In Star Trek VI: The Undiscovered Country, the destruction of my namesake Praxis causes an ecological disaster on the Klingon homeworld and paves the way for a serious peace effort between the Federation and the Klingon Empire. Spock, addressing the Commander-in-Chief of Starfleet, a collection of admirals, and the senior officers of the Enterprise A, claims:

The Klingon Empire has roughly fifty years of life left.

More specifically, the Federation President makes the following pledge to diplomats at the Khitomer Conference:

The proposed agenda is as follows: the total evacuation of Kronos has been calculated within the fifty Earth year time span. Phase One: preparation for evacuation....

This was in 2293. However, from Next Generation episodes, we see that the Klingon High Command is still based on Qo'noS in the 2360s.

Was Qo'noS actually evacuated? If so, was the evacuation only temporary? If it was never evacuated, then what caused the plan to change?

  • 2
    The location, description ("ecological disaster"), and just barely the timing ("late 23rd century" vs "after 2293") fits the Great Tribble Hunt, but I don't know if they've been explicitly tied together. Doesn't really fit the moon's destruction, though
    – Izkata
    Commented Mar 1, 2015 at 5:52

3 Answers 3


According to the Memory Alpha article on Qo'noS, the destruction of Praxis resulted in planning for evacuation of Qo'noS and led to the signing of the first Khitomer accord.

The article on Praxis gives some more background information on the disaster. It says the destruction of the moon polluted the Ozone of Qo'noS and that the Klingons lacked the resources to deal with this because of their military spending which is why Gorkon reached out to the Federation.

Nothing has been ever said canonically regarding a mass evacuation or return to Qo'noS but it does seem that there were more Klingons living offworld in the TNG era than in the TOS era so it's possible. For example, some time between Enterprise and TNG, the Klingons colonized Krios and supplanted its monarchy with a Klingon governor. They also had colonies at Khitomer and Narendra III which both had major roles in TNG era plot lines.

Alternatively, nothing has ever been said that indicates those colonies didn't exist long before the 24th century or that they were established after Qo'noS was evacuated so it's equally possible that the Federation was able to help stabilize the atmosphere of Qo'noS following the Praxis disaster and any new colonization was simply imperial expansion on the part of the Klingons.


An evacuation is never explicitly confirmed. There are no artifacts that would confirm a mass evacuation. Star charts are not updated, no strategic advantage is lost or gained for the empire, physical architecture of cities and the ancestral homes of great houses all seem to have remained constant.

Unlike the Romulans the Klingons seem to be completely unaffected by this part of their history except for the events of Star Trek VI.

3 possibilities remain.

A. Klingons are extremely resilient. Despite the ongoing political sparring between great houses they endured.

B. Although never mentioned, perhaps the federation was able to develop technology to limit or reverse the damage from the praxis explosion.

C. Script writers are lazy.

"Probably a a little of A and B" - Lazy script writer


Star Trek VI indicates that the plan was for the Klingons to abandon Qo'nos (and possibly all the rest of their empire) and for many to migrate into Federation space and settle on planets within the Federation, possibly as Federation citizens and possibly as citizens of independent realms.

In one TNG episode Wesley says that the Klingons joined the Federation, which is probably partially correct, and the Klingons in the episode "Heart of Glory" might belong to a Klingon realm which is a Federation member.

In "Yesterday's Enterprise" it is shown there is at least one independent Klingon realm and it is large enough to fight a long war with the Federation. In "Sins of the Father" the Enterprise visits a planet called Qo'nos, which has the same name as Qo'nos in Star Trek VI and may or may not be the same planet, which is the the capital of "The Klingon Imperial Empire".

"The Klingon Imperial Empire" seems to be the mighty independent Klingon realm that is seen in all later Klingon episodes of TNG. DS9, and Voyager. There is no information about how much its territory overlaps with that of the Klingon Empire previous to Star Trek VI.

The name "The Klingon Imperial Empire" seems to imply the existence of other Klingon realms which may have names like "The Klingon Imperial Republic",The ""Klingon Royal Republic", "The Klingon Democratic Empire", "The Klingon Republican Empire", "The Klingon Socialistic Empire", etc., etc. Some of these hypothetical Klingon realms might be members of the Federation, The Romulan Empire, and other major powers and some of them might be minor independent realms.

Clearly there was a lot of Klingon history between Star Trek VI and TNG and nobody knows how much of the Star Trek VI plan was accomplished.

  • 2
    The concensus of opinion is that Wesley meant that the Klingons had become allied to the Federation, rather than joining the Federation proper.
    – Valorum
    Commented Mar 25, 2015 at 21:02
  • Richard - the concensus of opinion may be correct. I prefer to interpret everything as literally as possible, and I think it would be closer to the obvious meaning of Wesley's words to believe that (only some of) the Klingons joined the Federation at one time instead of there being only one Klingon realm which merely became allied to the Federation. Commented Mar 28, 2015 at 5:37
  • Wesley's statement has been repeatedly contradicted, even within the same series.
    – Valorum
    Commented Mar 28, 2015 at 9:26
  • Richard - When person A says that members of ethic group B joined Realm C, while other episodes show that members of ethic group B rule realm D, the logical assumption is that both are partially correct, and that some members of ethic group B (the Klingons) joined Raalm C (The Federation) and others maintain a separate realm D (The Klingon Imperial Empire). Isn't it true that ever since 1870 most Germans have been citizens of their ethnic realm Germany while many others have been citizens of multi-ethnic realms such as Austria and Switzerland? Commented Mar 28, 2015 at 21:00
  • You can endlessly argue this one. It's clear from subsequent episodes that the Klingon Empire is not a member of the Federation. You can ask it as a separate question if you want though...
    – Valorum
    Commented Mar 28, 2015 at 21:05

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