Barry Nakazono's research while affiliated with California Institute of Technology and other places

... Hybrid propulsion technology using Mixed Oxides of Nitrogen (MON-25) with SP7 paraffin-based fuel was matured, The final decision to select solid propulsion over hybrid was made due to its higher TRL. However, the advantages of hybrid propulsion included its performance, reignitability (thus single stage MAV design unlike using SRMs) and storability at low temperatures (for MON-base propellants) [76]. Hybrid rocket propulsion has been even proposed for missions to outer planets of our Solar System [77]. ...

... Hybrid propulsion has been proposed and studied for the emerging smallsat and cubesat market, boasting higher ISP values and denser fuel, allowing these satellites to successfully achieve required ΔV values and perform orbital insertion maneuvers [1]. Most recently, a hybrid design competed against a solid rocket booster as a viable option for the upcoming Mars Ascent Vehicle (MAV) mission, demonstrating improved fuel performance on a Martian surface and the ability to restart its motor [2]. However, conventional propulsion system heritage overshadows hybrid rocket consideration for many of these applications -NASA greenlit the solid rocket booster MAV design as solid propulsion technology already operates at a higher technological readiness level (TRL) and has been used successfully in space missions in the past. ...

... A preliminary review was held by Marshall Space Flight Center (MSFC) Advanced Concepts Office, see reference [5]. That study led to a larger vehicle study, called a Preliminary Architecture Assessment (PAA), between a two stage to orbit solid [6,7] and the single stage hybrid [8,9] propulsion systems. A down selection between the solid and hybrid concepts occurred in December of 2019. ...

... JPL is working on a hybrid propellant thruster designed for CubeSats that could be accommodated within a 12 U envelope, capable of delivering a ∆v of over 200 m/s to a 25 kg spacecraft [14]. The 40 N thruster uses a GOX/PMMA propellant mix and an augmented GOX/methane spark igniter and has demonstrated successful vacuum condition tests with multiple reignitions, achieving over 300 s of specific impulse [15]. NASA Ames has conducted many tests on their 25 N hybrid for small spacecraft, a project that spanned several years [16]. ...

... Since the maiden flight of SpaceShipOne, hybrid rockets have become the core technology of at least seven Earth-launch vehicle developers: Rocket Crafters/Vaya Space (since 2010, USA [5,6]), Gilmour Space Technologies (since 2012, Australia [7,8]), TiSPACE (since 2016, Taiwan [9,10]), Nammo (Nucleus project since 2017 [8,11]), HyImpulse (since 2018, Germany [12,13]), Firehawk (since 2018, USA [5,14]), and SpaceForest (SIR project since 2018, Poland [15,16]); at least four new satellite thruster developers: T4i (since 2014, Italy [17]), Utah State University (since 2014, USA [18,19]), NASA (Kick Motor project since 2016, USA [20,21]), and Hokkaido University (Kick Motor project since 2017, Japan [22,23]); and at least one planetary ascent vehicle developer: NASA (MAV project since 2016, USA [24,25]). In recent years, the Hokkaido University kick motor has become the focus for the authors' work. ...

... interplanetary exploration missions [1][2][3][4][5]. Despite interest from the aerospace sector, the maturation of hybrid rocket technology has been hindered by significant obstacles, a crucial one of which is sub-optimal combustion performance from low-regression-rate, polymer-based fuels [6,7]. ...

... In fire science, PMMA has recently been used as a baseline solid fuel to study flame spread in both normal [10] and reduced [11] gravity, with applications to material flammability for in-space missions. In propulsion, the stability of PMMA in long-term storage has motivated its investigation as both a hybrid rocket propellant [7,12] and for solid-fuel scramjet applications [13]. In both applications, knowledge of PMMA's regression rate -which is influenced heavily by local radiant heat flux and flow conditions -is critical to device safety, performance, and mission lifetime. ...

... CubeSats are already under development or evaluation for interplanetary missions (Staehle et al. 2013;Schoolcraft et al. 2017;Jens et al. 2018;Benedetti et al. 2019;Cappelletti et al. 2020), and their viability for advancing our knowledge of astrobiology appears promising (Elsaesser et al. 2020;Robson & Cappelletti 2022;Calabria et al. 2023;Massaro Tieze et al. 2023). Let us consider a typical 1U CubeSat with a mass of M ls ≈ 1 kg, and suppose that N ls ≈ 1000 of them are launched toward an ocean world (e.g., Enceladus). ...

... 69 Many hypergolic ignition studies have been then carried out by Purdue and Penn State universities which drop tested different additives with mixed oxides of nitrogen (MON), being MON30 the envisaged MAV oxidizer. 70 The best options, based on ignition delay criteria, have been also firing tested, in combination with SP7, by Purdue University, which also performed several SP7 firing tests (with MON3 instead of MON30) into an optically accessible quartz sub-scale combustion chamber. An intensive sub-scale test campaign has been also performed by SPG, which completed 32 and 8 successful firings with N 2 O and MON3, respectively. ...

... We consider two different orbits for our orbiter, and compare their relative performance. We first consider the orbit of the VAMOS orbiter concept [60,42], a circular, equatorial orbit with an altitude of 30,000 km. This orbit has a full view of half the planet at any given time, and a long orbital period of 20.91 hours. ...