Spacecraft propulsion is any device which is used to propel spacecraft and artificial satellites. Satellite propulsion or in-space propulsion exclusively deals with propulsion systems used in the vacuum of space. Space propulsion is a method used to accelerate spacecraft or artificial satellites. The function of the propulsion system is to produce thrust, which is the force that moves a rocket through air and space. Different propulsion systems generate thrust in different ways, but always through some application of Newton’s third law of motion. In any propulsion system, a working fluid is accelerated and the reaction to this acceleration produces a force on the system. A general derivation of the thrust equation shows that the amount of thrust generated depends on the mass flow through the engine and the exit velocity of the gas.
Currently space propulsion systems include two main solutions. Electric Propulsion (EP) uses electric power (provided by solar panels or a nuclear source) to accelerate ionised propellant. And Chemical Propulsion (CP) uses the propellant itself as source of energy for the propulsion. The shift from traditional propulsions (chemical propulsion system) in spacecraft to the new generation propulsions systems (electric propulsion system) is expected to open new market opportunities in the coming years.
The global space propulsion market is projected to grow from USD 6.7 billion in 2020 to USD 14.2 billion by 2025, at a CAGR of 16.2% from 2020 to 2025. The space propulsion market faced a slight decline from 2018 to 2019 due to a decrease in the number of space launches. COVID-19 has also affected the import and export trading activities in the space industry. The rapid spread of COVID-19 in Europe, the US & Asia Pacific has led to a significant drop in demand for space propulsion system globally, with a corresponding reduction in revenues for various suppliers and service providers across all markets owing to late delivery, manufacturing shutdown, the limited staff at manufacturing facilities, and limited availability of equipment.
However, the expected rise in space launches from 2021 and beyond will drive the space propulsion market. As per industry experts, the global space propulsion demand is anticipated to recover by 2022.
The market is driven by various factors, such as an increase in the number of space exploration missions, demand for LEO-based services, and increasing demand for advanced electric propulsion systems. The market is driven by Government and private sector projects, Demand for low-cost small satellites and reusable space launch vehicle production.
Space program development has been on the rise during the past decade in an increasing number of countries, aiming to acquire independent assets to help their national, social, economic and technological development and contribute to their national defense and security programs. Space access budgets continued to increase over the past 5 years at a 10% Compound Annual Growth Rate (CAGR).
In the coming years, there will be an increase in public and private initiatives in space exploration with a converging global interest in moon exploration. Global government investments in space exploration totaled USD 14.6 billion in 2017, a 6% increase from 2016. Moon and Mars explorations are expected to account for most of the space missions to be launched by 2027, with lunar exploration becoming the focus of private and public stakeholders. A total of 18 missions are anticipated to be launched for other deep space exploration, while the remaining missions will be dedicated to Mars exploration.
Currently, the major difficulties of operating unmanned space missions are related to energy and propellant required for launch, transfer orbit, and maneuvering the satellite or spacecraft in orbit. Ongoing studies indicate that the area of greatest challenge has been identified to be propulsion. Undertaking such missions requires developing new space propulsion rocket engine systems. Space launch vehicles must be capable of reaching transfer orbits and detach from their spacecrafts, which, driven by new propulsion systems with high energy levels, will continue until the final destination. The main engines require improvement if reliability and cost goals are ever to be met.
In the last fifteen years, the business of space exploration changed substantially, with space startups and private corporations joining governments in creating and launching satellites and other spacecraft with the launch vehicles. Thus, the demand for space propulsion systems has increased.
The advent of low-cost satellites and development of reusable space launch vehicles are some of the major factors driving the growth of the market. The usage of new-generation and reusable launch vehicles are paving the way for another successful and cost-effective makeover of the domain of satellite systems. In recent years, a number of countries are focused on innovative, profitable satellite launches.
