ARCAspace
ARCAspace, formally known as the Romanian Cosmonautics and Aeronautics Association, is a non-profit aerospace research organization headquartered in Râmnicu Vâlcea, Romania, specializing in the development of propulsion systems, launch vehicles, and related technologies for space access, aeronautics, and defense applications.[1][2] Founded in 1999 by a group of Romanian engineering students, the organization has pursued innovative, low-cost approaches to rocketry, emphasizing reusable and environmentally friendly designs such as water-based propulsion to minimize reliance on traditional chemical fuels.[3][4] Key achievements include its participation in the 2004 Ansari X Prize competition, during which ARCAspace successfully launched the Demonstrator 2B sounding rocket from Black Sea coastal facilities, marking an early milestone in private Romanian spaceflight efforts.[2] The group has since conducted multiple suborbital tests, including stratospheric balloon missions and the development of engines like the Executor series, which prioritize efficiency through hybrid and electric augmentation.[2] Currently, ARCAspace is advancing the EcoRocket, a compact orbital launch vehicle designed for small payloads with a focus on cost reduction and reduced emissions via non-toxic propellants.[5] While ambitious in scope—encompassing ventures like the ArcaBoard personal flight device and potential expansions into U.S. operations—the organization's progress has drawn scrutiny for optimistic timelines and unconventional designs, though empirical tests substantiate core technical validations.[6][7][8]History
Founding and Early Demonstrator Rockets (1999–2004)
ARCAspace was founded in 1999 as a non-governmental organization in Romania by engineer and entrepreneur Dumitru Popescu, along with a group of colleagues primarily from the Aerospace Engineering faculties of universities in Bucharest and Sibiu, as well as some from Theology backgrounds.[9] The initiative stemmed from an informal group formed in 1998 aimed at advancing amateur rocketry and aeronautics in the country, driven by Popescu's vision for low-cost space access technologies.[9] Initially operating on limited resources, the organization focused on conceptual designs and small-scale testing to build foundational expertise in solid-propellant rocket systems. During its early years, ARCAspace developed the Demonstrator series of suborbital sounding rockets as proof-of-concept vehicles for reusable and cost-effective propulsion, targeting participation in the Ansari X Prize competition for private suborbital human spaceflight.[2] The Demonstrator 1 prototype, a single-stage solid-fuel rocket intended for low-altitude tests, was designed but never launched due to funding and technical constraints.[10] This design served as the technical foundation for subsequent iterations, emphasizing lightweight composites and simple avionics to achieve altitudes exceeding 10 kilometers. The program's milestone came with the Demonstrator 2B, ARCAspace's first successful rocket launch on September 9, 2004, from Cape Midia Air Force Base on Romania's Black Sea coast.[11] Powered by a custom solid-propellant engine, the 2.5-meter-long vehicle reached an apogee of approximately 30 kilometers, validating the organization's in-house propulsion and recovery systems during the Ansari X Prize effort.[11] [12] Ground tests of the Demonstrator 2B engine preceded the flight, confirming thrust levels around 5 kN and structural integrity under operational stresses.[13] This achievement marked Romania's first private rocket launch and demonstrated ARCAspace's capability for end-to-end vehicle development despite operating as a volunteer-driven NGO with minimal external support.Suborbital Advancements with Stabilo and Helen (2005–2010)
Following the Ansari X Prize efforts, ARCAspace developed the Stabilo, a suborbital manned vehicle intended for launch from the stratosphere using a solar balloon to achieve altitudes exceeding 100 km.[14] The project emphasized testing payload transport, recovery systems, and hybrid propulsion, with the vehicle measuring 6 meters in length, 1.3 meters in diameter, and a launch mass of 1,000 kg.[14] A solar balloon with a volume of 350,000 cubic meters elevated the capsule to approximately 23 km before rocket ignition, targeting speeds up to 1,200 m/s.[14] In 2006–2007, ARCAspace constructed the world's largest solar balloon to loft the Stabilo crew capsule into the stratosphere.[2] Mission 1 on December 2, 2006, reached 14,700 m, traveled 68 km, and successfully demonstrated payload deployment and recovery.[14][15] Mission 2, launched September 27, 2007, from Cape Midia Air Force Base over the Black Sea, attained 12,000 m with the full vehicle; recovery was assisted by the Romanian Navy after 1.5 hours.