)