Editing Aerospike engine (section)

{{short description|Type of rocket engine that maintains its aerodynamic efficiency across a wide range of altitudes}}
{{use dmy dates |date=August 2020}}
{{Seriesbox aircraft propulsion}}

[[File:Twin Linear Aerospike XRS-2200 Engine PLW edit.jpg|thumb|upright=1.5|[[Rocketdyne XRS-2200|XRS-2200]] linear aerospike engine for the [[X-33]] program being tested at the [[Stennis Space Center]]]]

The '''aerospike engine''' is a type of [[rocket engine]] that maintains its [[aerodynamic]] efficiency across a wide range of [[altitude]]s.<ref name=factsheet>{{Cite web|url=https://www.nasa.gov/centers/marshall/news/background/facts/aerospike.html|title=NASA - Linear Aerospike Engine fact sheet (08/00)|website=www.nasa.gov|language=en|access-date=2020-01-21|archive-date=18 July 2023|archive-url=https://web.archive.org/web/20230718095241/https://www.nasa.gov/centers/marshall/news/background/facts/aerospike.html|url-status=dead}}</ref> It belongs to the class of [[altitude compensating nozzle]] engines.<ref>{{cite journal|last1=Defusca|first1=Albert|last2=Craddock|first2=Christopher|date=November 1, 2017|title=Affordable Access to Low Earth Orbit|url=https://www.dsiac.org/resources/journals/dsiac/fall-2017-volume-4-number-4/affordable-access-low-earth-orbit|journal=DSIAC Journals|volume=4|issue=4|access-date=June 16, 2019|archive-date=25 December 2021|archive-url=https://web.archive.org/web/20211225092014/https://www.dsiac.org/resources/journals/dsiac/fall-2017-volume-4-number-4/affordable-access-low-earth-orbit|url-status=dead}}</ref> Aerospike engines were proposed for many [[single-stage-to-orbit]] (SSTO) designs. They were a contender for the [[Space Shuttle main engine]]. However, as of 2023 no such engine was in commercial production, although some large-scale aerospikes were in testing phases.<ref>{{Cite web|url=https://www.hq.nasa.gov/office/pao/History/x-33/aerospik.htm|title=Aerospike Engine Homepage|website=www.hq.nasa.gov|access-date=27 August 2020|archive-date=23 May 2022|archive-url=https://web.archive.org/web/20220523204457/https://www.hq.nasa.gov/office/pao/History/x-33/aerospik.htm|url-status=dead}}</ref>

The term ''aerospike'' was originally used for a truncated [[plug nozzle#In rockets|plug nozzle]] with a rough conical taper and some gas injection, forming an "air spike" to help make up for the absence of the plug tail. However, a full-length plug nozzle may also be called an aerospike.