In the 21st century, a new space race is unfolding – this time with the United States and a united, motivated Europe at the start. While the United States and Europe are partners in many space projects, they are also competing for technological leadership. Who will take the lead in space exploration – America or Europe? The modern space industry is changing rapidly: private companies, new rockets, and engines are emerging. Let’s take a look at the capabilities of both players, their key programs, and the “battle of the engines” between the already basic American Raptor and the innovative European ARCOS. This will allow us to see whether Europe can close the gap and catch up with the United States in space exploration.
United States capabilities and ambitions
Today, the United States is confidently setting the pace in the space industry. NASA is implementing the ambitious Artemis program to return humans to the Moon and create the Gateway lunar orbital station. The first stages of Artemis are already being implemented: at the end of 2022, NASA successfully launched the SLS super-heavy rocket with the Orion spacecraft on an unmanned flyby of the Moon, and in the coming years, astronauts are planned to land on the lunar surface. Next in line is the goal of sending humans to Mars in the 2030s. These United States government programs are backed by significant funding (NASA’s budget is several times larger than ESA’s) and active cooperation with the private sector.
Private space companies in the United States have become a separate engine of progress. First and foremost, it is SpaceX, a company that has made a breakthrough in reusable rocket launches. Its Falcon 9 rockets have learned how to return the first stage and reuse it: individual boosters have already completed about 20 work cycles, which has significantly reduced the cost of delivering cargo to orbit. SpaceX is making a record number of launches per year, and its reusable Dragon cargo ship regularly carries NASA astronauts to the ISS. In addition to SpaceX, there are other giants in the United States: Blue Origin is preparing the New Glenn heavy rocket for flight, ULA is developing a new Vulcan launch vehicle, and startups like Rocket Lab are successfully launching small rockets. Taken together, public and private initiatives have given the United States a significant advantage: America is the first to test super-heavy reusable systems, such as SpaceX’s colossal two-stage Starship complex, capable of placing more than 100 tons into orbit. It is Starship that is planned to be used as a lunar lander for the Artemis program and in the future for flights to Mars. Thus, the United States has both experience and technology: from the longest history of manned spaceflight (the Apollo program) to the most innovative developments of today.
Europe’s opportunities: from Ariane to new horizons
Europe is represented in the space arena collectively through the European Space Agency (ESA) and national agencies of EU countries. By combining the resources of many countries, Europe has created its own family of launch vehicles, Ariane and Vega, and is also conducting extensive scientific programs. European space achievements are impressive: from successful commercial satellite launches by Ariane 5 rockets (which have been the workhorse of the global launch market for more than 15 years) to famous scientific missions (Rosetta to a comet, Mars Express in Mars orbit, Herschel telescope, etc) ESA is a key partner of NASA in its projects: it is Europe that manufactures the Orion spacecraft’s Service Module for the Artemis missions, supplies modules for the Gateway station, and has its own Columbus module in the ISS. At the same time, Europe also has obvious limitations: it still does not have its manned spacecraft or the ability to launch people (European astronauts fly on American ships), and its budgets and development rates are inferior to those of the United States.
The European rocket and space technology is currently focused on developing the next generation of launch vehicles. In 2024, the Ariane 5 will be replaced by the new Ariane 6, a modular medium-heavy launch vehicle from the ArianeGroup joint venture. It is designed to provide Europe with independent access to space for decades to come, launching Galileo navigation satellites, scientific vehicles, and commercial cargo. Ariane 6 has become more cost-effective than its predecessor, but, unlike the American Falcon 9, it remains disposable (after launch, its stages burn up or fall into the ocean). European engineers are actively working on reusable technologies: the Prometheus methane engine (similar in purpose to SpaceX’s Merlin and Raptor) and the experimental reusable Themis stage are being developed to form the basis for the future Ariane Next rocket in the 2030s. At the same time, new players are emerging: many European startups have rushed into the space business. For example, the German companies Isar Aerospace and Rocket Factory Augsburg are developing small orbital launch vehicles, and the Spanish PLD Space successfully launched the Miura-1 micro rocket in 2023.
Europe pays special attention to the development of innovative engines. Traditionally, European rockets have been equipped with reliable but conservative liquid hydrogen engines (for example, Vulcain and Vinci for Ariane). Now, European engineers are seeking to master methane fuel and new designs. Pangea Aerospace, a Barcelona-based company specializing in rocket engines and working closely with ESA, has become the flagship here. It has undertaken to create something that has remained only a theory for decades – an aerospike engine for a rocket. This promising engine is called ARCOS and is seen as a chance for Europe to make a technological leap.
