Rocket Science for Couch Potatoes: Space Propulsion

Space Propulsion System: Learn How They Work

Ever wondered how spaceships zoom through the inky blackness of space? Unlike airplanes that rely on wings and air, these incredible machines use a powerful concept called rocket propulsion. To understand space travel, you need to know about the space propulsion system.

So buckle up, because we’re about to dive into the science behind this mind-blowing technology!

Basics of Spacecraft Propulsion

The Flat Earth Theorists often claim that propulsion can’t work in a vacuum, so space travel isn’t real. USA Today has already debunked this claim and explained with evidence how rocket propulsion is real and works within the laws of physics.

For a simpler explanation, take this scenario: Imagine holding a balloon filled with air and then letting go. The air shoots out one way, and the balloon zooms in the opposite direction. That’s kind of like a rocket engine. It burns fuel and blasts out hot gas in one direction, and that pushes the spaceship forward in the opposite direction, just like Newton’s third law of motion: for every action, there’s an equal and opposite reaction!

Now, let’s explore the technical side of spacecraft propulsion.

Wikipedia defines spacecraft propulsion as “any method used to accelerate spacecraft and artificial satellites.”

If you’ve noticed closely, whenever a spacecraft maneuvers, it produces an explosion (thrust, more specifically) that takes it in the opposite direction. The same explosion is used to slow it down (while landing on the moon or any surface). This explosion is what the space propulsion systems generate.

This system is made up of multiple components. NASA lists some of them, which are:

Rocket engine

The heart of the system, the rocket engine, is where the magic happens. It consists of several vital parts like the combustion chamber, propellant injection center, powerhead, and the rocket nozzle.

Here’s what they mean:

Combustion Chamber: This is where the propellants (fuel and oxidizer) are injected, mixed, and ignited. Here, a controlled explosion occurs, generating high-temperature, high-pressure gases.

Propellant Injection System: This system precisely delivers the propellants into the combustion chamber at the right pressure and flow rate. It can involve pumps, valves, and injectors.

Powerhead: This sturdy structure houses the combustion chamber and withstands the immense heat and pressure generated within. It’s often made of high-temperature alloys and cooled by circulating propellants (in some designs) to prevent overheating.

Rocket Nozzle: This funnel-shaped section plays a crucial role. It accelerates the hot exhaust gases to incredibly high velocities, converting the thermal energy of combustion into the directed thrust that propels the spacecraft forward. The nozzle’s design is critical for optimizing engine efficiency.

A malfunction in any part of the propulsion system, from pumps to combustion chambers, can lead to engine failure, which prevents the spacecraft or the object from moving forward or the escape velocity. The H-IIA Launch Vehicle No. 6 Japanese launch vehicle suffered a catastrophic engine failure during liftoff. A malfunction in the solid rocket booster led to a loss of control and the explosion of the rocket. Thankfully, there was no crew onboard.

Fuel tanks

This part of the propulsion system holds the fuel, which can be a variety of materials like liquid hydrogen, kerosene, or even solid propellants like ammonium perchlorate.

Propellants

Propellant is the fuel that powers the propulsion system burns. The choice of propellant depends on factors like desired thrust, specific impulse (efficiency), and mission requirements.

The Burning Process

To produce thrust (the force that propels the spacecraft into space), each component works in a coordinated dance. Propellants are fed from the tanks, injected into the combustion chamber, ignited, and then accelerated through the nozzle, generating thrust. During takeoff, rockets can consume as much as 11,000 pounds of fuel per second!

And the energy generated can equal the energy of 13 Hoover Dams operating concurrently. This thrust propels the spacecraft forward. The specific design of each component (engine type, nozzle shape, propellant choice) is carefully chosen to optimize the system for the mission’s specific needs.

The Propulsion Systems of Tomorrow

The biggest challenges in space missions today revolve around the energy and fuel needed for launching, transferring orbits, and maneuvering spacecraft or satellites in space. We’re working on creating propulsion systems that offer more power, better reliability, and are kinder to the environment, all while keeping costs down. These are the hurdles we need to overcome to push space exploration forward.

Today, we have two main types of rocket engines: liquid engines and solid rockets. The liquid engines power workhorses like SpaceX’s Falcon 9 and the European Ariane 5 rockets. Solid rockets are usually employed as launch assisters and in military missiles.

But the future belongs to electric propulsion and nuclear thermal rockets. Ion propulsion is being tested for the NASA Evolutionary Xenon Thrusters (NEXT) and the Annular Ion Engine (AIE). The American space agency is also working on RDRE, or Rotating Detonation Rocket Engine, which consumes less fuel while producing more thrust!

So, the future of deep space travel looks bright and sustainable!

Sources:

Figure 1. The parts of liquid rocket engine. (n.d.). ResearchGate. https://www.researchgate.net/figure/The-parts-of-liquid-rocket-engine_fig1_320628712

H-IIA Launch Vehicle No.6 Why did the accident happen? (n.d.). https://global.jaxa.jp/article/special/h2a6/index_e.html#:~:text=6%20(H%2DIIA%20F6),and%20velocity%20to%20reach%20orbit.

How does a rocket work in space where there is no air to push against? | Science Guys | Union University, a Christian College in Tennessee. (n.d.). https://www.uu.edu/dept/physics/scienceguys/2002Sept.cfm

NASA Glenn Research Center. (2023, November 20). Propulsion System | Glenn Research Center | NASA. Glenn Research Center | NASA. https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/propulsion-system/#:~:text=The%20propulsion%20of%20a%20rocket,the%20air%20and%20through%20space

National Aeronautics and Space Administration & Marshall Space Flight Center. (2005). Space Shuttle Propulsion Trivia. In NASA Facts (Press-Release FS-2005-04-027-MSFC Pub 8-40380). https://www.nasa.gov/wp-content/uploads/2016/08/113069main_shuttle_trivia.pdf

Today, K. S. P. U. (2022, November 30). Fact check: Rocket propulsion functions in space because of universal physical laws, no air required. USA TODAY. https://www.usatoday.com/story/news/factcheck/2022/11/30/fact-check-yes-rocket-propulsion-works-space-despite-lack-air-newtons-law/10766171002/

Verma, R. (2023, January 30). Nasa’s new rocket engine could shorten the journey time to Mars and Moon: A game-changer for deep space exploration | Business Insider India. Business Insider. https://www.businessinsider.in/science/space/news/nasas-new-rocket-engine-could-shorten-the-journey-time-to-mars-and-moon-a-game-changer-for-deep-space-exploration/articleshow/97441618.cms

Wikipedia contributors. (2024, July 19). Spacecraft propulsion. Wikipedia. https://en.wikipedia.org/wiki/Spacecraft_propulsion