[14][15] These tests validated stratospheric ascent and descent procedures but fell short of suborbital apogees due to balloon performance limits.[2] Transitioning toward lunar competition goals, ARCAspace initiated the Helen rocket in 2008 as part of its entry into the Google Lunar X Prize, serving as an avionics and propulsion testbed for the European Lunar Lander vehicle.[2][16] Helen comprised two variants: a three-stage configuration launched via solar balloon targeting 80 km, and Helen 2, a two-stage system with spherical tanks deployed from a helium balloon.[16] Helen tests encountered setbacks, including Mission 3 on November 14, 2009, canceled due to balloon entanglement, and Mission 4 aborted from balloon rupture.[16] Mission 5 successfully validated avionics at 5,200 m using a hot air balloon, despite minor anomalies.[16] Mission 4B in 2010 achieved 40 km (131,000 ft) with Helen 2's first stage firing, marking the competition's inaugural powered flight, though the payload was unrecovered due to parachute failure.[16][2] These suborbital efforts advanced ARCAspace's hybrid rocket technology and high-altitude operations, informing subsequent orbital ambitions.[16]Expansion into Aircraft, Engines, and Haas Rockets (2011–2013)
In 2011, ARCAspace advanced its IAR-111 Excelsior project, completing the capsule structure on July 5, weighing 1,100 lb (500 kg) and designed for a crew of two with integrated ejection seats and dual rocket-powered parachutes for recovery.[17] The rear fuselage section molds were finalized on September 12, supporting the rocket-plane's composite airframe optimized for suborbital flights. Computational fluid dynamics simulations concluded on September 18, incorporating design refinements such as lowering the engine position by 30 cm and increasing wingspan by 90 cm to enhance aerodynamic performance. A drop test of the capsule from 2,300 ft (700 m) using a Mi-17 helicopter on September 29 demonstrated successful deployment and landing via rocket-powered parachute, validating recovery systems.[17] The Executor rocket engine, intended for both the IAR-111 and emerging orbital vehicles, entered production in December 2011, with the first unit completed on August 16, 2012, delivering 53,000 lbf (24,000 kgf) thrust at a weight of 210 kg for a thrust-to-weight ratio of 110 using liquid oxygen and kerosene propellants.[17] This lightweight composite engine represented a shift toward pressure-fed designs with high efficiency, including tests of an ultra-low mass kerosene tank on March 27, 2012, achieving a structure-to-fuel mass ratio of 0.00082. By 2013, a second Executor variant was integrated onto a test stand at ARCA's Cosmobaza facility for ground validation, though full hot-fire testing occurred later.[17][18] Parallel to engine and aircraft efforts, ARCAspace introduced the Haas rocket family in 2012, debuting the Haas 2C orbital launcher on June 1 with a gross liftoff weight of 35,000 lb (16,000 kg) capable of delivering 880 lb (400 kg) to low Earth orbit, initially targeting the CubeMessenger satellite as its first payload.[17] The suborbital Haas 2B complemented the series, both leveraging Executor propulsion and composite structures for cost reduction. Development emphasized single-stage-to-orbit potential in later iterations like the Haas 2CA, though the program faced delays from concurrent projects including ESA collaborations.[19] ![Haas 2C rocket unveiled in Victory Square, Bucharest]float-rightStratospheric and Launch Assist Systems (2014–2019)
In 2014, ARCAspace initiated development of the AirStrato, a solar-powered high-altitude long-endurance unmanned aerial vehicle intended for stratospheric operations as a balloon replacement for payload delivery and observation missions.[20] The platform targeted altitudes up to 18 km with endurance exceeding 20 hours, depending on solar conditions, and supported payloads up to 45 kg via satellite or GSM control.[20] Its design emphasized low-cost accessibility, featuring a 16 m wingspan, 230 kg maximum takeoff weight, and cruise speeds around 152 km/h at operational altitude.[20] The first AirStrato prototype, equipped with fixed landing gear, completed its maiden flight on February 28, 2014.[21] Subsequent iterations eliminated landing gear in favor of catapult-assisted launches and parachute recovery to minimize structural mass and enable operations from remote sites.[20] ARCAspace projected commercial production of AirStrato variants, including the Pioneer and Explorer models, to commence in the United States by mid-2015, positioning it for civil and defense applications in telecommunications, surveillance, and environmental monitoring.[22] In 2017, the AirStrato program was acquired by a U.S. telecommunications firm, concluding ARCAspace's direct involvement.[20] By late 2018, ARCAspace shifted focus toward propulsion innovations, initiating ground tests in July for the Launch Assist System (LAS), a water-steam rocket technology designed to augment orbital launch vehicles.