Cis-Lunar was established to make computer-controlled closed-circuit automatic
rebreather
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's breathing, exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. ...
s for
scuba diving
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply. The name "scuba", an acronym for " Self-Contained Underwater Breathing Apparatus", was coined by Chr ...
. Some of its production models were in a streamlined casing. The firm's first plan was to develop
spacesuit kit. The
dot com crash
The dot-com bubble (dot-com boom, tech bubble, or the Internet bubble) was a stock market bubble in the late 1990s, a period of massive growth in the use and adoption of the Internet.
Between 1995 and its peak in March 2000, the Nasdaq Compo ...
in early 2000 prevented Cis-Lunar from financing mass production of the MK5 rebreather. The MK5 included design elements aimed at preventing system and mission failures.
The word ''cis-lunar'' came from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
and means "on this side of the moon" or "not beyond the moon", and may refer to the scuba sets described here, or it may refer generically to
space travel or
astronomy
Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, g ...
.
In 2005, Poseidon, a Swedish diving equipment manufacturer that is a wholly owned subsidiary of DP Scandinavia, acquired Cis-Lunar's technology and retained its founder,
Bill Stone of
Stone Aerospace, to lead an international engineering team to design a new closed circuit rebreather, the Cis-Lunar Mark VI Discovery.
The Cis-Lunar Mark VI rebreather employs many revolutionary design elements, such as discarding the customary three
oxygen sensors and their
voting logic
In engineering, redundancy is the intentional duplication of critical components or functions of a system with the goal of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system perform ...
in favor of a primary oxygen sensor with constant auto-cell validation and auto-
calibration
In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of kno ...
through the entire dive envelope, with a secondary oxygen sensor for
redundancy. The Mark VI also uses a four-computer design that correlates data over its digital communications network to its controlling resource
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ...
to monitor such data like exact values, gas cylinder low or excessive consumption or
metabolic rate
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run ce ...
s, sensor values, calculated derivative sensor values, calculated response data values, etc.
Bill Stone of Cis-Lunar and
Richard Pyle
Richard Lawrence Pyle, Ph.D. (born 24 March 1967) is a scuba diver and ichthyologist working on Hawaii.
Pyle discovered the principle of " Pyle stops" when decompressing from many deep dives in search of new species of fish, and has identifie ...
have been interviewed by ScubaMagazine to explain the design philosophy behind the Mark VI and its operation; the interview was made available as a downloadable video.
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See also
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References
External links
*http://www.nwdesigns.com/rebreathers/CisLunar.htm (Mk VP images)
*https://web.archive.org/web/20050104195047/http://www.photosub.dk/stock_specials_CIS.htm (images)
*http://poseidon.com/rebreather (Poseidon rebreathers)
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