Raptor vs ARCOS: a battle of rocket engines
One of the key success factors in today’s space race is advanced rocket engines. Currently, the spotlight is on two state-of-the-art engines: the American Raptor and the European ARCOS, which may determine the advantage of one side or the other in the coming years. Both use environmentally friendly methane fuel (methane + liquid oxygen), but represent different approaches to rocket engine engineering. Let’s look at their features and compare them by key parameters.
Image: SpaceX
Raptor is a SpaceX development, one of the most advanced engines in the world. It was created for the Starship rocket and has already set several records. The Raptor operates on a Full-Flow Staged Combustion (FFC) scheme, a highly complex but very efficient combustion cycle where both fuel and oxidizer pass completely through high-pressure turbines. SpaceX is the first company to implement this principle in a flight engine. As a result, the Raptor achieves extremely high performance: its thrust exceeds 2 MN (~200 tons-force), and its specific impulse (fuel efficiency) is about 327 s at sea level and up to ~380 s in vacuum. For comparison, previous generations of engines (e.g., Merlin on Falcon 9) have a momentum of ~282 s at sea level. The Raptor operates at a record combustion chamber pressure of ~300 bar, which places great demands on the materials and design of the turbopump. SpaceX is actively improving this engine: the Raptor 2 version has become easier to manufacture and lighter, raising the thrust ratio to ~150:1, and the latest Raptor 3 version has further increased this figure (thrust ratio ~184:1) and reached a thrust of ~280 tons. Raptor is designed to be reusable – each engine is theoretically designed for dozens (or even hundreds) of launches with minimal maintenance. Despite its high complexity and cost, SpaceX is seeking to reduce the cost of the Raptor through mass production. According to Elon Musk, the goal is to make the engines so cheap and reliable that the Starship can make regular “aerospace flights” like an airliner.
The European ARCOS engine has a fundamentally different nozzle design. It is a wedge-air engine. Instead of the usual bell-shaped nozzle, which restricts the gas flow by the walls, a conical “wedge” (in the center) is used, around which the jet expands. The advantage of this scheme is automatic adaptation to external pressure. In other words, the aerospike nozzle works effectively at different altitudes: at sea level, it “presses” the jet, preventing the gases from expanding more than necessary, and in a vacuum, the jet expands freely without loss. Thanks to this, the aero-spike maintains close to optimal thrust throughout the flight, while conventional engines have only one point of optimal operation (at a certain altitude). The difference is tangible: it is believed that an aerospike engine can provide 10-15% more efficiency compared to a traditional nozzle, and for large rockets, the increase can theoretically reach ~20%. This is not a new idea – NASA designed an experimental aerospike engine for the X-33 shuttle back in the 1990s, but then material technology did not allow it to be completed. Pangea Aerospace was able to bring the concept to reality thanks to 3D metal printing and new heat-resistant alloys. In 2021, Germany conducted the first successful fire tests of the DemoP1 prototype on methane and oxygen, which developed a thrust of 20 kN. The next version, ARCOS, is being developed to be much more powerful, with a target thrust of ~750 kN (about 75 tons), which is suitable for upper stages of medium and heavy class rockets. Pangea plans that ARCOS will be able to work in conjunction with a reusable stage: due to its efficiency and compactness, this engine should allow the upper stages of a rocket to be returned and reused, which no one except SpaceX has even tried to do so far. The project is supported by Europe – in early 2025, a consortium led by Pangea received a €7.27 million grant to bring ARCOS to flight status. The first tests of the full-size module took place in 2023, and if the development goes according to plan, Europe will receive the world’s first working aerospray rocket engine.
So, Raptor and ARCOS are both leading methane engines, but they embody different approaches. Let’s summarize their comparison by the main aspects.
Energy efficiency: Both engines exhibit high specific impulse. Raptor achieves very high efficiency (over 350 s in vacuum) due to its perfect combustion cycle. ARCOS is theoretically capable of increasing efficiency by 10-15% in critical launch modes when conventional engines lose thrust due to excessive gas expansion. This means that a rocket with an aerospike engine can launch a larger payload with the same fuel mass or save fuel for maneuvers.
