The Electric Propulsion Laboratory, Inc. is Introducing its Air Breathing Electric (ABEL) Engines, and Associated Flight Qualified Sub systems, for Commercial Applications in VLEO
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These ABEL engines, and associated systems, have been under development for 25 years in EPL’s massive vacuum test facilities and include engine sizes comprising 19”, 26”, 32” and 36” inlet diameters. Power levels range from a few hundred Watts to several kW’s, with air thrust levels up to at least 0.3 N.

Highlighting the largest two of EPL’s fifteen vacuum chambers

EPL’s ABEL engines have been developed and performance optimized in simulated VLEO ground test facility conditions over altitude ranges from 240 km to 140 km. The ABEL engines can be likened to a Mach 25 Free Molecular Flow Plasma Scramjet.

Unlike current RAM compression technology efforts occurring worldwide, EPL’s ABEL engines are Flow-Through devices and thus incur no RAM inlet drag penalty due to their over 90% open area fraction to the orbital airflow. EPL Solved the more difficult problem of producing a more efficient propulsion technology.

Specifically, The ABEL engines can run on multiple propellants in addition to orbital air. When operated on xenon or krypton at altitudes above 250 km where there is insufficient air, the thrust-to-power performance is equivalent to Hall thrusters. Using its proprietary Atomic Oxygen (AO) test facilities, EPL has developed and demonstrated ABEL engine materials of construction which are virtually immune from the long term erosion effects of AO.

In support of its ABEL engine technology, EPL, a world leader in hollow cathode technology and systems, developed specialized hollow cathodes which operate from orbital air. This game changing technology enables EPL’s ABEL engines to function over a wide range of input powers without concerns of discharge plasma electron starvation. This is particularly important as the engines accommodate the varying ambient air pressure environments in VLEO associated with the earth’s oblateness, and operation over different altitude ranges to meet specific mission needs.

EPL’s unique flow-through ABEL engine results in a spacecraft design where the vehicle is integrated around a single or dual-engine configuration. This approach produces a very low drag coefficient, and a surprisingly low total mass and total cost vehicle. For example, EPL’s single ABEL engine Manta-Ray vehicle has a total mass of 80 kg while promising sustained operations at a nominal 180 km. Payload capacity for this vehicle is on the order of 10 to 20 kg. By contrast, EPL’s much larger dual 36” ABEL engine vehicle has a payload capacity of several hundred kg while promising sustained operations down to about 140 km.

During the past 25 years, EPL has demonstrated that its ABEL engines have the capability to operate from distributed point-of-use power convertors, directly from EPL manufactured battery packs, directly from solar arrays, and directly from AC power sources. This flexibility makes the ABEL engines almost agnostic in the choice of prime power. Such a capability dramatically reduces power system costs by eliminating
reliance on costly power conditioning systems.

Although EPL has a demonstrated heritage covering several specific engine sizes, EPL can manufacture engine sizes optimal to the customer mission needs. With the promise of sustained operations well below the increasingly congested LEO environment, constellations of ABEL engine propelled vehicles can support a wide range of evolving missions which are enabled by operations in VLEO.

Recognizing EPL’s history of VLEO propulsion technology development, DARPA recently awarded a $6.7M Contract to EPL under its Otter program for further optimization of its ABEL engines.

All work is performed on EPL’s campus in picturesque Monument, CO. Please contact EPL to set up an NDA to see if we can assist you in your specific VLEO mission needs.