Also, satellite launches are mostly done using expendable launch vehicles (ELV) that carry a payload to the orbit and can be used only once. The majority of the satellite launch cost comes from building the rocket, which gets used for a single mission. However, instead of an ELV, a reusable space launch vehicle can substantially reduce the cost of access to space, if the rockets could be effectively used for multiple missions, similar to that of airplanes. Companies such as SpaceX have been working to develop such reusable space launch vehicles that can re-enter the earth without burning and return to the launchpad for a vertical landing.
Also, the rapid deployment of CubeSats is one of the newest trends in the market. With the growing demand for nano and microsatellite, it is expected that the manufacturing base of satellites will widen to various regions of the world. Many of the developing nations have also shown a keen interest in the utilization of satellites such as CubeSats (U-class spacecraft). These satellites use enhanced electro-optical/infrared (EO/IR) sensor systems to obtain images of Earth. Earth Observation (EO) from such nanosatellite platforms will revolutionize the scope of the EO/IR sensors. These satellites are majorly accelerated using all-electric propulsion systems, which widens their mission capabilities, reduce their weight, and lessen their launch costs.
Geographical insights
The Satellite Propulsion Systems market in the U.S. is estimated at US$5.7 Billion in the year 2020. China, the world’s second largest economy, is forecast to reach a projected market size of US$4.5 Billion by the year 2027 trailing a CAGR of 3.6% over the analysis period 2020 to 2027. Among the other noteworthy geographic markets are Japan and Canada, each forecast to grow at 3.6% and 3.1% respectively over the 2020-2027 period. Within Europe, Germany is forecast to grow at approximately 3.7% CAGR.
In the global All-Electric Propulsion segment, USA, Canada, Japan, China and Europe will drive the 3.2% CAGR estimated for this segment. These regional markets accounting for a combined market size of US$2.5 Billion in the year 2020 will reach a projected size of US$3.1 Billion by the close of the analysis period. China will remain among the fastest growing in this cluster of regional markets. Led by countries such as Australia, India, and South Korea, the market in Asia-Pacific is forecast to reach US$2.8 Billion by the year 2027.
Government & defense segment is estimated to account for the largest market share in the year 2020
The presence of prominent space organizations such as the National Aeronautics and Space Administration (NASA) is driving the market growth in the region. Furthermore, the presence of leading satellite propulsion system providers such as Boeing, and Aerojet Rocketdyne is also boosting the market growth in the region.
European Space Agency (ESA) announced a nearly USD 33 million investment in Hall Effect Thruster (HET) propulsion technology and other business incubators. China also dedicated USD 339 billion for start-ups in the country , which is a sign that governments compensate for the lack of private funding. The Canadian government’s Industrial Technologies office plans to provide Canada-based UrtheCast with USD 13 million to support the ongoing development of its X- and L-band synthetic aperture radar (SAR) constellation on a smallsat platform. Thus, increased government investments will offer growth opportunities for the space propulsion market. Recently, Japan initiated a cabinet-level ImPACT (Impulsing Paradigm Change through Disruptive Technologies) program, which can potentially advance space start-ups.
The government & defense segment is estimated to have the largest revenue market share in 2020. The growth of this segment can be attributed to increasing space exploration missions and rising space budgets. Defense organizations support the use of various types of satellites, such as remote sensing satellites, communication satellites, and surveillance satellites, for military operations and cyber operations. Support operations usually involve the launch of satellites with high-value payloads in space through Expendable Launch Vehicles (ELVs). They also ensure monitoring by facilitating the friendly use of space for various operations, such as surveillance, protection, and space intelligence analysis. For instance, the US Air Force regularly launches GPS and missile-defense tracking satellites and operates two classified X-37B robotic space planes.
Satellites: The fastest-growing segment of the space propulsion market, by platform
Based on Platform, the Space Propulsion Market studied across Capsule/Cargo, Interplanetary Spacecraft and Probes, Launch Vehicles, and Satellite. Based on Orbit, the Space Propulsion Market studied across Beyond Geosynchronous Orbit, Geosynchronous Orbit, Low Earth Orbit, and Medium Earth Orbit.