The complexity of the design: The Raptor is an extremely complex engine. A full cycle with two boosters requires a complex system of pipelines, turbo pumps, and valves that operate under extreme pressures. SpaceX has managed to tame this technology, but at the cost of many years of testing and significant investment. ARCOS, on the other hand, is simple to cycle (probably using a simpler fuel supply scheme such as a generator or step cycle), but it is the aerospike nozzle that is a technological challenge. The large surface area of the “wedge” requires efficient cooling, as it is subject to a gigantic heat flux. Pangea solves this problem by using dual-circuit cooling: methane and oxygen flow through the nozzle’s two-layer walls, removing heat. Without modern 3D printing, it would be impossible to realize such complex channels. So, Raptor is complex in its internal components, and ARCOS is complex in its shape and materials, but both projects have shown the viability of the solutions chosen.
Cost of production: SpaceX aims to radically reduce the price of the Raptor through mass production and standardization. Already, Raptor is being printed on 3D printers and assembled on an assembly line, which is unusual for rocket engines. The ultimate goal is to produce a large number of relatively inexpensive, reusable engines. However, the Raptor is still expensive at present: high-precision components and heat-resistant materials are costly, and Musk has acknowledged that further design simplifications are needed to make the Starship economically viable. ARCOS, as a startup development, has been focused on additive manufacturing and lower-cost materials from the start. Pangea Aerospace boasts that new alloys and 3D printing have made the impossible possible – to produce an aerospike that was once considered too expensive and difficult to practice. With the support of ESA and the Spanish government, Pangea is working to bring the technology to mass production. If it is possible to produce ARCOS for European rockets, the fuel savings and potential reusability could offset the cost of its development.
Application prospects: The Raptor engine is already driving astronautics forward today – it is the basis for the Starship system, which is capable of making a breakthrough in the colonization of the Moon and Mars. If successful, Starship with Raptor will change the rules of the game: launches will be an order of magnitude cheaper, and the volume of cargo will be an order of magnitude larger. The European ARCOS has not yet flown in space, but it is a strategic chance for Europe to reduce its technological gap. If aerospike engines prove themselves in practice, European rockets of the next generation will be able to do without complex multi-stage schemes (because one aerospike engine works effectively both at launch and in vacuum) or will gain in payload. In addition, ARCOS can make a reusable upper stage a reality – something SpaceX is currently working on for Starship. In other words, Europe will find its niche of innovation, not just catch up with American solutions.
ARCOS – Europe’s chance to catch up with the US
The development of the ARCOS engine is a good example of the European strategy: to rely on innovations that can become a trump card in competition. While the United States already has an advantage in reusable rockets, Europe is striving to leap ahead with unique technologies. The wedge-air engine is exactly the kind of technology that can give European launchers a competitive advantage. If Pangea Aerospace successfully brings ARCOS to operation in the coming years, Europe will be able to create a rocket with efficiency close to that of American developments, and perhaps even surpass them in some aspects. Of course, a new engine alone will not solve all the problems: a lot of investment, testing, and political will are needed to implement these solutions in production missiles. However, ARCOS has already united European engineers and shown that Europe is ready to take risks for a technological breakthrough.
Will Europe catch up with America?
Thus, the United States is still leading the modern space race thanks to a combination of generous funding, government programs (Artemis), and the unprecedented role of private companies. Europe, with fewer resources and a more bureaucratic structure, lags in terms of speed of development and scale of projects. However, the European approach is a marathon, not a sprint: a gradual build-up of capabilities through cooperation and precision engineering solutions. The Ariane program has given Europe reliable rockets, and new initiatives like ARCOS can provide a leap in efficiency. Europe is also actively cooperating with the United States (joint missions, technology exchange), so both sides benefit.
Can Europe catch up with America?
It can be said that Europe is already claiming certain “niches” of leadership, for example, in scientific research missions or satellite technologies. In the field of launches and rocket engines, the gap is still significant, but not critical. If European countries continue to invest in innovations (such as reusable systems and wedge engines) and support their engineers and startups, the gap will gradually close. In the next decade, a new European rocket with an aero-fusion engine may be launched and compete with the American ones. At the same time, given SpaceX’s current pace, it will not be easy to catch up with the United States – we will have to run as fast as we can. Space is big, and there is a place under the Sun for everyone, but the race for the championship continues. America is in the lead, but Europe is determined to stay the course and has a few tricks up its sleeve.
