How Do Engineers Design & Build Rockets?4 min read

It seems like NASA and SpaceX are launching rockets every other month, carrying astronauts and supplies to their low Earth orbit destination on the International Space Station. These rockets are marvels of modern engineering, but have you ever wondered what it takes to get half a million kilograms of metal, computers and people off the ground? Let’s take a closer look at how engineers design and build rockets, and what goes into making us a spacefaring species.

1. Planning

An engineer needs to figure out the intended purpose of their new rocket. A cargo rocket will have different specifications — and different safety requirements — than one that needs to ferry astronauts to the ISS or beyond. It needs to meet the needs of the missions while taking off and coming home safely. It might sound simple, but try it for yourself. Kerbal Space Program is a free game that gives you all the tools you need to build and launch a virtual ship. Try it out and see if you can design, develop and launch your own spacecraft.

Once the team of engineers knows what the rocket is for, the next step is to break out a pen and paper and start designing.

2. Design

Step two involves the creation of your rocket. For many engineers, this step starts with good old fashioned pencil and paper to get a basic idea of the size, shape and overall design of the rocket. They may end up with a lot of different designs to choose from before they finally settle on one that will work best for the mission. From there, the team will move to their computers with high-end digital modeling software. This is where things start getting technical. In addition to the design, the eventual blueprints will include everything from the overall height of the rocket to the length, width and thickness of each component.

Rockets may look huge, but they’re designed to maximize space while reducing drag and improving aerodynamics. A Falcon 9, one of SpaceX’s reusable rockets, can carry up to 22,800 lbs into low Earth orbit, but it has to be aerodynamic enough to cut through the planet’s atmosphere and get its payload high enough to reach its destination.

3. Modeling

Stage three involves modeling the rocket. While the engineers may build a couple of small scale models of the finished product, at this point they’re ready to build a full-scale test prototype. These prototypes are fully functional and can undergo all of the necessary testings — up to and including launch tests — preserving the final craft for its mission.

Nearly every spacecraft that we’ve launched since the Apollo program started has had a duplicate on the ground. That was what allowed the ground crew to figure out how to fix problems onboard Apollo 13 and get Jim Lovell, Fred Haise and Jack Swigert home safely. NASA is currently working on building a ground-based duplicate of the planned Gateway Station before it makes its way to orbit around the moon.

4. Testing

Once the models are complete, now comes the testing phase. The engineers put the model through its paces, exposing it to heat, cold, vacuum, radiation and everything it might encounter in the emptiness of space. The results of these tests will run through finite element analysis software to determine any potential failure points. It’ll go through cold-fire tests — where the engine fires but the rocket doesn’t liftoff — and launch/landing tests.

If something fails during these tests, it’s back to the drawing board to figure out why it failed, and how they can keep it from happening during the mission. The whole point of these tests is to make sure each launch will be as successful on mission day as it is during the tests.


Now all that’s left to do is put the rocket up on the launch pad and send it to the stars. SpaceX is working on perfecting reusable rockets that can be ready to go again 24 hours after launch, but they’re not quite there yet — though watching two of the three booster rockets from the Falcon Heavy landing side by side at Cape Canaveral is a sight to behold. The next time you watch a rocket launch — whether it’s NASA, SpaceX or one of the other companies vying for the stars — you’ll have a better appreciation for everything that goes into creating these engineering marvels.

Megan Ray Nichols
Megan Ray Nichols

Megan Ray Nichols Freelance Writer

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