This was an important consideration, since the SRB O-rings had been designated as a "Criticality 1" component, meaning that there was no backup if both the primary and secondary O-rings failed, and their failure could destroy the Orbiter and kill its crew.
Aceasta era o considerație importantă, deoarece O-ringurile propulsoarelor fuseseră proiectate drept componentă „Criticality 1”—adică nu exista rezervă în cazul defectării O-ringurilor primar și secundar, iar defectarea lor putea distruge vehiculul și echipajul acestuia.