backblast area
{{Short description|Area where hot gas is expelled from a recoilless launcher during firing}}
The backblast area is a cone-shaped area behind a rocket launcher, rocket-assisted takeoff unit or recoilless rifle, where hot gases are expelled when the rocket or rifle is discharged.{{cite book|title=Academic Press dictionary of science and technology|url=https://books.google.com/books?id=nauWlPTBcjIC&dq=backblast+area&pg=PA202|pages=202|first=Christopher G.|last=Morris|year=1992|publisher=Gulf Professional Publishing|isbn = 9780122004001}} The backblast area is dangerous to ground personnel,{{cite book|title=U.S. Army Zombie Combat Skills|url=https://books.google.com/books?id=nTlbdMveXwEC&dq=backblast+area&pg=PA112|pages=112|first=Cole G.|last=Louison|year=2009|publisher=Globe Pequot|isbn = 9780762757640}} who may be burned by the gases or exposed to overpressure caused by the explosion.{{cite web|url=https://rdl.train.army.mil/soldierPortal/atia/adlsc/view/public/10880-1/fm/3-22.37/appa.htm |title=Javelin—Close Combat Missile System, Medium, Field manual |publisher=Department of the Army |date=20 March 2008 |accessdate=Sep 3, 2010 |url-status=dead |archiveurl=https://web.archive.org/web/20110720002913/https://rdl.train.army.mil/soldierPortal/atia/adlsc/view/public/10880-1/fm/3-22.37/appa.htm |archivedate=2011-07-20 }} In confined spaces, common in urban warfare, even the operators themselves may be at risk due to deflection of backblast by walls or sturdier civilian vehicles behind them.
Soft launch methods diminish backblast by ejecting the projectile some distance before its main rocket motor ignites. Backblast can also be reduced by adding a countermass that is expelled out the rear of the weapon. For example, the AT4-CS (confined space variant) uses saltwater, along with a lower-velocity projectile. A more current example is NLAW, using a combination of soft-launch and saltwater countermass.{{Cite web |title= NLAW: Next generation Light Anti-tank Weapon |url= https://www.yumpu.com/en/document/read/50782943/nlaw-brochure-saab |url-status=live |archive-url= https://web.archive.org/web/20220323142333/https://www.yumpu.com/en/document/read/50782943/nlaw-brochure-saab |archive-date= 23 March 2022 |access-date=22 March 2022 |publisher=Saab Bofors Dynamics |publication-place= Karlskoga, SE |via= Yumpu}}
File:M72A2 LAW 1969.jpg|Packing crates are used to demonstrate the danger of the M72 LAW back blast
File:A-1 Backblast area and surface danger zone.PNG|Backblast area for FGM-148 Javelin
File:Firing an AT4.jpg|A US Army soldier firing the M136 AT4 (2007)
File:US Army AT4 CS live-fire training.jpg|A US Army soldier firing the AT4-CS (2020)