ECAPS

History

Origins and Joint Venture (1997–2005)

The origins of ECAPS trace back to the late 1990s, when Swedish scientists initiated research into ADN as a high-energy yet environmentally safer oxidizer.

In 2000, ECAPS AB (Ecological Advanced Propulsion Systems) was established to continue the research around ADN. This reinforced experts' understanding on propellant chemistry and aerospace engineering, accelerating the industrialization of ADN technology.

In 2005, ECAPS started focusing on maturing the LMP-103S propellant and developing thruster families optimized for satellite applications.

First Demonstration and Flight Heritage

The company achieved a major milestone in 2010, when the PRISMA mission, operated by the Swedish National Space Agency (SNSA), successfully demonstrated ECAPS’s 1 N HPGP thruster in orbit - the first operational flight of an ADN-based propulsion system worldwide.

PRISMA validated both the performance and long-term stability of LMP-103S, establishing Sweden as the origin of the world’s first non-toxic spacecraft propulsion technology.

Commercial Expansion and Global Adoption (2013–2020)

Following PRISMA, ECAPS entered the commercial market with Skybox Imaging (later Planet Labs), supplying full propulsion systems for the SkySat Earth-observation constellation.

Between 2013 and 2020, ECAPS delivered 19 flight-qualified systems, demonstrating scalability, manufacturing repeatability, and operational reliability.

During this period, ECAPS propulsion modules also flew on NASA, ESA, and commercial demonstration programs, marking LMP-103S as one of the few green propellants with extensive on-orbit heritage.

Bradford Space Acquisition (2017–2023)

In 2017, ECAPS was acquired by Bradford Space Inc., under which serial production was exclusively scaled only for the 1 N thruster. During this time, ECAPS's support for missions was confined to small satellites.

Oak Universe Leadership (2023–present)

In 2023, ECAPS became part of Oak Universe AB, a Swedish-owned holding company, marking a renewed focus on R&D, sovereign propulsion capabilities, and dual-use innovation.

Under Oak Universe, ECAPS broadened its research portfolio to include auxiliary power units (APUs), gas generators, and energy systems for defense and aerospace, reinforcing Sweden’s position as a leader in advanced propulsion technologies.

Technology

High Performance Green Propulsion (HPGP) and LMP-103S

The LMP-103S propellant consists of approximately 63% ADN, 18% methanol, 14% water, and 5% ammonia.

With a density of 1.24 g/cm³, it delivers a specific impulse (Isp) of ~253 s, ~6 % higher than hydrazine.

Traditionally, hydrazine has been the leading propellant for spacecraft propulsion. Nevertheless, hydrazine is listed by the European Chemicals Agency (ECHA) as a Substance of Very High Concern (SVHC) under the European Union's REACH regulation due to its extreme environmental and health hazards.

Because of that, although temporary authorizations and exemptions exist, the European space sector is transitioning toward ADN-based alternatives such as LMP-103S to ensure regulatory compliance and reduce environmental and health risks. Its UN 1.4S classification allows safe transport under commercial air-cargo conditions, a major operational advantage.

This shift has been supported by ESA, SNSA, and European industry groups under the RHEFORM and HYPROGEO projects.

Handling and Range Demonstration

In 2015, ECAPS and NASA conducted the Green Propellant Loading Demonstration (GPLD) at U.S. launch ranges. The demonstration confirmed the safe handling and compatibility of LMP-103S with U.S. range standards.

Characteristics and Comparative Performance

LMP-103S delivers higher volumetric impulse and comparable Isp to hydrazine with far reduced toxicity. AF-M315E (ASCENT) is another propellant that has demonstrated similar attributes, but has not been as tested and operationally proven. ECAPS’s 2024–2025 Fast-Start advance gives LMP-103S systems parity in responsiveness with traditional hydrazine thrusters.

Thruster Development and Product Range

ECAPS has developed a comprehensive range of ADN-based HPGP thrusters, covering thrust levels from one newton class attitude-control engines to several hundred newton main thrusters.

The company’s technology is based on its proprietary LMP-103S monopropellant, and all engines share a modular design philosophy, allowing common injector and catalyst configurations across multiple platforms.