[4] Announced publicly in early 2019, LAS employed superheated water (heated to 250°C with benign additives) as a clean propellant, aiming to either cut polluting emissions in hybrid stacks by 25-50% or boost payload capacity by approximately 30% without environmental penalties.[4] The system prioritized high thrust-to-weight ratios over specific impulse (targeting 50-60 seconds), utilizing composite structures and self-pressurizing designs for expendable bell-nozzle or reusable aerospike configurations.[4] LAS development culminated in static firings, including an October 24, 2019, aerospike engine test that achieved 15% higher specific impulse compared to equivalent bell-nozzle variants, validating its potential as a reusable booster for subsequent rocket stages.[4] This period marked ARCAspace's pivot from pure stratospheric platforms to integrated launch enhancement technologies, leveraging non-toxic propellants to address sustainability challenges in access to space.[4]Shift to EcoRocket, Asteroid Mining, and Diversification (2020–Present)
In November 2020, ARCAspace initiated the EcoRocket program to develop low-cost, ecologically sustainable orbital launch vehicles, building on prior Launch Assist System technology. The program emphasizes reusability for the first two stages using water-based propulsion, paired with an expendable third stage employing 95% hydrogen peroxide and kerosene, resulting in only 2% of emissions classified as polluting. Vehicles incorporate pressure-fed engines and lightweight composite structures for enhanced efficiency.[5][2] The EcoRocket lineup comprises a demonstrator for small payloads to low Earth orbit (LEO) and the EcoRocket Heavy, designed to deliver 24 metric tons to LEO at a projected cost of $5.06 million per launch. Launches support vertical trajectories from sea or land platforms, with development encompassing ground tests, sea trials, and flight sequences; a 2022 upgrade introduced the Produs 3 configuration featuring wingless active flight control. Initial orbital flight targets shifted from 2022 to 2024 amid Black Sea regional conflicts, with testing continuing into subsequent years.[5][23] Parallel to EcoRocket advancements, ARCAspace launched the AMi Exploration initiative in 2022 as a twelve-year asteroid mining endeavor spanning 2022–2033, targeting $1 billion in precious metals extraction by 2033 through profitable operations. The program deploys the AMi Cargo spacecraft—capable of 20 metric tons to LEO—for reconnaissance and mining, launched via EcoRocket Heavy, with ore return commencing in 2029 and the inaugural full mission in 2031 aiming for 1,000–2,500 kg of platinum-group metals valued at $34–85 million. Total projected costs reach $207 million, including $100 million required by 2029 for mission execution.[24] This period marked ARCAspace's diversification beyond traditional suborbital and stratospheric systems into orbital launch services, deep-space resource utilization via AMi, and defense technologies, positioning the organization as a non-profit research entity advancing space exploration, aeronautics, and military applications. EcoRocket variants have been adapted for dual-use roles, such as target vehicles for anti-missile testing, expanding commercial and strategic revenue streams.[1][5]Organization and Operations
Leadership and Structure
ARCAspace functions as a high-tech research non-profit organization headquartered in Stoenești, Vâlcea County, Romania, with a for-profit subsidiary known as ARCA Space Corporation incorporated in New Mexico, United States, during 2013–2016.[2] The entity maintains dual operations across these locations, focusing on research and development in aerospace technologies while leveraging the U.S. arm for commercial and contractual pursuits, such as past engagements with DARPA and the U.S. Army.[2][25] Dumitru Popescu, a Romanian engineer and entrepreneur, founded ARCAspace in 1999 as a non-governmental organization and continues to lead it as president and chief executive officer.[26][27] Popescu oversees strategic direction, including technology development and public engagements, as evidenced by his representation of the company at international forums like the Asia-Pacific CEO Association's Global High-End Manufacturing Summit in 2025.[28] In 2015, Chris Lang, founder and CEO of The LNG Company, joined as chief operating officer after serving on the board since March of that year, tasked with managing U.S.-based operations during the company's expansion to Las Cruces, New Mexico.[25] Public records indicate a lean executive structure centered on Popescu, with limited disclosure of additional board members or senior personnel beyond historical references to past board involvement in internal disputes resolved by 2018.[27][29] This setup aligns with the organization's small-scale operations, employing between 11 and 50 personnel focused on engineering and prototyping.[30]Funding and Business Model
