What does the “most powerful rocket in the world” even mean?
On November 16, 2022 NASA launched the Space Launch System or SLS. This was a rocket that produced 8.8 million pounds of thrust using a combination of two solid rocket boosters and 4 liquid fueled engines. The Saturn V rocket produced 7.5 millions pounds of thrust from its five F1 engines. The Space Shuttle produced 7.8 million pounds of thrust with two solid rocket boosters and 3 liquid fueled SSME engines. The Soviet N1 rocket which never achieved operational success used 30 NK-15 engines to produce 10.2 million pounds of thrust. Enter Elon Musk.
Building on the success of the Falcon9 Merlin rocket engine, SpaceX was determined to build an even more monstrous rocket that would be capable of interplanetary flight. Initial testing of a Raptor rocket engine began around 2016. These tests were crucial in validating the engine’s design and performance characteristics under various conditions. SpaceX conducted the first test of a Raptor engine on a Starship prototype in July 2019. This test involved a prototype known as “Starhopper,” which was fitted with a single Raptor engine. Starhopper was a test vehicle designed to demonstrate low-altitude and low-velocity flight capabilities, crucial for the development of the Starship spacecraft. The Raptor engine is a full-flow staged combustion engine and uses liquid methane (CH₄) and liquid oxygen (O₂) as its propellants, a change from the RP-1 kerosene used on the Falcon9 rockets.
Methane
SpaceX’s decision to use liquid methane (CH₄) as the fuel for its Raptor engines, instead of traditional rocket fuels like kerosene or liquid hydrogen, is based on several strategic and technical considerations. Liquid methane offers a balance between performance and handling. It has a higher efficiency compared to kerosene, though slightly lower than hydrogen. This makes it more efficient for space travel, particularly for missions beyond Earth orbit. Methane is denser than hydrogen, leading to smaller and lighter fuel tanks. This is beneficial for the overall mass and structure of the rocket, especially for large-scale vehicles like the Starship and Super Heavy. Liquid methane is stored at cryogenic temperatures, but not as low as liquid hydrogen, making it easier to handle and store.
Methane eases the requirements for insulation and reduces boil-off, which is a significant issue with hydrogen. Methane can be easily liquefied and reliquefied, an essential feature for SpaceX’s vision of rapid reusability. This property is critical for the turnaround time of their rockets. Unlike kerosene, methane can be synthesized from Martian resources (using the Sabatier reaction, which combines carbon dioxide and hydrogen to produce methane and water).
Methane engines align with SpaceX’s long-term goal of Mars colonization, as it allows for the possibility of in-situ resource utilization (ISRU) – producing fuel directly on Mars for return journeys or other exploration missions. Methane burns cleaner than kerosene, producing less soot. This is beneficial for engine lifespan and reliability, crucial factors for reusable engines like the Raptor. Liquid methane is chosen for its efficient balance of performance, handling, and reusability, along with its potential role in future Mars missions, making it a strategic choice for SpaceX’s ambitions in space exploration.
As the manufacturer, SpaceX oversees the entire production process of the Raptor engines, ensuring they meet the specific requirements for their ambitious space exploration goals. SpaceX announced the production of Raptor 2 engines in December 2021, emphasizing their simplified yet more powerful design compared to the original Raptor. The engines are manufactured at SpaceX’s engine development facility near McGregor, Texas.
The Raptor
Engine Specifications and Evolution:
- Raptor 1: The initial version of the Raptor engine produced a thrust of 185 tons-force (1.81 MN; 408,000 lbf).
- Raptor 2: This version represented a complete redesign of the Raptor 1 engine, with changes in the turbomachinery, chamber, nozzle, and electronics. The Raptor 2 engines achieved a consistent thrust of 230 tons-force (2.26 MN; 507,000 lbf) at sea level and 258 tons-force (2.53 MN; 569,000 lbf) in a vacuum. SpaceX expected to be able to tune these engines over time to achieve at least 250 tons-force (550,000 lbf).
- Raptor 3: The latest iteration, Raptor 3, generates 269 tons-force (2.64 MN; 593,000 lbf) of thrust.
Raptor engines will enable the Super Heavy booster to carry out demanding missions such as deep-space exploration and potential future Mars colonization missions.
On April 20, 20023 IFT-1 of Starship 7 and Super Heavy Booster 24 demonstrated the world largest and most powerful rocket ship could fly. The boosters 33 Raptor 2 engines produced 16.7 million pounds of thrust. Later that same year, IFT-2 occurred on November 18th and successfully completed stage separation. These flight tests proved the performance and reliability of the Raptor engine. These engines are a marvel of engineering and ingenuity. Getting all the components, values, pumps seals and software to work harmoniously and perfect for one engine a triumphed feat. Doing it for 33 new and un-flight proven engines is tantamount to a miracle.
The article “Feeding the Beast: Super Heavy’s Propellant Distribution System” offers an in-depth analysis of SpaceX’s Super Heavy rocket’s complex propellant distribution system. The Super Heavy, boasting 33 Raptor engines, utilizes cryogenic Liquid Methane and Liquid Oxygen as fuel and oxidizer, stored in large main tanks. A key feature is the Liquid Oxygen “landing” tank, which aids in reducing propellant sloshing effects during landing burns. The article meticulously breaks down the system, starting from the aft bulkhead of the Liquid Oxygen Tank, highlighting the intricate network of feed holes and pipes that distribute propellants to the engines.
Detailed attention is given to the Liquid Methane Distribution Manifold, its connection to the engines, and the Liquid Methane downcomer base, a crucial part of the system. The article also explores the Liquid Oxygen Landing Tank, integral for the ring of 10 engines, and the Liquid Methane Sump, detailing how these components interact within the larger system. Additionally, it discusses the main propellant valves, essential for controlling the flow of propellants to the engines.
The article concludes by underscoring the effectiveness of this design in supporting a full-duration first-stage ascent, showcasing the capability of the system to supply all engines with necessary propellants. The intricate details provided in the article, complemented by real photos and renders, offer a comprehensive understanding of Super Heavy’s propellant distribution system. Check it out at this site: Feeding The Beast: Super Heavy’s Propellant Distribution System (ringwatchers.com)https://ringwatchers.com/article/booster-prop-distribution