The first generation of ECAPS thrusters was qualified through the PRISMA mission in 2010, which validated the 1 N HPGP design and established flight heritage for the technology.

Subsequent production models have been employed on commercial constellations such as SkySat and Astroscale’s ELSA-d spacecraft, as well as in ESA and NASA demonstration programs.

In the early 2010s, ECAPS also developed a 200 N ADN-based engine as part of the Ariane 5 rocket program in cooperation with ESA and CNES. That initiative demonstrated the scalability of ADN propulsion to high-thrust applications and remains a key milestone in Europe’s transition away from hydrazine.

The company has since expanded its product line to include 5 N and 22 N thrusters, with the latter serving as the basis for the FAST rapid-start demonstrations that took place in 2025.

Development efforts now extend toward 450 N and multi-kilonewton-class engines for orbital transfer vehicles and responsive-launch architectures, combining high performance with the operational benefits of low-toxicity monopropellants.

Gas Generators and Auxiliary Power Units (APUs)

Since the success of the PRISMA mission, ECAPS has been expanding the applications of LMP-103S to power HPGP propulsion for defense applications.

In 2012, NASA Marshall Space Flight Center collaborated with ECAPS to evaluate the application of ADN propellants for legacy aircraft Emergency Power Units (EPU) and gas generators. Tests using retired F-16 EPU hardware measured ignition reliability and turbine-drive performance on LMP-103S fuel, demonstrating feasibility as a low-toxicity replacement for hydrazine. Comparative analyses included the U-2 reconnaissance aircraft’s Emergency Start System (ESS), assessing energy-density and restart requirements for high-altitude use.

These studies highlighted LMP-103S’s potential for defense gas generator and APU integration.

Building on this research and innovation, ECAPS announced in July 2025 that it was developing an LMP-103S-powered APU. demonstrator in collaboration with ISE (International Submarine Engineering) to generate electrical and pneumatic power from a compact monopropellant core.

The APU program extends ADN technology from spacecraft propulsion to terrestrial and defense energy applications, leveraging fast start-up for instant activation and continuous operation. These applications include hypersonic, underwater, and aerial vehicles.

Catalyst and Fast-Start Ignition Development

Historically, ADN propellants have required long catalyst pre-heating times, up to 30 minutes.

Between 2024 and 2025, ECAPS achieved a major advance with its Fast-Start Thruster (FAST) Catalyst Technology, enabling instantaneous ignition and reducing preheating times by over 90%.

In September 2025, the SNSA awarded ECAPS a contract under Sweden’s Dual-Use Space Technology Program to integrate the Fast-Start capability into flight-class 22 N thrusters and gas-generator systems. The program demonstrated ignition in ~48 s with a roadmap toward achieving operational readiness in ~10s.

In parallel, ECAPS successfully demonstrated a 22 N FAST experimental thruster, achieving stable combustion within 5-15s of activation - a breakthrough validating the technology for higher-thrust applications and confirming repeatability through multiple restarts and thermal cycles.

These developments establish ECAPS’s Fast-Start technology as a core differentiator for rapid-response propulsion and energy systems.

Most Fast-Start development and testing occurred at ECAPS’s Solna facilities, which host catalyst-fabrication labs, high-temperature test benches, environmental chambers, and data-acquisition systems for ignition-cycle and durability testing.

Heritage

Since its inaugural PRISMA flight, ECAPS’ HPGP technology has supported commercial and sovereign missions across Eurasia, Oceania, North America, and Southeast Asia. The following list indicates the non-classified missions that ECAPS technology has flown in.