By platform, the satellite segment is estimated to be the largest and fastest-growing segment in the space propulsion market. Amid the COVID-19 crisis, the global market for Satellite Propulsion Systems estimated at US$19.4 Billion in the year 2020, is projected to reach a revised size of US$25.1 Billion by 2027, growing at a CAGR of 3.8% over the analysis period 2020-2027.
The growth of this segment can be attributed to rising small satellite launches for commercial and government applications. Large satellites, medium satellites, CubeSats, and small satellites, including nanosatellites, microsatellites, and minisatellites, play an important role in Earth observation, communication, and meteorology applications. These satellites are capable of monitoring cyclones, storms, El Nino, floods, fires, volcanic activities, earthquakes, landslides, oil slicks, environmental pollution, and industrial and power plant disasters
Chemical Propulsion, is projected to record a 4.2% CAGR and reach US$15.5 Billion by the end of the analysis period. After an early analysis of the business implications of the pandemic and its induced economic crisis, growth in the Hybrid Propulsion segment is readjusted to a revised 3.3% CAGR for the next 7-year period.
The non-chemical propulsion segment is projected to witness a higher CAGR during the forecast period
Space propulsion technologies can be framed in three different categories: “escape propulsion” (from Earth surface to orbit), “in-space propulsion” (in orbit), and “deep space propulsion” (from orbit to outer space). The launch vehicles currently used for “escape propulsion” rely on very mature technologies, but for “in-space” and “deep space” vehicles, there are prospects of significant technological advances. Recently, Johnson (2012) noted that “in-space” propulsion begins where the launch vehicle upper stage leaves off and starts performing the functions of primary propulsion, reaction control, station keeping, precision pointing, and orbital maneuvering.
Space propulsion types
Based on propulsion type, Space Propulsion can be classified into Chemical Propulsion and Non-Chemical Propulsion. The Chemical Propulsion further can be Green, Hybrid, Liquid, and Solid. The Non-Chemical Propulsion includes Hydrogen, Electric Propulsion using Argon, Krypton and Xenon., Laser Propulsion, Nuclear Propulsion, Solar Electric Propulsion, Solar Propulsion, Solar Sail Propulsion, Solar Thermal Propulsion, Tether Propulsion. There is no single propulsion technology that will benefit all missions or mission types.
Solid fuel propulsion
In a solid rocket fuel grain, all the components required for vigorous combustion are mixed together and packed into a solid cylinder, as shown in Fig, into one substance. Once the combustion starts, it proceeds until all the propellant is exhausted. There will be an oxidizer (usually a salt such as ammonium perchlorate or potassium nitrate), a fuel (HTPB – Hydroxyl Terminated Polybutadiene) or some other solid hydrocarbon and an accelerant (sulphur, powdered aluminium, or other easily oxidized metal).
Liquid fuel propulsion
Propellant is comprised of two composites: fuel and oxidizer, as shown in Fig.. They are stored separately in tanks in liquid phase and are pumped into the nozzle combustion chamber where burning occurs. Engine can stop the combustion and the thrust by turning off propellant flow. Liquid rockets tend to be heavier and more complex because of the pumps and storage tanks
Hybrid propulsion
As the name implies, “hybrids” are a cross between other types of rocket motor, in particular, liquid fueled rockets and solid fuel rockets. They were conceived to overcome the complexities of liquid bi-propellant engines and the lack of controllability of solid rocket motors
According to Long (2012), chemical fuels are clearly inadequate for interstellar missions and new methods of propelling a vehicle through space should be invented. Based on the propulsion type, the non-chemical segment of the space propulsion market is projected to register a higher CAGR than the chemical segment during the forecast period. The growth of the non-chemical propulsion segment can be attributed to the demand for velocity increments in modern propulsion systems. The non-chemical propulsion system’s efficient use of fuel and electrical power enables modern spacecraft to travel farther, faster, and cheaper than any other propulsion technology currently available. Chemical propulsion systems have demonstrated fuel efficiencies up to 35 percent, but ion thrusters have demonstrated fuel efficiencies over 90%.
