A light informed Aldrin that at least one of the probes hanging from Eagle footpads had touched the surface a few moments before the landing and he said: "Contact light!" Armstrong was supposed to immediately shut the engine down, as the engineers suspected the pressure caused by the engine's own exhaust reflecting off the lunar surface could make it explode, but he forgot. Three seconds later, Eagle landed and Armstrong shut the engine down. Aldrin immediately said "Okay, engine stop. ACA—out of detent." Armstrong acknowledged: "Out of detent. Auto." Aldrin continued: "Mode control—both auto. Descent engine command override off. Engine arm—off. 413 is in."
