History

ECAPS AB is a

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

spacecraft

propulsion Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived from ...

company, established in 2000 as a joint venture between the

Swedish Space Corporation The Swedish Space Corporation (SSC) provides space subsystems, space and satellite operations, rocket and balloon systems including experiment equipment, launch services, aerospace engineering services as well as airborne maritime surveillance s ...

(SSC) and

Volvo Aero Volvo Aero was a Swedish aircraft, guided missiles and rocket engine manufacturer. It became ''GKN Aerospace Engine Systems'' following the company's acquisition by British engineering conglomerate GKN during 2012. It was originally establis ...

with the goal of developing and commercializing in-space

thruster Thruster may refer to: Propulsion devices A thruster is a propulsive device used by spacecraft and watercraft for station keeping, attitude control, in the reaction control system, or long-duration, low-thrust acceleration. * Reaction eng ...

technology using a low toxicity Ammonium dinitramide (ADN) based liquid

monopropellant Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with bipro ...

called LMP-103S. In 2006 ECAPS became a fully owned subsidiary of SSC. In June 2010 the PRISMA mission launched ECAPS' first flight 1N thrusters which were successfully operated until the decommissioning of PRISMA in 2015. In July 2017, SSC sold ECAPS t
Bradford Engineering
based in the Netherlands which re-branded the company as Bradford ECAPS.

Adoption in Industry

ECAPS technology (thrusters +

propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the ...

) has successfully flown on the following missions: {, class="wikitable" , +Space Missions with ECAPS Technology !Name !Organization !Launch Date !Organization Type , - , PRISMA , SSC , June 2010 , Government , - , SkySat-3 , Skybox Imaging , June 2016 , Commercial , - , SkySat-4, 5, 6, 7 , Skybox Imaging , Sept 2016 , Commercial , - , SkySat-8, 9, 10, 11, 12, 13 ,

Planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a ...

, Oct 2017 , Commercial , - , SkySat-14, 15 ,

, Dec 2018 , Commercial , - , STPSat-5 , Sierra Nevada Corp , Dec 2018 , Government , - , SkySat-16, 17, 18 ,

, June 2020 , Commercial , - , SkySat-19, 20, 21 ,

, upcoming , Commercial , - , GEOSat-1
Astranis
, upcoming , Commercial , - , ArgoMoon , Argotec , upcoming , Government , - , ELSA-d
Astroscale
, upcoming , Commercial , - , SL-OMV , Moog , upcoming , Commercial

Thruster Description

The ECAPS thruster technology produces thrust by thermally and catalytically decomposing, igniting, combusting, and exhausting monopropellant LMP-103S fed into the thruster's reactor. LMP-103S is a 'green' high performance storable liquid propellant based on ammonium dinitramide (ADN) blended with fuel, stabilizer and solvent. The thruster is composed of:

Flow Control Valve (FCV)

A series redundant, normally closed, solenoid valve with

PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chem ...

seat material.

Thrust Chamber Assembly (TCA)

Propellant transfer assembly

Composed of the FCV interface including two (redundant seal) EPDM O-rings, the feed tube, the feed tube heat-sink, and the injector head.

Thermal Stand-off

Structural member between the FCV and the main thruster elements, which serves as a heat barrier. It is sized to suppress severe heat soak back from the thruster to the FCV.

Thrust Chamber

Houses the staged reactor, which houses the propellant

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

. The thrust chamber upstream side is brazed to the injector head. The nozzle is an integrated part of the thrust chamber on the down-stream side and is conical with an exit-to-throat area ratio of 100:1. The thrust chamber is made of

iridium Iridium is a chemical element with the symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of ...

lined

rhenium Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-gray, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is on ...

to withstand the high temperature reaction products of propellant combustion and the resulting thermal cycling.

Reactor Heater

Reactor heater is embedded in an

Inconel Inconel is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys. Inconel alloys are oxidation- corrosion-resistant materials well suited for service in extreme environments subjected ...

tube with a ceramic insulator. The heater is a coiled tube which is integrated into heater carrier, which in turn is integrated via thermally conductive parts into the injector head.

Reactor Thermocouple

Type K ( chromel/ alumel) and is embedded in an Inconel tube with a magnesium oxide insulator. The thermocouple is used for monitoring and controlling the pre-heating temperature.

LMP-103S Propellant Description

Development of the storable liquid

blend LMP-103S began in 1997 between the

and the Swedish Defense Research Agency. The top design priorities were to improve performance and reduce handling hazards as compared to

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazin ...

. Long term ground storage testing of the LMP-103S propellant in a flight-like system began in October 2005 and has demonstrated no measurable degradation or pressure build-up. Transport is approved as an UN/DOT1.4S article. Air transport on commercial flights of the LMP-103S propellant has been performed to the United States, the United Kingdom, Japan, Switzerland, Russia, India French Guiana, and within Sweden. The propellant is 63.0% ADN, 14.0% water, 18.4% methanol and 4.6%

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogeno ...

by weight. LMP-103S has different properties than other traditional propellants such as

and

nitrogen tetroxide Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russia rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium ...

. The latter are pure liquids, which (except for trace contaminants) can be completely evaporated, leaving no residues. In contrast, LMP-103S is a mixture comprising a high concentration of ADN "salt" dissolved in a mixture of solvents. Evaporation leads to a loss of solvents and thereby a changed composition of the solution (the ADN salt has no vapor pressure, so it only exists in solid or dissolved form). The solution does not have a distinct freezing point, but rather a temperature when the solution becomes saturated and solid ADN crystals will start to form in the liquid solvents (this is, however, a reversible phase separation).

References

* http://www.ecaps.space/ Company homepage
On-Orbit Operation and Performance of Ammonium Dinitramide (ADN) Based High Performance Green Propulsion (HPGP) Systems
JPC 2017 conference paper
Growing Constellation of Ammonium Dinitramide (ADN) Based High Performance Green Propulsion (HPGP) Systems
JPC 2018 conference paper Propulsion Spacecraft attitude control Monopropellant rocket engines