The market has been segmented into cold gas propulsion, pulsed plasma thrusters, green liquid propulsion, water electrolyzed, hydrazine, micro electrospray propulsion, iodine hall propulsion, solar sail propulsion, and ambipolar thruster. The ambipolar thruster segment dominated the market in 2018 and is expected to grow at the highest CAGR from 2019 to 2025. An ambipolar thruster is the type of a thruster designed as a propulsion system for CubeSats. The increasing adoption of CubeSats by various countries such as the US, China, India, and others is driving the growth of the segment. The propulsion system of a rocket includes all the parts that make up the rocket engine: tanks, pumps, propellants, power head, and rocket nozzles.
Challenge: Emissions due to space missions
Space launches can produce a hefty carbon footprint due to the burning of solid rocket fuels. Every time a rocket is launched, it produces a plume of exhausts in its wake that leaves a mark on the environment. These exhausts are filled with materials that can collect in the air over time, potentially altering the atmosphere in dangerous ways. Small pieces of soot and a chemical called alumina are created in the wakes of rocket launches. These materials may build up in the stratosphere over time, slowly leading to the depletion of a layer of oxygen known as the ozone. With a significant increase in the number of space missions, the emission scale of harmful gases is also expected to increase.
The global space propulsion system market is gaining widespread importance owing to increasing efforts from commercial space companies as well as space agencies for developing more efficient, less-toxic and enhanced space propulsion systems to contribute to the significant growth of the space propulsion system market. Moreover, the development of cost-efficient propulsion technologies, advancements in the 3D printing technology for developing the components of space propulsion systems are some of the factors that may propel the market growth in the coming years.
Green propellants
According to Gohardani et al. (2014), currently, toxic and carcinogenic hydrazine propellants are commonly used in spacecraft propulsion. These propellants impose distinctive environmental challenges and consequential hazardous conditions. Green Propellants is a general name for a family of propellants, being used in liquid, solid, hybrid, mono or bipropellant engines, which satisfy certain requirements such as low toxicity, low pollution, good storability, wide material compatibility and good performance
IN-Space Propulsion
The beginning of the space region that can be characterized as “in-space” propulsion is the point where the launch vehicle upper stage leaves off, and starts performing the functions of primary propulsion, reaction control, station keeping, precision pointing, and orbital maneuvering (Johnson 2012). The main engines used “in-space” provide the primary propulsive force for orbit transfer, interplanetary trajectories and planetary landing and ascent. Action control and orbital maneuvering systems provide the propulsive force needed for maintaining orbit, position control, station keeping, and spacecraft attitude control.
New “in-space” propulsion technologies development will result in improvements in thrust levels, power, specific mass (or specific power), volume, system mass, system complexity, operational complexity, commonality with other spacecraft systems, manufacturability, durability, and, of course, cost. “In-space”, defined as the region between Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO), includes all Earth monitoring systems, such as communications strategic assets, early warning, Earth observation, navigation, reconnaissance, surveillance and weather.
Electric Propulsion (EP)
Recent developments in the field of EP have brought this technology to the forefront of the space scene. Today, EP systems offer new business models and a real economic paradigm shift in the telecommunication-by-satellite sector. This commercial sector represents almost half of the revenues of the European satellite manufacturing industry revenue and is therefore of the utmost importance.
Today EP is also considered as a revolutionary technology that will contribute substantially to the performance of future scientific and operational space missions. EP could potentially allow new missions, by expanding the limits of reachable space. Subsequently EP will impact scientific progress and boost growth in areas such as space telecommunications, navigation, and Earth observation.
EP is an important technology for the EUR 310 billion global space industry, being a EUR 28 billion sector itself. Its importance in Europe relates both to the European space capability and the competitiveness of a strategic industry. Today, the satellite propulsion market is still experiencing a transition phase from CP to EP. And Europe needs to urgently catch up with American and Russian competitors in order to maintain its good position on the global scene.
Developing a competitive EP system requires a considerable investment. For this reason a public support to R&D is crucial. Innovation is at the heart of the competitiveness of this industry. To win the global race, the emergence of disruptive solutions that will provide a substantial competitive advantage to Europe is essential. In this context, it is the SMEs that are the best placed to innovate and conduct early and high-risk research. And active contribution of commercial customers would allow for more market driven developments.