ARCAspace functions as a non-profit research organization, with its operations sustained primarily through private funding sources, including donations, sponsorships, and contributions from founder Dumitru Popescu.[2][1] The entity has conducted multiple test launches and development programs without relying on government subsidies, explicitly covering associated expenses via internal private resources.[31] In an effort to expand financing, ARCA Space, the associated U.S. corporation, pursued an equity crowdfunding round in February 2016, though the amount raised remains undisclosed and appears limited relative to industry peers.[32] No significant venture capital investments or large-scale institutional funding have been reported, distinguishing ARCAspace from venture-backed NewSpace competitors and underscoring its bootstrapped approach amid constrained resources.[30] The business model emphasizes technology development for space exploration, aeronautics, and defense, with non-profit status facilitating research into innovative propulsion and vehicles without immediate profit mandates.[1] Long-term commercialization prospects center on asteroid mining via the AMi Exploration program, which envisions revenue generation through extraction and return of platinum-group metals and other valuables from near-Earth objects, potentially yielding millions per mission once operational.[10] Complementary efforts include advancing reusable launch systems like the EcoRocket family for prospective payload services, though no orbital successes or contracts have materialized to date, positioning revenue ambitions as aspirational amid ongoing suborbital demonstrations.Launch Vehicles and Aircraft
Haas Rocket Family
The Haas rocket family comprises a series of suborbital and orbital launch vehicles developed by ARCAspace, named after Conrad Haas (1509–1579), an Austrian-Romanian innovator credited with early rocket designs in medieval manuscripts. Introduced in 2012, the family emphasizes lightweight composite structures for cost reduction and includes variants such as the suborbital Haas 2B and orbital Haas 2C, with plans for air-launch integration using carrier aircraft like the IAR-111. These designs targeted payloads of up to 400 kg to low Earth orbit (LEO) for the Haas 2C, which had a gross liftoff mass of 16,000 kg.[19][2][17] The Haas 2B served as a single-stage suborbital vehicle for high-altitude sounding missions, while the Haas 2C was configured as a two-stage orbital launcher capable of delivering 400 kg to LEO. Both relied on liquid-fueled engines, with the family initially developed in parallel with ARCAspace's Google Lunar X Prize efforts and national space ambitions. Public displays, such as the Haas 2C's debut in 2012, highlighted the rockets' modular architecture, but no flight tests were conducted for these early variants.[17][33] In March 2017, ARCAspace unveiled the Haas 2CA, an advanced single-stage-to-orbit (SSTO) variant powered by a linear aerospike engine for altitude-compensating thrust efficiency. The company projected a 100 kg payload to LEO at a launch cost of $1 million, leveraging composite materials for a dry mass under 2,000 kg and enabling potential reusability with 24-hour turnaround times. Despite these ambitions, the Haas 2CA remained in development without successful orbital flights as of 2025, evolving into the EcoRocket program focused on reduced environmental impact and small satellite deployment.[34][35][36]EcoRocket Family
The EcoRocket family comprises a series of launch vehicles developed by ARCAspace since 2020, emphasizing ecological propulsion, reusability, and low-cost operations through water-based systems for initial stages. These rockets employ superheated steam generated via electric heating of water as the primary propellant for the first two stages, minimizing atmospheric pollution to approximately 2% of total mass, with the third stage using hydrogen peroxide and kerosene ignited above 65 km altitude. The design prioritizes composite materials for lightweight construction and pressure-fed systems to simplify operations.[5] The EcoRocket Demonstrator serves as the foundational prototype for orbital launches, configured as a three-stage vehicle with reusable first and second stages recoverable via parachute splashdown. Development began in 2020 with Produs 1, progressing to Produs 2 in 2021 for propulsion and flight control validation through ground and sea tests, and Produs 3 in 2022 incorporating wingless active flight controls and an enlarged third-stage diameter. The system targets altitudes of 220 km and velocities up to 28,500 km/h, though specific payload capacities for the Demonstrator remain undisclosed; initial orbital flight plans, delayed from 2022 due to regional geopolitical factors, aim for 2024. Ongoing tests include full-duration burns at 60% thrust and vehicle upgrades for sequential flight operations.