References

References

1. "ECAPS".
2. "Oak Universe".
3. "ECAPS".
4. "Substance Information - ECHA".
5. "Testing Green Propellants with Existing Systems".
6. "Replacement of hydrazine for orbital and launcher propulsion systems {{!}} H2020".
7. "Hybrid Propulsion Module for transfer to GEO orbit {{!}} H2020".
8. Mulkey, Henry W.. (2016-07-25). "Green Propellant Landing Demonstration at U.S. Range". NASA Technical Reports Server.
9. "4.0 In-Space Propulsion - NASA".
10. (2015-09-14). "New Green Propellants Complete Milestones - NASA".
11. Mulkey, Henry. (2016-07-22). "Green Propellant Loading Demonstration at U.S. Range". American Institute of Aeronautics and Astronautics.
12. Mulkey, Henry W.. (2024-05-20). "Green Propulsion : A NASA GSFC Assessment". NASA Technical Reports Server.
13. Mulkey, Henry W.. (2024-05-20). "Green Propulsion : A NASA GSFC Assessment". NASA Technical Reports Server.
14. Ivanov, Ivan. (2025). "Hydrazine Toxicology". StatPearls Publishing.
15. Spores, Ronald A.. (2014-07-28). "GPIM AF-M315E Propulsion System". NASA Technical Reports Server.
16. Mulkey, Henry W.. (2024-05-20). "Green Propulsion : A NASA GSFC Assessment". NASA Technical Reports Server.
17. Cervone, Angelo. (2006-07-09). "Development of Hydrogen Peroxide Monopropellant Rockets". American Institute of Aeronautics and Astronautics.
18. Lohner, Kevin Andrew. "Development of a nitrous oxide monopropellant hot gas generator for rocket propellant pressurization and spacecraft thruster applications". Stanford Digital Repository.
19. "ECAPS".
20. "ECAPS".
21. "ECAPS".
22. "ECAPS".
23. Robinson, Joel W.. (2014-05-19). "Green Propulsion Auxiliary Power Unit Demonstration at MSFC". NASA Technical Reports Server.
24. "ECAPS".
25. "ECAPS".
26. "ECAPS".
27. "ECAPS".
28. "ECAPS".
29. "Teknikdemonstratorn Prisma".
30. "PRISMA (Prototype Research Instruments and Space Mission technology Advancement) - eoPortal".
31. "SkySat 3, ..., 21 (SkySat C1, ..., 19)".
32. SpaceRef. (2016-08-03). "Successful on-orbit commissioning of the SkySat-3 HPGP propulsion system".
33. "SkySat 3, ..., 21 (SkySat C1, ..., 19)".
34. Gebhardt, Chris. (2016-09-15). "Vega launches with Peru Sat-1 & SkySat 4, 5, 6, 7 payload".
35. "SkySat 3, ..., 21 (SkySat C1, ..., 19)".
36. Bergin, Chris. (2017-10-31). "Orbital ATK Minotaur-C launches SkySat mission out of Vandenberg".
37. "SkySat 3, ..., 21 (SkySat C1, ..., 19)".
38. "SpaceX launches swarm of satellites, flies rocket for third time – Spaceflight Now".
39. "STPSat 5".
40. Robinson, Joel. (2014-12-03). "ELV Payload Safety Program Workshop Green Propulsion Update". NASA Technical Reports Server.
41. "SkySat 3, ..., 21 (SkySat C1, ..., 19)".
42. (2020-06-13). "SkySats 16-18 Successfully Launch Aboard the SpaceX Falcon 9".
43. Henry, Caleb. (13 June 2020). "SpaceX launches 58 Starlink satellites, three Planet SkySats on Falcon 9".
44. "SkySat 3, ..., 21 (SkySat C1, ..., 19)".
45. (2020-08-18). "SkySat Constellation Complete: SkySats 19-21 Successfully Launch Aboard the SpaceX Falcon 9".
46. "ELSA-d Servicer (ELSA-d Chaser)".
47. (2021-03-21). "Astroscale’s ELSA-d Launch Re-scheduled for March 22, 06:07 UTC".
48. "ELSA-d (End-of-Life Service by Astroscale Demonstration) - eoPortal".
49. (2022-05-04). "Astroscale’s ELSA-d mission Has Contracted with Glavkosmos/GK Launch Services".
50. "Minotaur NROL-111 Mission".
51. "Shakespeare 1 to 3 (USA-316 to USA-318) (NROL-111) {{!}} Minotaur I {{!}} Next Spaceflight".
52. "USA 316, 317, 318 (NROL 111)".
53. "ECAPS".
54. "ArgoMoon".
55. (2019-11-14). "Fueled for Space: Aerospace Helps Artemis-Bound CubeSat {{!}} The Aerospace Corporation".
56. "ADRAS-J".
57. "ADRAS-J Mission {{!}} Astroscale's Debris Inspection Milestone".
58. "Electron KS".