Resistojet Propulsion Systems
Space-based Resistojets
Ammonia is orders of magnitude less expensive than Xenon
EPL offers complete ammonia propulsion systems at nominal power levels of 100 W and 450 W. Our propulsion system design offers wide-ranging modularity for power and propellant subsystems which enables our customers to meet their specific mission requirements. The APS units feature ammonia gas storage and flow control, and a dedicated command, control, and telemetry system. All hardware is fully qualified for space use. The nominal 450 W resistojet featured has a demonstrated life of at least 75,000 N·s with 16,500 demonstrated heat exchanger cycles. The APS 500 system offers an option of a fully integrated 440 Whr battery pack. This pack functions as the primary power source for both the spacecraft BUS and the APS 500 propulsion system.
Ammonia propulsion offers multiple advantages over Hall-Effect Thruster System including a much higher thrust which translates to about 4 times faster orbital transfer times through the Van Allen Belts. This capability means safer transfers and less stringent radiation protection requirements.
APS 100
EPL offers the battery operated APS 100. This small capable propulsion system uses liquid ammonia which self-pressurizes at 125 psia at 20 C. Ammonia was the first green propellant, it freezes at -80 C and has no condensable products to affect spacecraft surfaces. With high thrust and a specific impulse of 280 s, the APS 100 is well suited to spacecraft in the range of 10 kg to 50 kg.
| APS 100 System Wet | 2.63 kg |
| Specific Impulse | 280 s |
| Thrust | 28 mN |
| Power | 100 W |
| Turn on Time to Full Thrust from Cold | 5 s |
| Total Impulse | 2,200 N-s |
| Demonstrated Resistojet Assembly Total Impulse | 6,050 N-s |
| Idle Power Requirement | 1.5 W |
| Operating/Non-Operating Temperature Range | -25 C to 60 C / -40 C to 60 C |
| Communication Interface | RS-485 |
| Envelope | 2.5 U |
APS 500
This high performance propulsion system uses liquid ammonia which self-pressurizes at 125 psia at 20 C. Ammonia was the first green propellant, it freezes at -80 C and has no condensable products to affect spacecraft surfaces. With a thrust of 0.15 N at a specific impulse of 350 s, the APS 500 offers excellent propulsion capability for spacecraft in the range of 50 kg to 300 kg.
| APS 500 System Wet | 13.4 kg |
| Specific Impulse | 350 s |
| Thrust | 0.150 N |
| Power | 450 W |
| Turn on Time to Full Thrust from Cold | 15 s |
| Total Impulse | 25,200 N-s |
| Demonstrated Resistojet Assembly Total Impulse | 75,000 N-s |
| Idle Power Requirement | 3 W |
| Operating/Non-Operating Temperature Range | -25 C to 60 C / -40 C to 60 C |
| Communication Interface | RS-485 |
| Envelope | 27,300 cm3 |