The recent static fire of the Falcon Heavy Rocket on January 24th got m thinking more about SpaceX and how the company has revolutionized space flight. While NASA continues to pay SpaceX for launches to the ISS, they also continue to invest money and time into developing the Space Launch System (SLS) lead by Boeing to replace the space shuttle. But back to the static fire. SpaceX fired all 27 merlin engines of the Falcon Heavy on the launch pad as a final test before the maiden launch of the Falcon heavy.
This reminded me about how i have yet to write about the launches or landings of Falcon 9, and the little i could explain of the launch and reuse of first stage rockets.
First, the ignition of the Falcon 9's 9 merlin engines provide 7,607 kN (1,710,000 lbs) of thrust to launch the rocket. As the gases from the liquid oxygen and kerosene fuels leave the engines, it exerts force on the Earth which then pushes the rocket off the ground by Netwon's third law of motion. For every action there is an equal and opposite reaction.
Then, while rising up through the atmosphere and upon return to the adorably named, "Of Course I Still Love You" drone ship, the rockets first stage experiences drag forces. Upon launch, the rocket must be able to overcome these forces and upon re-entry, not burn up. The Falcon 9 first stage carries extra fuel to to fire the engine for a landing burn above the drove ship to counter act the rockets combined kinetic energy and gravitational potential energy. The rocket also has fins attached that open upon decent to apply drag to the rocket to steer and slow down.
This process of landing first stages and reusing them has cut the cost of SpaceX launches dramatically and has still had its fair share of failures, enjoy.