[5] EcoRocket Heavy extends the Demonstrator's propulsion modules (PMs)—small, 1.2 m diameter units integrating tanks and engines—into a massively scaled configuration for heavy-lift missions, comprising 540 PMs across three stages (420 in the first, 90 in the second, 30 in the third). This yields a total launch mass of 5,443 tons, empty mass of 188 tons, 34.5 m diameter, 28 m length, and 12,600 tons of thrust, enabling 24 tons to low Earth orbit (LEO). Reusability is inherent in the modular PM design, facilitating easier transport, assembly, and refurbishment to achieve unprecedented cost per kilogram claims. Primarily intended for deploying 20-ton AMi Cargo spacecraft in asteroid mining operations, the first five PMs were presented on July 1, 2023, with the Demonstrator as a precursor for validation.[37] The Commercial EcoRocket (CER) subseries adapts the technology for suborbital applications, including target rockets for military training and civilian research. Variants include CER-160 for simulating artillery trajectories like those of M270 MLRS or HIMARS systems, with dual launches demonstrated in 2024; CER-500 and CER-1200 for extended-range targets. The CER-1200TR, a 1,200 mm caliber model, is undergoing military homologation as an ecological, cost-effective alternative with rapid firing capabilities. These systems leverage the same water-based propulsion for reduced environmental impact and operational simplicity, with tests confirming two-hour turnaround times between launches.[38][39]IAR-111 Rocket Plane and AirStrato UAV
The IAR-111 Excelsior was a suborbital rocket plane project initiated by ARCAspace in 2010, designed for commercial space tourism flights or as a reusable first stage for the Haas 2C orbital rocket.[17] The vehicle featured a composite capsule structure weighing 500 kg when fully equipped, capable of accommodating two crew members with an integrated ejection system using rocket-powered parachutes.[17] On September 26, 2011, the capsule underwent a successful drop test from 700 meters using a Mi-17 helicopter, deploying parachutes for a safe landing as part of Mission 6.[17] Propulsion was planned around the Executor rocket engine, delivering 53,000 lbf of thrust with a maximum burn time of 190 seconds and a dry mass of 210 kg, fueled by kerosene stored in lightweight composite tanks optimized for a structure-to-fuel mass ratio of 0.00082.[17] Computational fluid dynamics simulations completed in September 2011 refined the airframe, including lowering the engine position by 30 cm and increasing wingspan by 90 cm for improved aerodynamics.[17] Rear fuselage molds were finalized in September 2011, but no powered flights occurred, and the project appears to have been discontinued after 2012 as ARCAspace shifted priorities to rocket families and other aircraft.[17][40] The AirStrato was an electric-powered, solar-assisted high-altitude long-endurance (HALE) unmanned aerial vehicle (UAV) developed by ARCAspace starting around 2013, aimed at bridging the gap between expensive military UAVs and low-cost commercial options for applications such as border surveillance, disaster monitoring, and environmental assessment.[20] The prototype featured a 16 m wingspan, 7 m length, 1.6 m height, and 19.2 m² wing area, with an empty weight of 185 kg, maximum payload of 45 kg, and maximum takeoff weight of 230 kg.[20] It was equipped with six Robbe 8085/10 electric motors providing 20 kgf thrust each at sea level, supplemented by 2,800 W of solar cells for extended endurance.[20] Performance specifications included a flight ceiling of 18,000 m, takeoff speed of 54 km/h, cruise speed of 152 km/h at altitude, maximum speed of 170 km/h, 20-hour endurance (season-dependent), 1,200 km ferry range, and 3 m/s climb rate; avionics comprised an EMAC VDX PC/104 flight computer and XSens MTI-10 inertial measurement unit.[20] Initial ground tests in 2014 included taxiing on February 14 and a short flight to 25 m altitude from rough terrain, initially using landing gear before transitioning to a catapult launch system (Accelerator) to reduce weight.[40] Flight testing expanded in 2015 at Spaceport America in New Mexico, with plans for production in the United States, though progress was limited.[41] The project was acquired in 2017 by a U.S. telecommunications company, ending ARCAspace's direct involvement.[20]Other Systems: ESA Drop Test, A1 Interceptor, and AMi Cargo
