Ship commissioning

Decommission is the act of withdrawing a ship from active service. In the Federation Starfleet, starships or other vessels that have reached a certain age, become technologically outdated, or have been severely damaged may be decommissioned.

When a vessel is decommissioned, there are a variety of things that may be done with the vessel.
 * It may be sent to a surplus yard, such as Qualor II to either be stripped down or be held in reserve. (TNG episode Unification).
 * It could be dismantled, with its components either scrapped or recycled for use on board other ships or installations. (TOS movie Star Trek III: The Search for Spock and TOS manual Mr. Scott's Guide to the Enterprise).
 * It could be used as a target for live fire exercises. (TOS novel The Ashes of Eden).
 * It may be given to a planetary or regional government for use in a local defense force. (TOS novel The Ashes of Eden).
 * At one time the Federation has sold decommissioned vessels to private entities. (TNG novel Blaze of Glory).

In 2161, the Enterprise (NX-01) was decommissioned after ten years in active service. (ENT episode These Are The Voyages...).

At the completion of the first five year mission under the command of James T. Kirk, Starfleet originally decided to decommission and dismantle the USS Enterprise (NCC-1701)). However the high profile nature of the Enterprise led Starfleet to reverse that decision, and to instead refit the Enterprise. (TOS manual Mr. Scott's Guide to the Enterprise)

In 2285, the age of the Enterprise, coupled with all the recent damage inflicted by Kahn Noonien Singh led Starfleet to decide to finally decommission the Enterprise. Before Starfleet could do so, then Admiral James T, Kirk stole the Enterprise and took it to the Genesis Planet. (TOS movie Star Trek III: The Search for Spock).

After the signing of the Khitomer Accords in 2293, the USS Enterprise (NCC-1701-A) was decommissioned. The vessel was soon handed over to the government of Chal for use in their local defense force. She was later destroyed by Admiral Drake. (TOS novel The Ashes of Eden).

For some time, the Federation sold old, outdated starships to private concerns. There was at least one old Constitution class starship that was sold in such a manner. This vessel eventually fell into Romulan hands, where it had been refitted and given to the privateer Deigo DeBlazio to attack Federation shipping. (TNG novel Blaze of Glory).