The moment when a rocket engine fires. During a space shuttle launch, this happens at ‘T minus 5 seconds’ (see T) for the three main engines. TIGs are also carefully scheduled for orbit manoeuvres, such as a rendezvous, and for slowing the shuttle so it can drop out of orbit to return. During the latter, the crew's preparations for a deorbit begin at ‘TIG minus four hours’.
Subjects: Astronomy and Astrophysics.