This is how STARSHIP kicks off 33 RAPTOR Engines!

The recent Starship Integrated Flight Test, or IFT2, showcased a remarkable achievement by SpaceX. 33 Raptor engines operating simultaneously. This was an unprecedented event in rocket history, and it sets a high bar for any future competitors. It's unlikely that any other rocket will surpass this record in the near future or even in the next few years. One factor that distinguishes modern rockets from their predecessors is the number and size of their engines. While older rockets tended to have fewer but larger engines, newer rockets like SpaceX's Starship have many smaller and simpler ones. Musk recently explained one of the reasons for this choice in a tweet. These two approaches have different benefits and drawbacks. How did SpaceX decide to use multiple engines for their rockets? We'll explore this question in today's episode of Great SpaceX. As mentioned, older generation rockets, mainly in the past century, often used large engines in small numbers. We can clearly see this in one of the world's most famous rockets, the Saturn V. This legendary rocket is powered by the F-1 engine, the king of engines. Compared to most current engines, the F-1 is quite large in size. With a height of 5.8 meters, a diameter of 3.7, and a mass of up to 9 tons, this engine has a huge thrust of 1,522,000 pounds or 690 tons. Each Saturn V rocket uses five F-1 engines. But in this era, when new generation rockets are created, their engines often apply these simplification trend. New generation engines are often smaller, lighter, and less complex than older engines like the F-1. Along with the reduction in size and simplification of design, the number of engines used increased significantly. Let's examine SpaceX's rocket development. After launching the Falcon 1, which had a single Merlin engine, they quickly upgraded to the Falcon 9, which had nine Merlin engines, hence the name. The latest model of the Merlin engine family, the Merlin 1DC level, weighs only 470 kilograms and measures 1.013 meters in height and 0.92 meters in diameter. It produces a thrust of 190,000 pounds or 86 tons. These are much smaller than the F-1 engine's dimensions and power. Similarly, when SpaceX designed Starship, they also introduced a new engine called the Raptor. It follows the same trend of simplification as most other modern engines. The current Raptor 2 version has a height of 3.1 meters, a diameter of 1.3, and a mass of 1.6 tons. It generates a thrust of 230 tons or 510,000 pounds. These are also significantly lower than the F-1's specifications. The future Raptor 3 version will weigh only 1.4 tons and produce 269 tons or 590,000 pounds of thrust. It still cannot match the size and thrust of the F-1. However, the current Starship booster uses up to 33 engines. This number surpasses the number of engines used by the Saturn V. But then again, using many engines has its disadvantages. A large number of engines means that more machines and processes will be needed to control, leading to an increased risk rate. This was made clear as day during the first orbital test flight as well as after the separation phase of the second orbital test flight. Engine ignition is a critical process that requires careful management. It affects vehicles of all types, regardless of the number of engines they have. However, the more engines a vehicle has, the more complex and challenging the ignition process becomes. One common misconception is that all engines on the rocket fire at the same time. In reality, there is often a slight delay of milliseconds between different engines. This may seem negligible, but it can have serious consequences. If the engines that are supposed to provide symmetrical thrust on opposite sides of the do not fire at the same time, the rocket can become unstable and deviate from its planned trajectory. This poses a great risk to the safety of people and infrastructure nearby. This issue is especially relevant for Starship, SpaceX's ambitious rocket project. Its booster stage has, again, 33 engines arranged in three concentric rings. 20 outer engines, 10 middle, and 3 inner. However, this means that it takes about 2 seconds to fire up all the engines. Therefore, the precision and balance of the ignition process are crucial for the stability of the vehicle. Moreover, since the Raptor engine is one of the most powerful engines ever built, and Starship is the largest rocket in the world with thousands of tons of explosive fuel inside, any error could result in a catastrophic failure. Besides, this process also depends on the reliability of the engine itself, which was a challenge that SpaceX faced during its first orbital test flight. So, with all of these disadvantages, why did SpaceX decide to go with a lot of engines instead of one big one? Well, one of the advantages of having multiple engines is to increase flight stability. Rockets with more engines can distribute the thrust ratio better than rockets with fewer. This was recently explained by Musk in his tweet, Starship has 33 engines. If an engine failure is isolated, then many engines greatly increases reliability. Starship only loses around 3% of thrust. If not, then reliability is terrible. The difference is at least 2 orders of magnitude. For instance, if 2 or 3 Raptor engines malfunction, the flight might still continue normally or with minimal impact. But if 2 or 3 large engines like the F-1 stop working, the flight will definitely be severely affected or even fail immediately. Another benefit of using multiple engines is that it makes it easier for SpaceX to upgrade the vehicle's power. You see, adding more engines will be much simpler than developing a whole new version with higher power. For example, to create the Falcon Heavy, SpaceX just added 2 side boosters to the Falcon 9, creating a first stage with 27 engines. Or with Starship, instead of waiting for the research process to create powerful engine versions like the F-1, they just need to increase the number of engines. With 33 Raptor engines, Starship can also surpass the Saturn V to become the most powerful rocket in the world, although one Raptor engine has less thrust than one F-1. As for the difficulty related to the ignition process, perhaps it won't stop SpaceX's genius engineers and technological advances. Compared to the last century, the current technology has developed much more. Modern computers and controllers have been applied to make engine control easier and more efficient down to the millisecond, and they continue to improve. We can see that at SpaceX. Their first flight had quite a few engines fail after takeoff, but after only 7 months, they have improved the engine system very well. Ignition was smooth, the 33 engines remained efficient, and no failure occurred during the first 2 minutes of flight. Based on that success, SpaceX will continue to make future improvements. First, they will help the engines operate more stably during the flight. Once they are reliable enough, the number of engines will probably be increased. 33 engines will certainly not be the final limit. We can look back to the past when SpaceX designed the first version of Starship, the Interplanetary Transport System it was called at the time. The number of engines in the first stage was up to 42. SpaceX had also planned to create a larger version of Starship, like Starship version 2.0. If that comes true, the number of engines will probably be increased accordingly. It can then be said that there is no limit that SpaceX cannot reach, including changes in the number or design of the engines. It's just a matter of whether they want to do it and whether it benefits their rocket or not. There will be a lot more things that SpaceX needs to do in the future, but they can be confident that they are doing well with Starship in general and the Raptor engine in particular. The strides with the engine in the recent flights is the most obvious example. This just goes to prove that SpaceX made the right choice. In the meantime, we'll just wait for SpaceX to continue creating new innovations. Hopefully in the future, it won't be just 33 engines, but perhaps many more engines lighting up together during Starship's flight. That will power SpaceX to help the US aerospace industry as well as humanity go further in space exploration. Well folks, that's about it for today's episode. Thank you so much for tuning in and if you'd like to support our channel even further, you can go ahead and hop on over to our Patreon through the link in the description below. Sign up today and become a patron to gain access to exclusive content. Sounds exciting, right? In any case, we still appreciate your generosity and your passion for space exploration. As always, this is Kevin from Great SpaceX and until next time, keep looking up!