SpaceX
What Is Falcon 9? SpaceX's Workhorse Rocket, Explained
Falcon 9 is SpaceX's workhorse rocket and the first to land and fly again. Here's how it works, why it's reusable, and what it launches.
Falcon 9 is the workhorse rocket of SpaceX — a partially reusable, two-stage rocket that has become the most frequently flown launch vehicle in the world. Its game-changing trick is that the big, expensive bottom half flies back to Earth and lands intact, so it can be cleaned up and launched again. That reusability is the main reason getting to space has gotten dramatically cheaper.
Why it’s called Falcon 9
The name comes from its engines: the first stage is powered by nine Merlin engines (the “9”), firing together at liftoff. The “Falcon” is a nod to the Millennium Falcon. Those nine engines also give it a safety margin — it can still complete some missions even if one underperforms.
How Falcon 9 works
Like most rockets, it flies in stages:
- First stage. The nine-engine booster does the heavy lifting off the pad, then separates, flies back and lands to be reused. This is the reusable part.
- Second stage. A single engine takes over to carry the payload the rest of the way to orbit. This part is not recovered.
Stacking stages lets the rocket shed dead weight as it climbs, which is far more efficient than hauling everything to orbit.
What it launches
Falcon 9 is remarkably versatile. It lofts satellites for commercial and government customers, carries batches of SpaceX’s own Starlink internet satellites, and launches the Dragon spacecraft with cargo and astronauts. Its high flight rate makes it the backbone of much of the world’s access to orbit.
Reusability changed everything
Before Falcon 9, rocket boosters were used once and discarded. Landing and reflying the first stage slashed the cost per launch — the mechanics of which we cover in how SpaceX lands rockets and what it means for the price in how much a SpaceX launch costs.
FAQ
What is Falcon 9 used for?
It launches satellites, batches of Starlink internet satellites, and the Dragon spacecraft carrying cargo and astronauts to the International Space Station. It’s SpaceX’s main rocket.
Why is it called Falcon 9?
Because its first stage uses nine Merlin engines. The “Falcon” part is a reference to the Millennium Falcon from Star Wars.
Is Falcon 9 reusable?
Partly. The first-stage booster lands and is reused many times, which lowers launch costs. The smaller second stage is not recovered.
How many engines does Falcon 9 have?
Ten in total: nine Merlin engines on the first stage and one vacuum-optimized Merlin on the second stage.
Spaceflight hardware and flight rates evolve over time. This explainer covers the durable basics and is reviewed periodically.