Editing Rocket (section)

==Safety, reliability and accidents==
{{See also| List of spaceflight-related accidents and incidents}}
{{Expand section|date=May 2016}}
[[File:Challenger explosion.jpg|thumb|{{OV|99}} torn apart T+73 seconds after hot gases escaped the [[Solid rocket booster|SRBs]], causing the breakup of the Shuttle stack]]
The reliability of rockets, as for all physical systems, is dependent on the quality of engineering design and construction.

Because of the enormous chemical energy in [[rocket propellant]]s (greater energy by weight than explosives, but lower than [[gasoline]]), consequences of accidents can be severe. Most space missions have some problems.<ref name="Janes">{{cite web |url=http://www.janes.com/aerospace/civil/news/jsd/jsd030203_3_n.shtml|title=A brief history of space accidents|date=2003-02-03|publisher=Jane's Civil Aerospace|access-date=2010-04-24|archive-url=https://web.archive.org/web/20030204073904/http://www.janes.com/aerospace/civil/news/jsd/jsd030203_3_n.shtml|archive-date=2003-02-04}}</ref> In 1986, following the [[Space Shuttle Challenger disaster|Space Shuttle ''Challenger'' disaster]], American physicist [[Richard Feynman]], having served on the [[Rogers Commission]], estimated that the chance of an unsafe condition for a launch of the Shuttle was very roughly 1%;<ref>{{cite web |url=http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commission/Appendix-F.txt |title=Rogers commission Appendix F |access-date=2012-12-10 |url-status=live |archive-url=https://web.archive.org/web/20120911052800/http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commission/Appendix-F.txt |archive-date=2012-09-11 }}</ref> more recently the historical per person-flight risk in orbital spaceflight has been calculated to be around 2%<ref>{{cite web |url=http://www.space.com/missionlaunches/spacetourism_future_040930.html |title=Going Private: The Promise and Danger of Space Travel By Tariq Malik |publisher=Space.com |date=2004-09-30 |access-date=2012-12-10 |url-status=live |archive-url=https://web.archive.org/web/20110107124459/http://www.space.com/missionlaunches/spacetourism_future_040930.html |archive-date=2011-01-07 }}</ref> or 4%.<ref name=SpaceReview>{{cite web |url=http://www.thespacereview.com/article/36/2|title=Weighing the risks of human spaceflight|publisher=[[The Space Review]]|date=21 July 2003|access-date=1 December 2010|url-status=dead|archive-url=https://web.archive.org/web/20101123233332/http://www.thespacereview.com/article/36/2|archive-date=23 November 2010}}</ref>

In May 2003 the astronaut office made clear its position on the need and feasibility of improving crew safety for future NASA crewed missions indicating their "consensus that an order of magnitude reduction in the risk of human life during ascent, compared to the [[Space Shuttle]], is both achievable with current technology and consistent with NASA's focus on steadily improving rocket reliability".<ref>{{Cite book|last1=Fragola|first1=J.|last2=Baum|first2=J.D.|last3=Sauvageau|first3=D.|last4=Horowitz|first4=S.J.|title=RAMS '06. Annual Reliability and Maintainability Symposium, 2006 |chapter=Reliability and crew safety assessment for a solid rocket booster/J-2S launcher |date=January 2006|chapter-url=https://ieeexplore.ieee.org/document/1677430|pages=545–550|doi=10.1109/RAMS.2006.1677430|isbn=1-4244-0007-4|s2cid=22788307}}</ref>