Credit: SpacecoasterVBG licensed under CC BY-SA 4.0

It’s been more than 10 years since the Falcon 9 launched into space, and the spacecraft has gone through a lot of advancements since then. Not only did it become the first spacecraft to send as many as 143 small satellites into a polar orbit last year, but it was also durable enough to fulfil some of SpaceX’s goals for the Falcon 9 — to be low-cost and partially reusable for future missions. Last August 6, engineers were even able to use one of its first-stage boosters for the sixth time, setting a new record for booster reuse.
And while it’s mainly used to deliver cargo payloads, the Falcon 9 is now capable of sending humans to orbit. Sometime in September, another human-boarded launch is set.
Today, we take a look at how this spacecraft was created.

A low-cost, high-quality spacecraft

The Falcon 9 is a two-stage spacecraft. The first stage is powered by nine Merlin engines, and the second one with one Merlin vacuum engine. Since June 2020, the rocket has launched 84 times and has safely returned 45 times. 31 of the rockets that have failed to take off were recycled and launched again, which contributed to the Falcon 9’s lowered costs.
Moreover, the Falcon 9 uses a lot of redundant components, such as the Merlin engines, as well as conventional processors, which could have made the entire thing very tedious and expensive to build. But by creating these 3D components in a footprint library, Falcon 9 designers could automate the process and standardize the quality of their components. CAD tools have also enabled them to integrate mechanical design workflows into their electrical design software, reducing the number of design spins needed to complete each part.

Merlin engines

The Merlin is one of the most efficient engines produced. It uses RP-1 and liquid oxygen as rocket propellants, eliminating the need for a separate hydraulic drive system. It has also gone through different versions in more than half a decade. The Merlin variant used for the Falcon 9, Merlin 1D, has about 850 kN of thrust, bringing it close to the power-levels of other notable spacecraft in the industry, like Delta II and Saturn I. Nine of these engines were installed for Falcon 9’s stage one.
On the other hand, stage two was powered by a single Merlin Vacuum (a variant known as “Merlin Vacuum 1C”). Merlin Vacuum 1C has a larger nozzle and exhaust, keeping it energy-efficient even in space. It has a thrust of 411 kN. And Falcon 9 was the only spacecraft to use it.

Launch gear

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It’s not just the materials for the rocket itself that kept the costs down — its launch gear played a huge role as well. For example, the Octaweb structure that protects the Merlin engines reduced the length and weight of Falcon 9 because of a simple engine arrangement. The Octaweb had eight engines surrounding the ninth one, concentrating firepower on one location while keeping the spacecraft’s balance. Meanwhile, SpaceX used a pressurized air separation system for the interstage, eliminating the need for complex and high-cost electronics.
Overall, the Falcon 9 that we have today is a culmination of years of technology. It’s still not perfect; after all, one of its booster tests failed just last February. Still, it’ll be exciting to see what the future has in store for this particular spacecraft.