Electrically controlled ASCENT propellant loading and offloading PGSE for responsive space missions

Flight Works is proposing to apply its expertise in pump-fed, low-pressure ASCENT propulsion systems and that of its principals having interacted with government ranges and commercial spaceports to develop an ASCENT propellant loading and offloading PGSE (Propulsion Ground Support Equipment) for use in responsive missions. The Phase I scope includes the demonstration of ASCENT transfer using the prototype pump of the PGSE, capable of loading/offloading 200 kg of ASCENT in less than 2 hrs. ASCENT is a “green” propellant which offers 40% greater density-Isp than hydrazine. One of its key characteristics is a very low vapor pressure which not only lends it well to handling in open containers, but also enables its use in pump-fed systems without needing to pressurize containers or tanks. ASCENT was first demonstrated on the NASA Green Propellant Infusion Mission (GPIM) in 2019; this included the first range propellant operations using an AFRL loading system. The second spacecraft featuring ASCENT was NASA’s Lunar Flashlight in 2022. Its 3U propulsion system was loaded at NASA MSFC and then shipped to Cape Canaveral for launch. It incorporated a Flight Works pump which provided high-pressure ASCENT to the thrusters. Flight Works is now working on ESPA- and ESPA-GRANDE class pump-fed ASCENT propulsion systems for NASA and AFRL. Some of these systems incorporate the ability to refuel the spacecraft, with the system being able to operate either as a refueler or as a client. The proposed ASCENT PGSE has an architecture similar to that of those systems, with the addition of key functions and features needed for responsive ground operations at a range: Compliance with SSCMAN91-710 requirements Materials compatible with ASCENT, includes attempting to totally eliminate 400-Series stainless steels Low-pressure pump-fed system to further decrease hazards (no containers/tanks at high-pressure) Electronic operations controlled either locally at the PGSE or remotely Built-in vacuum and purge capability Capable of loading/offloading 200 kg of propellant in less than 2 hrs. Built-in offloading capability with the use of a bidirectional electric pump without need for spacecraft tank pressure Able to pressurize the client at some low pressure, either adequate for pump-fed systems (typically < 30 psig), or to apply a blanket pressure to the tank(s) prior to full pressurization later in the CONOPS. In addition to the transfer tests to be conducted with ASCENT under Phase I, the effort also focuses on developing a business plan to commercialize the PGSE for use at ranges, at ASCENT test operators, and at spacecraft manufacturer sites.