Editing Atmospheric entry (section)

==Terminology, definitions and jargon==
{{Hatnote|Over the decades since the 1950s, a rich technical jargon has grown around the engineering of vehicles designed to enter planetary atmospheres. It is recommended that the reader review the [[wikt:Appendix:Glossary of atmospheric reentry|jargon glossary]] before continuing with this article on atmospheric reentry.}}
[[File:Typical Space Shuttle reentry profile.gif|thumb|Typical [[Space Shuttle]] reentry profile]]

When atmospheric entry is part of a spacecraft landing or recovery, particularly on a planetary body other than Earth, entry is part of a phase referred to as ''entry, descent, and landing'', or EDL.<ref>{{Cite web|url=http://www.nasa.gov/pdf/501326main_TA09-EDL-DRAFT-Nov2010-A.pdf|title=NASA.gov|access-date=April 9, 2015|archive-date=February 20, 2017|archive-url=https://web.archive.org/web/20170220165240/https://www.nasa.gov/pdf/501326main_TA09-EDL-DRAFT-Nov2010-A.pdf|url-status=live}}</ref> When the atmospheric entry returns to the same body that the vehicle had launched from, the event is referred to as '''reentry''' (almost always referring to Earth entry).

The fundamental design objective in atmospheric entry of a spacecraft is to [[Dissipation|dissipate]] the <!-- kinetic plus potential -->[[Mechanical energy|energy]] of a spacecraft that is traveling at [[hypersonic speed]] as it enters an [[planetary atmosphere|atmosphere]] such that equipment, cargo, and any passengers<!-- using "passengers" rather than "crew" as, increasingly after 2020, we are seeing a transition in spacecraft designs for vastly more passengers than crew --> are slowed and land near a specific destination on the surface at zero velocity while keeping stresses on the spacecraft and any passengers within acceptable limits.<ref name=nasa197203>{{cite conference |last1=Graves |first1=Claude A. |last2=Harpold |first2=Jon C. |title=Apollo Experience Report – Mission Planning for Apollo Entry |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720013191.pdf |conference=NASA Technical Note (TN) D-6725 |date=March 1972 |quote=The purpose of the Apollo entry maneuver is to dissipate the energy of a spacecraft traveling at high speed through the atmosphere of the earth so that the flight crew, their equipment, and their cargo are returned safely to a preselected location on the surface of the earth. This purpose must be accomplished while stresses on both the spacecraft and the flight crew are maintained within acceptable limits.|access-date=October 25, 2019 |archive-date=October 25, 2019 |archive-url=https://web.archive.org/web/20191025121155/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720013191.pdf |url-status=live }}</ref> This may be accomplished by [[propulsion|propulsive]] or [[Drag (physics)|aerodynamic]] (vehicle characteristics or [[parachute]]) means, or by some combination.