A magnetically shielded thruster with rad-hard PPU for high thrust, high impulse missions

ACE Max is an electric propulsion system with a magnetically shielded thruster which can be configured from 800 W up to 1.8 kW. The thruster is tuned to optimize performance with krypton propellant and matched to an Apollo radiation-hardened PPU and propellant management system. Class-leading features include:

  • Can operate between 800 W and 1.8 kW (into PPU)
  • Magnetically shielded design enables 1.5 MNs total impulse
  • Multi-propellant operation with Xenon and Krypton propellants
  • 100 kRad radiation hardened, 95% efficient, single board PPU
  • Minimum 7,500 hour cathode tested to 12,000 cycles

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ACE Max Performance

PROPELLANT Krypton Xenon
INPUT POWER 1.4 kW 1.4 kW
THRUST 54 mN 60 mN
SPECIFIC IMPULSE 1,800 s 1,760 s


Magnetic shielding for 1.5 MN-s total impulse

Typically, during Hall thruster operation the plasma causes propellant ions to erode the ceramic thruster head. This is a significant life-limiting factor for thrusters like ACE. But the ACE Max thruster was designed to be magnetically shielded, resulting in an improvement in lifetime to 1.5 MN-s.

Uses 95% efficient, single board PPU, radiation hardened to 100 kRad

To deliver ACE Max as part of a fully integrated EP subsystem, Apollo has invested over $10 Million dollars to design and test a radiation hardened, ~95% efficient, single circuit board PPU. The ACE Max PPU is designed to perform in 100 kRad environments for a lifetime of 15 years. Ongoing PPU testing included six rounds of proton bombardment and one round of heavy ion testing for parts selection. This PPU design prevents gate ruptures and latchups, is tolerant of transients and upsets, and is suitable for missions from LEO through the Van Allen belts to GEO. Learn more

Choose one or two thrusters for constellations, four to eight for LEO to GEO, the Moon, or Mars

ACE Max can be configured with multiple thrusters and PPUs to handle a wide range of missions, from communication satellites with >750W Orbit Average Power up to third-stage orbit raising tugs needing 3 km/s delta-V or more. With multiple thrusters, LEO-GEO raises can take as little as 12 weeks, and missions to Low Lunar Orbit and Mars become possible starting from 500km LEO injection.

Tested to meet or exceed all customer requirements

Apollo and our suppliers are completing qualification testing in line with ESA, MIL and ISO standards. Test flow plans, test order, test procedures, and test levels are set to meet or exceed the performance, physical, electrical, environmental, thermal, and radiation requirements set by customer agreements. Learn more

High volume, high reliability acceptance testing facilities

Apollo's research and development lab has five vacuum chambers and one thermal-vac chamber, allowing for hundreds of tests per week. This has enabled the development of new system designs in weeks instead of years. These facilities are fault-tolerant by design and able to grow to enable acceptance testing of hundreds of systems per month. Learn more

Manufactured in the US and flight ready in 2020

Apollo has partnered with a high-volume aerospace manufacturing partner based in Silicon Valley. Apollo’s manufacturing partner specializes in high reliability aerospace and defense products and has the capacity to produce hundreds of units per month to Apollo Fusion customer specifications. Learn more

  • Manufacturing partner is ISO9001, AS9100 certified
  • Manufacturing process based on statistical process control
  • Apollo has offices on-site at CM facilities