Solar sail propulsion
The solar sail is another concept of propulsion. It is basically a big photon reflector surface. The power source for the solar sail is the Sun and it is external to the vehicle (Sutton, 2000). Solar sail propulsion uses sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. According to Johnson et al. (2011), solar sail propulsion utilizes the solar radiation pressure exerted by the momentum transfer of reflected light. The integrated effect of a large number of photons is required to generate an appreciable momentum transfer; therefore, a large sail area is required. Since acceleration is inversely proportional to mass for a given thrust force, the mass of the sailcraft must be kept to a minimum.
Tether propulsion
The tether propulsion consists of a long, thin wire deployed from an orbiting satellite or vehicle. The movement of a wire through a magnetic field produces an electrical current. The current in the wire produces a magnetic field around the wire, which interacts with the Earth magnetic field. The force exerted on the tether by Earth magnetic field can be used to raise or lower a satellite orbit, depending on the direction of the current.
Laser propulsion
Laser propulsion is a form of beam-powered propulsion where the energy source is a remote (usually ground-based) laser system and separate from the reaction mass. This form of propulsion differs from a conventional chemical rocket where both energy and reaction mass come from the solid or liquid propellants carried on board the vehicle.
Nuclear propulsion
Nuclear rockets can be used only outside Earth’s atmosphere, to avoid any possibility of radioactive contamination. The possibilities that nuclear energy offers to space missions were recognized even before the discovery of nuclear fission and its use makes such missions possible, hence becoming of fundamental importance. Available technology includes both solar and nuclear thermal sources that heat hydrogen propellant to achieve high specific impulse. Of these two, only nuclear thermal propulsion is rated as a high-priority technology. Nuclear Thermal Rockets (NTR) are high-thrust propulsion systems with the potential to achieve twice the specific impulse of the best liquid hydrogen/oxygen chemical rockets.
Deep Space propulsion
For “deep space” missions, such as missions to the outer planets of our solar system, the propellant energy and mass requirements tend to be higher than for missions closer to Earth due to the higher spacecraft speed required to reduce mission duration, lower solar intensity, maneuvers involved and the generally heavier spacecraft. In many missions, natural orbits around the sun, called Hohmann trajectories, are used to send the spacecrafts from Earth orbit to target orbit with a minimum expenditure of energy. Planet movement and gravity are also used to accelerate the spacecraft without consuming energy. However, these missions last a long time. Future manned mission duration must be kept to a minimum and the most direct path is to be adopted. This requires higher energy consumption and propellant quantity. With chemical rockets and existing technologies, these missions are almost impossible.
Solar Electric Propulsion
Solar electric propulsion (SEP) uses solar power to ionize and accelerate heavy propellants, as inputs to a low thrust, fuel efficient, Ion propulsion system (IPS). The necessary electrical power comes from arrays of photovoltaic cells, so the technology is also called solar-electric propulsion. Ejecting mass at extremely high speed is the action that causes the reaction of the spacecraft accelerating in the opposite direction. The exhaust velocity of the ions is much higher than the chemical rocket exhaust velocity and that is the main reason for its higher performance. The low thrust level of ion engines means that they must run for a long time to accelerate the spacecraft to its desired velocity. Ion engines are the most efficient fuel rockets used in space today, roughly ten times more efficient than conventional chemical rocket engines.
Fusion propulsion
Miernik et al. (2011) describe how fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. A fusion reaction occurs when two atoms of hydrogen collide to create a larger helium-4 atom, releasing energy. Fusion, according to Long (2012), is the combination of two light isotopes to release energy. The enormous amount of energy created from those reactions is ejected from the engine to provide thrust. Using this type of propulsion system, a spacecraft could reach Mars in just about three months while it would take at least seven using conventional rockets.
