Editing Soyuz (rocket family) (section)

== Launch ==
[[Image:Soyuz 18 booster.jpg|thumb|A [[Soyuz-U]] on the launch pad, ahead of the [[Apollo–Soyuz|Apollo-Soyuz Test Project]] (ASTP) launch on 15 July 1975.]]

The engines are ignited by electrically initiated pyrotechnic flares, mounted on birch poles, which are ignited at approximately T-20 seconds, a few seconds before fuel components are introduced into the combustion chamber.<ref>{{cite web|url=https://www.popularmechanics.com/space/rockets/a19966/russia-actually-lights-it-rockets-with-a-giant-match/|title=Russia Actually Lights Rockets With an Oversized Wooden Match|publisher=Popular Mechanics|first=Anatoly|last=Zak|date=2016-03-17|access-date=2018-08-11}}</ref> This sequence rarely fails due to its simplicity.<ref>{{cite web|url=http://spaceflight101.com/soyuz-resurs-p3/soyuz-rocket-suffers-rare-abort-at-ignition/|title=Soyuz Rocket suffers rare Abort at Ignition – Soyuz {{!}} Resurs-P No.3 {{!}}Spaceflight101|date=12 March 2016 |publisher=spaceflight101.com|access-date=2017-12-04}}</ref> During launch, the support booms track the movement of the rocket. After the support boom heads emerge from the special support recess in the nose sections of the strapons, the support booms and trusses disconnect from the rocket airframe, swiveling on the support axes and freeing the way for the rocket to lift off. During launch, the rocket and the launch facility form a single dynamic system.{{clarify|date=June 2024}}

When the strap-on booster engines stop, the boosters fall away, providing nonimpact separation. If the skies are clear, ground observers can see a [[R-7 (rocket family)#Korolev Cross|Korolev cross]] formed by the falling boosters.