Unlike strap-on boosters that provide massive, short-lived thrust and are quickly discarded, a sustainer engine fires for a much longer duration. It ignites on the launch pad alongside the boosters and continues to propel the core vehicle after the boosters separate. It is optimized to operate efficiently in both the dense lower atmosphere and the near-vacuum of high altitude.
Booster separation confirmed, the sustainer is burning clean and trajectory is nominal.
Also heard as
- sustainer engine
Related terms
Strap-on
An auxiliary rocket booster attached to the side of a core launch vehicle to provide extra thrust at liftoff.
SRB
A solid rocket booster used to provide heavy initial thrust during a launch.
Interstage
The structural ring or cylinder that connects two stages of a multi-stage rocket.
MECO
Main Engine Cut-Off is the moment during a rocket launch when the primary engines are commanded to shut down.