The propellant feed systems segment is estimated to account for the second-largest market share in 2020
Space Propulsion system includes components like Nozzle, Power Processing Unit, Propellant Feed System, Rocket Motors, Thermal Control System, and Thrusters. The Propellant Feed System further studied across Combustion Chamber, Propellant Tanks, Regulators, Turbo Pump, and Valves. The Thrusters further studied across Chemical Propulsionthruster and Electric Propulsion Thruster.
By system component, the propellant feed systems segment is estimated to account for the second-largest revenue market share in 2020. The growth of this segment can be attributed to the need for proper flow of propellant delivered from the tanks to the thrust chamber, where thrusters maneuver and orbit control the satellites. Propellant feed systems consist of propellant tanks, regulators, valves, turbopumps, and combustion chambers. Cobham Mission Systems (UK), VACCO Industries (US), and RAM Company (US) are some of the players providing propellant feed systems.
Design, engineering, & operation: The fastest-growing segment of the space propulsion market, by support service
By support service, the design, engineering, & operation segment is estimated to be the fastest-growing segment of the space propulsion market. The growth of this segment can be attributed to the need for advanced design and engineering to reduce the costs and complexities of propulsion systems. The service team responds directly to customers requiring system-level technology and concept evaluation, analysis, and maturation; detailed system development and propulsion component integration; and test verification planning, evaluation, and certification. The design, engineering, & operation service also provides operational support for space transportation propulsion systems. The service provided ranges from small thrusters to large rocket engines, covering both earth storable and cryogenic propellants.
North America: The fastest-growing region in the space propulsion market
Based on the region, the space propulsion market in North America is projected to register the highest CAGR during the forecast period. The growing demand for commercial communication and imaging satellites, increasing deployment of small satellites, rising space exploration missions for interplanetary observations, and demand for resupply missions for International Space Station (ISS) are key factors expected to drive the market in North America. Globally, technological breakthroughs and resourceful insights obtained from past space missions have inspired new players to invest in this niche market.
The presence of major players and intense competition among them makes North America the most technologically advanced region. The companies in the region secure contracts from end users, such as defense, commercial, and government agencies, to deploy their satellites and launch vehicles into space by using different types of propulsion systems.
Whereas, Asia-Pacific is also anticipated to exhibit highest growth rate / CAGR over the forecast period 2020-2027. Factors such Government and private sector projects would create lucrative growth prospects for the Space Propulsion Market across Asia-Pacific region.
Industry players
The key players of global Space propulsion market have adopted various strategies to gain competitive advantage including product launch, mergers and acquisition, partnerships and agreements, investment, funding and others. For instance, In May 2020, Aerojet Rocketdyne supplied the dual chemical and electric propulsion systems for NASA’s Double Asteroid Redirection Test (DART) to the Johns Hopkins Applied Physics Laboratory (APL). However, government policies directly or indirectly impact the growth of the small satellite environment and industry at the national and international levels.
Players in the industry are acquiring smaller technology companies to increase their capabilities. For instance, Aerojet Rocketdyne acquired 3D Material Technologies (3DMT), to increase its capabilities in additive manufacturing technologies to reduce costs and improve the efficiency of proven rocket engines. Strategic acquisitions like these are expected to make the market further competitive
Some of the key players in the space propulsion market include Accion Systems Inc., Aerojet Rocketdyne Holdings Inc.(US) , Airbus Defense and Space, Ariane Group GmbH, AST Advanced Space Technologies GmbH, Blue Origin, LLC, Bradford Space, Inc., Busek Co. Inc., Cobham Mission Systems Wimborne Limited, Enpulsion GmbH, IHI Corporation (Japan), L3Harris Technologies, Inc., Maxar Technologies, Mitsubishi Heavy Industries, Ltd., Moog Inc., Northrop Grumman Corporation (US), OHB SE, RAM Company, Rocket Labs, Safran S.A.(France), Sierra Nevada Corporation, SpaceX(US) , Stanford MU Corporation, Thales Alenia Space, The Boeing Company, VACCO Industries Inc, and Yuzhnoye SDO.
References and resources also include:
https://ec.europa.eu/growth/content/electric-propulsion_en
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2175-91462018000100201