GPIM AF-M315E Propulsion System
The NASA Space Technology mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) Technology Demonstration Mission (TDM) will demonstrate an operational AF-M315E green propellant propulsion system. Aerojet-Rocketdyne is responsible for the development of the propulsion system payload. This paper statuses the propulsion system module development, including thruster design and system design; Initial test results for the 1N engineering model thruster are presented. The culmination of this program will be high-performance, green AF-M315E propulsion system technology at TRL 7+, with components demonstrated to TRL 9, ready for direct infusion to a wide range of applications for the space user community.
Green Propulsion Advancement: Challenging the Maturity of Monopropellant Hydrazine
Recent commercial and government investments have resulted in substantial advances in the technology readiness of a number of new candidate “green” monopropellants, many of which have already completed, or will complete in the next few years, successful on-orbit demonstrations. These propellants are often touted as potential (and in some cases technology-level ready) replacements for conventional hydrazine. This paper presents a comprehensive, carefully considered set of screening criteria, against which will be evaluated a number of these emergent candidates alongside flight-proven propellants. Thereafter, a thorough assessment of both the performance advantages and disadvantages, as well as current states of the art (and technology readiness levels) for a number of these emerging green technologies as compared with each other and incumbent hydrazine flight systems are provided. Additional discussion is included addressing what it notionally means for a propellant to be green, how definitions vary throug...
STP-SIV and ORS ISET spacecraft-to-payload interface standards
Spacecraft standards can enable dramatic reduction in the cost, schedule, and risk of spaceflight. After the first build of a standard spacecraft the non-recurring engineering is complete which allows rapid, cost-effective production of subsequent units. Spacecraft standards can increase the supplier base by encouraging multiple organizations to build components, subsystems, or spacecraft according to the same standard. Interface standards promote rapid and low-risk integration. The Space Development and Test Wing (SDTW) of the Space and Missile Systems Center (SMC); and the Naval Research Laboratory (NRL), Applied Physics Laboratory (APL), and a consortium of aerospace industry and academia partners have developed standards for two independent projects with different, yet synergistic goals. SDTW leads the Space Test Program-Standard Interface Vehicle (STP-SIV) program with prime contractor Ball Aerospace & Technologies Corp (Ball Aerospace). STP-SIV is a small spacecraft bus with well-defined and documented standard interfaces to the payload, ground, and launch vehicle (LV). STP-SIV is designed to provide low cost space access to the science and technology (S&T) community. NRL leads the Operationally Responsive Space (ORS) standard bus development. The ORS bus standards were developed by the Integrated System Engineering Team (ISET) consisting of technical experts from over a dozen government and industry partners, chartered with generating standards for production of responsive spacecraft buses for the ORS Program Office. Both programs provide to the space community well-defined standard spacecraft (SC) to payload (PL) interfaces on which to base future PL designs. Rather than designing a unique SC for each payload; the standards provide adaptable interfaces to accommodate a range of payloads. STP-SIV offers a Payload User's Guide (PLUG) which defines the mechanical, thermal, power and data interfaces to help facilitate PL design and integration. Similarly, the ISET developed a Payload Developers Guide (PDG) describing capabilities and interface requirements for the ORS standard. Ball Aerospace has been contracted to standardize the ORS PDG such that the payload interface information and document organization follow the same outline and similar content as the STP-SIV PLUG. The complementary documents, including a payload questionnaire, along with a merged “flysheet” table containing summary-level capabilities of each platform will aid payload providers in selecting the appropriate spacecraft platform to host their payloads. This paper focuses on standard payload hosting capabilities, described in STP-SIV PLUG and ORS PDG, and the benefits of standardization of these small space vehicle platforms to the S&T, ORS, and other aerospace communities.