Facts About the ASCENT Propellant
ASCENT (Advanced Spacecraft Energetic Non-Toxic) propellant, formerly known as AF-M315E, is an advanced monopropellant formulation developed by the Air Force Research Laboratory (AFRL) Rocket Propulsion Division (RQR). ASCENT delivers a 50% increase in density specific impulse over the present state-of-the-art hydrazine monopropellant. In addition to its performance advantages, ASCENT decreases handling hazards compared to hydrazine. ASCENT is an ionic liquid (IL) derived of hydroxylammonium nitrate (HAN), water, and other compounds to yield a low-toxicity and highly stable mixture of negligible vapor pressure.
We want to take a moment and share a number of public facts about the ASCENT propellant.
FACT: ASCENT Propellant Requires Fewer Personnel and Launch Vehicle Protections Than Hydrazine.
Did you know… ASCENT is characterized as a “Critical Hazard”, while Hydrazine is characterized as a “Catastrophic Hazard” per AFSPCMAN 91-710? This characterization permits ASCENT propulsion systems to employ roughly half the number of components of a similar hydrazine system. This increases reliability and reduces cost.
FACT: NASA’s Green Propellant Infusion Mission (GPIM) Was the First Use of ASCENT Propellant in Space.
Did you know… Plasma Processes LLC. build components for the GPIM Thrusters? Our El-Form Process makes near net shape refractory metal components for thrusters. The GPIM helped advance ASCENT range and launch vehicle acceptance and has made it easier for others to follow.
FACT: NASA’s Lunar Flashlight Mission Was the First Use of ASCENT Beyond Low Earth Orbit (LEO).
Did you know… Plasma Processes LLC. built and qualified the 0.1N Thrusters used on Lunar Flashlight? Four are in space now. Though it was launch on a Falcon 9 in December 2022, Lunar Flashlight was originally to launch on Artemis I, and had satisfied NASA payload safety requirements for launch on SLS.
FACT: ASCENT has 50% Greater Density Specific Impulse (Isp) than Hydrazine.
Did you know… ASCENT has 5% higher Isp and 46% higher density? That is comparable performance to traditional bipropellant thrusters. A hydrazine prop system could be swapped for a smaller ASCENT prop system, giving you more volume for other systems. Or you can go farther and longer with a similar sized system.
FACT: ASCENT Does Not Freeze…
Did you know… ASCENT has an ultra-low minimum storage temperature? There is no need for long-duration system thermal management, unlike hydrazine. Hydrazine has a similar freezing point to water, and space can be very cold. So you’d have to keep heaters on much of the time. With ASCENT, just let it get cold, and heat it when you need it. Save your power for other uses.
FACT: Small Satellites Using ASCENT Can Be Shipped Fueled from The Factory.
Did you know… ASCENT can be shipped cross country with your online shopping goods? ASCENT is classified as a 1.4C explosive (minor explosion hazard; largely confined to the package).
AF-M315E derives its low-toxicity-hazard characteristics and high mixture stability (even to very low temperatures) from the high solubility and negligible vapor pressure of all solution constituents, such that indefinite exposure to the open environment poses no safety issue. Ground operations are significantly reduced due to the decreased hazard of ASCENT. Hydrazine requires more significant crew training, size, and personal protective equipment. Also, hydrazine requires more complex transfer equipment for spacecraft loading.
Links:
https://www.nasa.gov/mission_pages/tdm/green/index.html