Praxis
Praxis was a natural moon of the Klingon homeworld, Qo'noS. It was the only moon of that planet and was inhabited. Praxis was used as the Klingon Empire's key energy-production facility in the 23rd century. (; ; )

History 
In 2293, Praxis was destroyed in a large explosion caused by over-mining and insufficient safety precautions. The explosion caused a powerful subspace shock wave and deadly pollution of Qo'noS' ozone, threatening the depletion of the oxygen in that planet's atmosphere within approximately fifty Earth years. 

Returning from a mission in the Beta Quadrant, the  experienced the shock wave and determined that Praxis had exploded. Sulu sent a communique offering assistance. A reply was sent by Brigadier Kerla, who reported that there was an incident on Praxis but refused Excelsior's assistance, ordering them to obey treaty stipulations and remain outside the Neutral Zone.

Praxis' destruction resulted in significant political change, as the Empire had to divert resources from their vast military budget to address the environmental change. Chancellor Gorkon realized that they could not afford hostilities with the  and approached the Federation with an overture of peace. This set into motion a series of events, eventually resulting in a lasting peace between the Federation and the Empire through the Khitomer Accords. (; )

People

Appendices

Background information 
The explosion of Praxis was loosely based on the , one of several factors leading to the breakdown of the Soviet Union. (Captains' Logs: The Unauthorized Complete Trek Voyages, pp. 137-138) Likewise, the word "Praxis" is employed in the writings of , meaning active rather than merely theoretical .

Praxis' destruction in Star Trek VI (particularly its placement at the start of the film) was influenced by a clap of thunder that begins Macbeth. In the playwright workshop at the , Nicholas Meyer (who co-wrote the screenplay of Star Trek VI and directed the film) learned it was a very effective method of attracting an audience's attention to the story. (audio commentary, Star Trek VI: The Undiscovered Country (Special Edition) DVD)

In a scripted line not included in the actual film, Praxis was to have been established as having no indigenous lifeforms.

In the script of "Flashback" (both the first draft and the final draft of the teleplay), Praxis was at first referred to as "the primary source of energy for the Klingon Homeworld." On screen, however, Tuvok instead says this line slightly differently, referring to Praxis as merely "a primary source of energy for the Klingon Homeworld," which is also how the closed captioning notates the line.

Praxis has become the namesake of the , the distinctive type of special effect in which a space explosion produces two-dimensional waves.

Praxis (system) 

In the star charts seen in several  episodes – , ,  and  – there was a star system named Praxis in Klingon territory. This system was first referenced in the reference works Star Trek: Star Charts (p. 61) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"). In the star chart seen in the  episode , the Praxis system was not depicted on the map. This reflected one of the changes made for the revised edition of the Stellar Cartography: The Starfleet Reference Library.

Apocrypha 
In the Star Trek: Myriad Universes story , set in an alternate timeline (specifically, one from  in which Spock died as a child), Praxis is chosen by Thelin in 2290 as the test site for the Genesis Device (which in this timeline had led to full-scale war), both as a demonstration of force and because, with nearly all of its inhabitants living in areas either underground or shielded, there would be little or no loss of life. The action forces the Klingons to surrender; unfortunately, the Genesis Wave overwhelms most shields and reaches below the ground, and of the population of half a million, only 2,000 survive. However, during peace negotiations, it is discovered that Genesis actually saved the moon, as the explosion which occurred in the prime universe had been inevitable within a year before the wave had strengthened the planet and put an end to the mining that would eventually destroy it.

In the   by A.C. Crispin, in addition to polluting Qo'noS' atmosphere, Praxis' explosion has created a ring of debris around the planet that subjects the surface to constant, and sometimes deadly, meteor showers, which also makes space traffic to and from the planet extremely dangerous – another reason why the planet is becoming uninhabitable.

In Star Trek Online, Praxis is presented as the former moon of Qo'noS. After events that occur prior to the year 2409 broke the Khitomer Accords, mining on the remnants of Praxis renewed. The remnants of Praxis orbiting Qo'noS are collectively referred to as the Praxis Belt.

External link 
 

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Moons