ARCAspace developed the High Altitude Drop Test (HADT) program for the European Space Agency (ESA) to evaluate the parachute system of the ExoMars spacecraft, which launched in 2016.[2] In 2013, ESA contracted ARCAspace to construct a Drop Test Vehicle (DTV) for atmospheric reentry simulations, deploying parachutes from a high-altitude balloon at approximately 30 km to mimic Mars entry conditions.[35] The program included a balloon flight on September 16, 2013, from an undisclosed site, where the DTV successfully tested parachute deployment mechanisms under subsonic and supersonic regimes.[42] The A1 Interceptor is a family of low-altitude anti-ballistic missile defense systems designed by ARCAspace to counter hypersonic and supersonic threats, including those with nuclear or multiple independently targetable reentry vehicle (MIRV) payloads.[43] The A1A variant targets extremely low-altitude intercepts for protecting compact, high-value assets such as military installations or infrastructure, utilizing a kinetic or explosive warhead for terminal-phase neutralization.[44] The A1B extends capabilities with a deployable dome of interceptors for area defense against salvos. Development began around 2021 in collaboration with General Astronautics, with a fit check to launch structures completed on May 3, 2024, and the first test launch designated as Mission 19 in July 2024 from a ground-based site.[31] The system has attracted interest from NATO member militaries for its canister-launched, rapid-response design integrated with artillery rocket systems like the CER-160TR.[45] The AMi Cargo is a reusable spacecraft within ARCAspace's Asteroid Mining Initiative (AMi), capable of delivering 20 metric tons to low Earth orbit (LEO) for reconnaissance, asteroid interception, and resource extraction missions.[46] Launched as the primary payload atop the EcoRocket Heavy, it features modular propulsion for orbital maneuvers, sample collection tools, and a return capsule for Earth reentry without parachutes in updated designs, relying on precision aerobraking and landing systems.[47] First conceptualized in 2022 as part of a 12-year program targeting metallic asteroids for platinum-group metals and water, the vehicle supports in-situ resource utilization to reduce mission costs, with initial flights planned post-2030 following EcoRocket qualification.[48] Economic projections emphasize profitability through low-propellant, eco-friendly operations, though viability depends on validated orbital mining technologies.[10]Propulsion Systems
Traditional Engines: Executor and Venator
The Executor is a linear aerospike rocket engine developed by ARCAspace primarily for the first stage of the Haas 2CA single-stage-to-orbit vehicle. It employs hypergolic ignition with hydrogen peroxide (HTP) as the oxidizer and RP-1 (refined kerosene) as fuel, enabling a pressure-fed or gas-generator cycle configuration. The engine delivers 22,920 kgf (approximately 225 kN) of thrust at sea level and 33,500 kgf (approximately 328 kN) in vacuum, with corresponding specific impulses of 230 seconds and 314 seconds.[19] Its design incorporates 16 parallel combustion chambers along a truncated aerospike nozzle, which provides altitude compensation for improved efficiency across varying atmospheric pressures; thrust vector control is achieved via differential throttling of individual chambers rather than mechanical gimbaling, reducing complexity and mass. Development of the Executor commenced in the early 2000s, with ground tests demonstrating a thrust-to-weight ratio exceeding 100 and burn durations up to 190 seconds using lightweight composite materials and aluminum alloys.[17] The Venator engine, planned as an upper-stage propulsor for multi-stage Haas variants such as the Haas 2C, is a simpler pressure-fed bipropellant engine using liquid oxygen (LOX) and RP-1. It produces around 50 kN of thrust, suitable for vacuum operations following separation from lower stages.[49] Unlike the more ambitious Executor, the Venator prioritizes reliability and low development cost through pressure-fed architecture, avoiding turbopumps. Publicly available specifications remain limited, reflecting ARCAspace's pivot toward non-chemical propulsion paradigms like steam-based systems in the EcoRocket family by the mid-2010s, which rendered these kerolox engines largely archival.Innovative Propulsion: LAS, Steam-Based, and Modular Systems
