On Monday, SpaceX launched two Falcon 9 rockets, one carrying 52 Starlink satellites and the other carrying 72 small payloads from different vendors in a “rideshare” mission.
These missions marked SpaceX’s 39th and 40th successful launch this year. Other companies, like Boeing or Blue Origin, can only afford a few launches a year. So, how is SpaceX able to launch so many rockets?
The answer is their revolutionary Falcon 9 Rocket. The Falcon 9 rocket is a medium-sized launch vehicle capable of carrying cargo or crew into Earth’s orbit.
What’s unique about this rocket is that the Falcon 9 is the world’s first orbital-class reusable rocket, allowing SpaceX to launch missions much cheaper than anybody else.
Standing approximately 70 meters tall, the Falcon 9 consists of three main components: the first stage, the second stage, and the dragon capsule (payload).
Let’s dive into each stage to understand the functionality and mechanisms at work.
The First Stage: The Workhorse
The first stage of the Falcon 9 is responsible for the initial thrust required to overcome Earth’s gravity and propel the rocket into space. It uses nine Merlin engines that generate a staggering 1.7 million pounds of thrust together.
These engines run on a combination of cryogenic liquid oxygen (LOX) and a highly refined, rocket-grade kerosene (RP-1) to create a controlled combustion that propels the rocket upward.
At first, the two ingredients are housed in separate tanks in the stage 1 engine.
The two ingredients are pumped into the Merlin engine and ignited, which propels the rocket for approximately 2 minutes and 38 seconds after liftoff before they are shut off and separated from the rest of the spacecraft.
Once the first stage has been separated from the second stage, rather than becoming space debris, the first stage is designed to return to Earth in a controlled descent. The Falcon 9 is equipped with an inertial navigation system (INS) and global positioning system (GPS) that uses various sensors to gauge the booster’s position, orientation, and velocity.
With this information, the onboard computer understands the booster’s location in real-time and checks it against the pre-programmed flight path.
If the computer detects any deviations from the flight path, it instructs the rocket to adjust its position, orientation, and velocity.
To achieve this, the Falcon 9 utilizes a combination of cold gas thrusters, grid fins, and engine reignition in a series of controlled maneuvers to guide itself on a precise flight path back to Earth or the Moon.
The cold gas thrusters use pressurized gas to generate thrust to flip the rocket’s orientation after it is separated from the rest of the rocket.
Later, the grid fins are aerodynamic control surfaces used for precise control of the rocket’s position and orientation before landing and are primarily responsible for the rocket’s incredible landing accuracy.
Once the first stage enters Earth’s atmosphere, the engine is reignited to slow down the rocket and help guide it to the landing destination.
The Second Stage: The Orbital Navigator
Eight seconds after the first stage separates from the rest of the rocket, the second stage’s single Merlin Vacuum engine ignites and begins a seven-minute burn that brings the payload into low earth orbit.
The Merlin Vacuum (MVac) engine burns the same RP-1 and LOX combination but with an extended nozzle optimized for the vacuum environment of space.
After the second stage engine cuts off, and it detaches from the Dragon capsule.
SpaceX has yet to figure out an efficient way to recover the second-stage engine, as the payload penalty is too high compared to the value of reusing the second stage.
However, SpaceX is testing better ways to recover the second stage safely, and there is optimism that it can be done soon.
The Dragon Capsule: The Goods
After detaching from the second stage, the dragon chases the space station via the lower orbit. Once it gets close enough to the International Space Station (ISS), the dragon will establish communication with the ISS through its COTS ultra-high frequency communication unit.
The dragon will open its nose cap before docking at the ISS. The dragon will stay docked at the space station for the next four weeks while the crew unloads the dragon’s payload and reloads it with cargo to be transported back to Earth.
Approximately five hours after the dragon leaves the space station, it will conduct a series of deorbit burns and re-enter Earth’s atmosphere before landing in the Pacific Ocean.
Using a tracker, SpaceX will send a team to locate and recover the capsule before it is prepared to be used again.
The Impact of the Falcon 9
Before the Falcon 9, traditional rockets were single-use, meaning they were discarded after every launch.
By recovering and reusing the first stage and the Dragon capsule, SpaceX significantly reduces the cost of space missions, allowing them to complete a record-breaking number of missions each year.
With SpaceX’s hunger for innovation, I expect the Falcon 9’s second stage to soon be recoverable, further lessening the cost of each spaceflight. Pretty soon, the only non-reusable part of the rocket will be the fuel.
The Falcon 9’s impact on rocketry is undeniable, and I look forward to SpaceX’s further advancements in space travel.
Hello, fellow aerospace enthusiasts! I’m Matthew, a high school student at Portola High School and the creator of The Aero Blog. My journey with aerospace started as a childhood fascination and has grown into a full-blown passion that I am thrilled to share with you through this blog.