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Rocket Science for Couch Potatoes: Reusable Rockets

August 07, 2024

Rocket Science for Couch Potatoes: Reusable Rockets in the Space Industry: A Short, Simple Explainer - V 1.0

Blast off into the fascinating world of space with our series on foundational concepts. We are starting this series of newsletters with the game-changing innovation of reusable rockets.

Have you ever wondered about the marvel of reusable rockets? Their development is as groundbreaking as NASA's first manned moon landing. Why, you ask? Because just like skeptics who think NASA faked the moon landing, there are a sizeable number of folks who think Elon and his SpaceX team faked their reusability rockets.

But why do the skeptics make such tall claims? In SpaceX's case, it's the seemingly impossible task of creating such a rocket in the first place.

So, in this article, let's learn how reusable rockets in the space industry work and what the future holds.

Launch Vehicles: A Detailed Look

"Rocket" is a generalized term. Even missiles are colloquially called rockets. In the space industry, when referring to reusable rockets, you should use the term "launch vehicles." Alternatively, some – like the Saturn V rocket – are called "Heavy Lift Vehicles." But in this article, we'll be using launch vehicles and rockets interchangeably for simplicity.

A launch vehicle consists of multiple independent components. You'd be surprised to learn that a majority of the components go to waste after use. As illustrated in this Anatomy of a Rocket example by California Academy of Sciences, the payload (the part that carries the cargo or astronauts) is a relatively small component. The rest of the components, which go wasted, are:

Stage 1 – The bottommost part of the rocket that contains the main engines. It lifts the entire structure from the launch pad up until the orbit.

Stage 2 – The penultimate section of the rocket from the bottom that houses the secondary engines. It takes over after the rockets enter and exit the earth's orbit.

Stage 3 – The third section of rockets is used when there's a massive payload. It's not uncommon for rockets to weigh more than 400 elephants on average!

Boosters – Boosters are smaller rockets that work in conjunction with the rockets to take the structure into outer space.

Engines – Engines are located at the end of each rocket stage and produce the explosion.

Fins – While not needed, some rockets employ fins to steer the structure in the earth's atmosphere.

How do Reusable Rockets Work?

Most, if not all, are multi-stage rockets. They are ideal for achieving high orbital velocities needed to escape earth's gravity and reach space. Each stage acts like a separate fuel tank and engine combo.

Once the first stage reaches a certain altitude and velocity, it separates from the upper stages carrying the payload. This separation can be achieved through explosive bolts or pneumatic systems. As the propellant in a stage is depleted, it's jettisoned, reducing the overall weight and allowing the remaining stages to reach higher speeds.

In the traditional setting, the depleted stage components are directed towards the ocean where they get deposited at the ocean floors.

But reusable rockets bring the components back to earth and use them again for other space flights. While technically used stages can be flown back to the launchpad, companies like SpaceX opt to land them on the ocean and have them ship back to land.

There are two main approaches to landing reusable first stages:

Powered Descent and Landing: This technique, used by SpaceX's Falcon 9 and Falcon Heavy, involves reigniting some of the first stage engines during descent for a powered landing. The rockets use fins, known as Grid fins, on the stage, which provide control during this phase, guiding it back to a designated landing pad or drone ship.

Propulsive Pogo and Parachute Landing: This method, being explored by Blue Origin's New Glenn, uses a single engine for short bursts during descent for course correction while relying primarily on parachutes for the majority of the slowdown. The vehicle then lands on a designated pad.

After a successful landing, the reusable stage is recovered and undergoes a thorough inspection and refurbishment process. This may involve repairs, cleaning, and engine checks before it can be prepped for another launch.

The Future: Fully Reusable Rockets

Today's technology enables some parts of the rocket to be recovered and reused. The Space Shuttle recovered its RS-25 engines, solid rocket boosters, and the Space Shuttle orbiter, among other components. Likewise, the SpaceX Falcon recovered its First Stage booster, while the Second Stage was expended.

As per reports, the global reusable launch vehicle market is projected to reach USD 4.9 billion by 2030, growing at a compound annual growth rate (CAGR) of 11.71% during the forecast period.

The goal for the future is to recover all the components and reuse them over and over again. In addition to SpaceX and NASA, Blue Origin is actively working on reusable rockets. Blue Origin’s reusable launch vehicles and in-space systems are safe, cost-effective, and tailored to meet the needs of civil, commercial, and defense customers. a company working towards this goal other than SpaceX and NASA. Fully reusable rockets are expected to become the standard for space launches in the future.

References:

Cosmos Magazine. (2021, August 26). Reusable rockets explained. Cosmos. https://cosmosmagazine.com/space/launch-land-repeat-reusable-rockets-explained/

Global Reusable Launch Vehicle Market Size, Share Forecast 2030. (n.d.). Spherical Insights. https://www.sphericalinsights.com/reports/reusable-launch-vehicle-market

Guerrieri, G. (2023, February 8). Reusable Rockets: the History and Progress - impulso.space. impulso.space. https://impulso.space/blog/posts/reusable-rockets/

Koebler, J. (2016, April 13). Meet the truthers who are certain SpaceX faked its rocket landing. https://www.vice.com/en/article/nz7e4z/meet-the-truthers-who-believe-spacex-faked-its-rocket-landing

May, S. (2024, June 3). What was the Saturn V? (Grades 5-8) - NASA. NASA. https://www.nasa.gov/learning-resources/for-kids-and-students/what-was-the-saturn-v-grades-5-8/