The Launch Assist System (LAS) represents ARCAspace's effort to develop an electrically powered, water-based booster for orbital launches, functioning as a first-stage accelerator that superheats water into high-velocity steam or plasma via electric arcs to produce thrust. Introduced in white papers around 2019, the system integrates with aerospike nozzles to maintain efficiency across varying atmospheric pressures, theoretically offering 15% higher specific impulse than equivalent bell-nozzle designs. Ground tests of the LAS 25D engine variant commenced on May 5, 2019, demonstrating sustained operation with water as the sole propellant, eliminating the need for chemical oxidizers.[4][50] ARCAspace claims the LAS enables reusable, low-cost staging by leveraging abundant water and electrical energy, with underwater engine starts validated in 2023 to support sea-launch concepts.[51] Steam-based propulsion underpins ARCAspace's EcoRocket family, where batteries or ground-supplied power rapidly heat water to supercritical steam states, expanding it through nozzles for suborbital or orbital ascent in the initial stages. This ecological approach, avoiding hypergolic or cryogenic chemicals, prioritizes reusability and minimal environmental impact, with the first two EcoRocket stages designed for recovery after generating water vapor exhaust. Development accelerated post-2019, with reaction control system tests in November 2021 confirming steam thruster viability, and plans for a suborbital EcoRocket Nano flight in Mission 15 targeting space access solely via steam propulsion.[5][52] Critics note thermodynamic challenges in scaling electrical heating for vacuum performance without prohibitive energy densities, as independent analyses question in-flight sustainability beyond short bursts.[53] Modular propulsion systems in ARCAspace's designs, particularly for EcoRocket Heavy, cluster identical steam-based thruster units into scalable arrays, allowing incremental payload capacity from 5-module orbital configurations to larger variants for asteroid missions. Five flight-ready modules were publicly demonstrated on July 1, 2023, at Cosmobase, each capable of independent operation and forming a standalone EcoRocket 5 vehicle with orbital potential when stacked. This architecture emphasizes redundancy, simplified manufacturing, and cost reduction through mass-produced units, aligning with ARCAspace's AMi cargo goals for in-orbit refueling.[54][55] The modularity extends LAS principles, enabling hybrid electric-steam clusters for boosted efficiency, though full integration remains in prototyping without verified flight data.[56]Missions and Tests
Early Suborbital Missions (Missions 1–6)
Mission 1, conducted on December 2, 2006, involved the stratospheric flight of the Stabilo capsule using a large solar balloon launched from Onești, Bacău County, Romania, reaching an altitude of approximately 14,700 meters.[14] The test demonstrated ARCAspace's ability to transport and recover a reentry capsule in a high-altitude environment, validating key systems for future suborbital vehicles without a rocket launch.[14] Mission 2, launched on September 27, 2007, from Cape Midia Air Force Base, utilized another solar balloon to elevate the Stabilo 1B vehicle to 22,000 meters over the Black Sea before initiating a suborbital rocket phase.[57] The mission tested the complete Stabilo spacecraft configuration, including carrier balloon operations and ship recovery, though specific rocket performance data from this flight remains limited in public records.[14] Subsequent missions shifted toward integrated rocket-balloon systems for the Helen series. Mission 3, attempted on November 14, 2009, aimed to loft the three-stage Helen rocket—comprising Demonstrator 2, 2B, and 2C stages—via the world's largest solar balloon (7,060,000 ft³ volume) to 14,000 meters for an avionics payload test including the ELL system.[17] The rocket ignition sequence succeeded, but the mission was aborted due to balloon fabric entanglement, exacerbated by insufficient solar heating as sunset approached, preventing ascent.[17] Mission 5, on April 28, 2010, served as a preparatory avionics validation for Helen 2, employing a manned hot air balloon to carry the Helen capsule to 17,000 feet.[17] Telemetry, TV transmission, and command systems were tested successfully overall, though some mixed results were noted in data reception.[17] Mission 4 followed on August 4, 2010, attempting a helium balloon loft for the Helen 2 rocket but ended in failure when the balloon ruptured during inflation.[17]| Mission | Date | Vehicle/System | Key Objective | Outcome |
|---|---|---|---|---|
| 1 | December 2, 2006 | Stabilo capsule + solar balloon | Stratospheric capsule flight and recovery | Successful ascent to 14,700 m; systems validated[14] |
| 2 | September 27, 2007 | Stabilo 1B + solar balloon | High-altitude loft and suborbital test | Reached 22,000 m; configuration tested[57] |
| 3 | November 14, 2009 | Helen rocket + solar balloon | Balloon-lofted rocket launch with avionics | Aborted: balloon entanglement and low heating[17] |
| 4 | August 4, 2010 | Helen 2 + helium balloon | Balloon-lofted rocket test | Failed: balloon rupture[17] |
| 5 | April 28, 2010 | Helen capsule + hot air balloon | Avionics systems check | Mostly successful; minor data issues[17] |
| 6 | September 26, 2011 | IAR-111 Excelsior capsule | Helicopter drop test for rocket-plane recovery | Successful parachute deployment and landing[17] |