r/SpaceXMasterrace

A SpaceX Starship (upper stage)/Super Heavy (booster) launch consumes an enormous amount of chemical energy—on the order of tens of petajoules.

The Raptor engines burn methane and oxygen in a staged-combustion cycle. SpaceX currently lists approximately 3,650 metric tons of propellant for Super Heavy and 1,600 tons for Starship, or about 5,250 tons total when fully loaded. This consists of approximately 1,140 tons of methane and 4,110 tons of liquid oxygen.

 How much energy is that?

Methane contains roughly 50 MJ/kg of chemical energy. The Starship/Super Heavy carries about 1.14 million kg of methane or approximately 57 petajoules (PJ) of chemical energy. That's about:

·       15.8 terawatt-hours (TWh) of chemical energy or 15.8 billion kWh

 The 57-PJ figure is equivalent to about 1.8 years of continuous electricity generation from a 1-GW power plant, a relatively large generating plant.

A striking comparison is the scale implied by SpaceX's proposed launch rate: At 145 Starship launches per year, the chemical energy released would total approximately 8.3 exajoules (EJ) per year—equivalent to the energy produced by a continuous 1-GW thermal power source operating for about 262 years.

 Where does that energy end up?

The energy released by the rocket is initially distributed among:

·       kinetic energy and potential energy of the exhaust and rocket

·       heat in the combustion products

·       atmospheric heating and turbulence

·       aerodynamic drag, gravitational losses

·       acoustic energy and other smaller energy pathways

Ultimately, most of the chemical energy released by the rocket will be degraded into low-grade thermal energy. Energy initially carried as rocket and exhaust kinetic energy, atmospheric motion, turbulence, and other forms is eventually dissipated as thermal energy within the Earth system, while some energy is ultimately radiated away from Earth as infrared radiation.

 A more consequential environmental effect of Starship launches isn't the direct heat from combustion. Starship's exhaust is primarily CO₂ and water vapor, with smaller amounts of CO, NOx, and particulate material. These combustion products—including water vapor and particles—are injected directly into the upper atmosphere, where their radiative and chemical effects can be substantially different from those of emissions released near the Earth's surface.