The #NASA livestream of the cargo Dragon launch is on NASA TV. Launch targeting 8:30 PM EDT from Pad 39A.
@Anton The engines are about to combust RP-1 fuel (ambient temperature) with super-chilled liquid oxygen (about -340°F). If the metals are instantly hit with something that cold, they could fracture or leak. So the engines are slowly chilled to bring down the temperature to withstand the LOX.
They do it for a liquid-fueled rocket using a cold propellant. Solid fueled rockets are just burning something that looks like Play-Doh.
@WordsmithFL Why do they chill the engines? Do they do this for all rockets?