Editing Deep-submergence vehicle (section)

{{short description|Self-propelled deep-diving crewed submersible}}
[[File:Bathyscaphe Trieste hoisted.jpg|thumb|upright=1.35|In 1960, [[Jacques Piccard]] and [[Don Walsh]] were the first people to explore the [[Challenger Deep|deepest part]] of the world's ocean, and the deepest location on the surface of the Earth's crust, in the [[bathyscaphe]] ''[[Bathyscaphe Trieste|Trieste]]'' designed by [[Auguste Piccard]].]]
[[File:World Deep Submergence Vehicles as of December 2020-1.jpg|thumb|upright=1.35|Historical deep-submergence vehicles]]

A '''deep-submergence vehicle''' ('''DSV''') is a deep-diving crewed [[submersible]] that is self-propelled.{{citation needed|date=January 2023}} Several navies operate vehicles that can be accurately described as DSVs. DSVs are commonly divided into two types: research DSVs, which are used for exploration and surveying, and DSRVs ([[deep-submergence rescue vehicle]]s), which are intended to be used for rescuing the crew of a sunken navy submarine, clandestine (espionage) missions (primarily installing [[wiretaps]] on [[undersea communications cables]]), or both.{{citation needed|date=January 2023}} DSRVs are equipped with docking chambers to allow personnel ingress and egress via a manhole.

Strictly speaking, [[bathyscaphe]]s are not submarines because they have minimal mobility and are built like a balloon, using a habitable spherical pressure vessel hung under a [[liquid hydrocarbon]] filled float drum.{{citation needed|date=January 2023}} In a DSV/DSRV, the passenger compartment and the ballast tank functionality is incorporated into a single structure to afford more habitable space (up to 24 people in the case of a DSRV).

Most DSV/DSRV vehicles are powered by traditional electric battery propulsion and have very limited endurance, while a few (like [[NR-1]] or [[Russian submarine Losharik|AS-12/31]]) are/were nuclear-powered, and could sustain much longer missions. Plans have been made to equip DSVs with [[LOX]] [[Stirling engine]]s, but none have been realized so far due to cost and maintenance considerations. All DSVs to date (2023) are dependent on a surface support ship or a mother submarine that can piggyback or tow them (in case of the NR-1) to the scene of operations. Some DSRV vessels are air transportable in very large military cargo planes to speed up deployment in case of emergency rescue missions.