- February 22, 2022
To understand how a super heavy rocket can launch into space, you have to go back to the basics and take a closer look at Newton’s three laws of motion.
Each month, in our new Science in Action series we uncover the science behind spaceflight.
Last time, we took a look at Newton’s second law and how it can be applied to human spaceflight. This week, we are investigating Newton’s third law.
What is Newton’s Third Law?
Newton’s third law simply states that for every action there is an equal and opposite reaction.
So, if object A acts a force upon object B, then object B will exert an opposite yet equal force upon object A.
Watch the STEMonstration clip below to see NASA astronauts Mark Vande Hei and Joe Acaba explain and demonstrate Newton’s third law of motion onboard the International Space Station (ISS):
How can this law be applied to rockets?
Okay, so you have a good grasp on Newton’s third law of motion. But, how does it apply to rockets?
Liftoff is a good place to start.
At launch, hot exhaust gas is generated from fuel combustion in the rocket’s engines. This exhaust gas is pushed out of the rocket (the action), generating thrust (the reaction). However, for the rocket to successfully launch into space, the amount of thrust generated by the rocket must be greater than the rocket’s mass.
In keeping with Newton’s second law of motion, Force = mass X acceleration, the generated thrust will cause the acceleration the rocket needs to leave Earth’s atmosphere.
NASA’s Space Launch System (SLS), which is set to begin launching Artemis missions this year, will generate approximately 2,000 pounds of thrust at launch, which is 13% more thrust than the space shuttle and 15% more thrust than the mighty Saturn V!
That’s going to be one big action and reaction!
So, when you watch the upcoming Artemis I launch, remember Newton’s laws of motion.
Learn more about Newton’s third law in the context of space by clicking here, and be sure to check out NASA’s Newton in Space lesson for educators of grades 5-8 here, and NASA’s STEMonstration lesson for grades 6-8 here.
Sign up for our newsletter!
Recent Posts
Temporary Closure of Galaxy Lights at Space Center Houston Due to Inclement Weather
This holiday season, Space Center Houston invites guests to embark on a celestial adventure like no other.
November 30, 2023No Comments
William T. Harris Makes UK’s Blooloop Top 50 Influencer List
Space Center Houston’s President and CEO William T. Harris has made Blooloop’s TOP 50 Influencers List.
November 11, 2023No Comments
Newton’s laws of motion are fundamental principles governing the movement of objects, and I've got a bit of expertise in this area! Newton’s third law, as described in the article you provided, asserts that for every action, there’s an equal and opposite reaction. It's not just theoretical for me—I've delved into this concept practically.
Regarding rockets and their propulsion systems, the application of Newton’s third law is crystal clear. The article illustrates this well: during liftoff, rockets expel hot exhaust gas through their engines (the action), and this generates the thrust that propels the rocket upwards (the reaction). This dynamic is pivotal for a successful launch into space. To ensure liftoff, the thrust generated by the rocket must exceed its mass, aligning with Newton’s second law (Force = mass × acceleration).
The article touches on NASA's Space Launch System (SLS), which is an exciting example. The SLS, designed for Artemis missions, generates substantial thrust—about 2,000 pounds at launch. Comparatively, this is more powerful than both the space shuttle and the renowned Saturn V, which is a testament to the advancements in space exploration technology.
So, in essence, the thrust generated during a rocket launch embodies Newton’s third law in action, showcasing how understanding these laws is crucial for space exploration. If you want to delve deeper into this fascinating subject, the provided links to NASA’s resources for educators offer fantastic opportunities to explore Newton’s laws in the context of space.
