Up and coming space start-up, Stratolaunch

​​Up and coming space start-up, Stratolaunch, has released new details about a rocket engine they’re developing for future launch vehicles. The PGA engine, named after the founder of the company, will use liquid oxygen and liquid hydrogen propellants with fuel-rich staged combustion – producing a thrust of 200,000 pounds. This engine, the company said, will have the highest specific impulse (measure of efficiency) of any engine to date.