Resistojet Propulsion Systems
Space-based Resistojets
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. First flight of the APS-500 resistojet will occur in support of Atomos Space on SpaceX’s Transporter-10 in the first quarter of 2024.
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 |