CubeSat Propulsion and Maneuvering System
Propulsion
CubeSat Propulsion and Maneuvering System (MSC-TOPS-155)
Flight qualified components minimize cost and schedule, maximize performance
Overview
NASA Johnson Space Center’s R5 Project Team has developed a modular CubeSat platform series, called “R5-SX”, whose six-degree-of-freedom cold-gas propulsion and maneuvering system employs three mainstay innovations: a High-Pressure Manifold, a Thruster Pod, and Threaded Jet Inserts. Their technical descriptions can be found below.
The SX-series platform was developed to significantly reduce costs associated with payload demonstration in Low Earth Orbit (LEO) by implementing a minimally-viable product approach to component scope definition without sacrificing performance. Although aligned with on-orbit mission abilities, these individual propulsion and maneuvering innovations may also translate to terrestrial applications that utilize, or desire, metered pressurized fluid-flow.
The High-Pressure Manifold, Thruster Pod, and Threaded Jet Inserts are at technology readiness level (TRL) 8 (actual system completed and "flight qualified" through test and demonstration). Please note that NASA does not manufacture products itself for commercial sale.
SHOWN ABOVE: The R5 Spacecraft 2, (R5-S2), and the R5 Spacecraft 4, (R5-S4), are the first two R5 spacecraft to successfully make it into orbit. These spacecraft, which contain no space-rated components, quickly exceeded their minimum mission success criteria and operated throughout their 10-month mission lifetime in orbit.
The Technology
Starting with a "clean sheet" for process and system design, the R5 Project Team charted a path, subsystem by subsystem, through commercial, industrial, automotive, and medical-grade components, to arrive at a functional baseline CubeSat (SX-series) bus. Although the R5 approach leans heavily on commercial-off-the-shelf (COTS) hardware, there are instances where NASA custom-designed components have been determined to be the less expensive and faster-to-develop option. Such is the case for the SX cold-gas propulsion and maneuvering system’s High-Pressure Manifold, Thruster Pod, and Threaded Jet Inserts.
The High-Pressure Manifold (MSC-27997-1) is a ported fluid distribution manifold that, relative to the SX-series CubeSat, distributes pressurized cold-gas to each Thruster Pod. Machined from high-grade aluminum, the SX-series manifold has a Maximum Design Pressure (MDP) of 3000 psig. The R5 team designed the manifold to accept a fuel tank, regulator, isolation valve, relief valve, transducer, and other COTS high-pressure fittings.
There are four component Thruster Pods (MSC-27996-1) per each SX-series CubeSat, and each Thruster Pod is fed pressurized cold-gas from the High-Pressure Manifold. These pods are designed to be 3D-printed using additively-manufactured aluminum and are later machined to add female threads for the Threaded Jet Inserts, heli-coils, and valve ports. Each pod comprises three integrated propellant conduits that independently feed the Threaded Jet Inserts. Each directional jet has an assigned thruster valve, mounted to the Thruster Pod, which throttles the pressurized cold-gas for CubeSat propulsion and maneuvering about three linear and three rotational axes.
Finally, the Threaded Jet Insert (MSC-27994-1) embodies a set-screw form factor, and relative to the SX-series CubeSat, threads into the outward-facing end of each Thruster Pod propellant conduit. Each jet is laser machined and employs an internal flow-through micro-nozzle to accelerate escaping gas fed from the thruster valve to produce thrust.
These SX-series propulsion system innovations for R5 CubeSats may also have terrestrial applications across multiple industries where, for example, targeted high-velocity gas bursts, precise pneumatic micro-force, or modular choked-flow gas metering are required.
Benefits
- Flight-qualified technology
- Tunable architecture yields pressure/flow metering applications across multiple industries
- Components together facilitate a six degree-of-freedom cold-gas propulsion and maneuvering system
- High-Pressure Manifold features 3000 psig maximum design pressure and accommodates COTS subcomponents
- 3D-printed Thruster Pod comprises three-axis thruster ports for thrust metering via the Threaded Jet Inserts
- Threaded Jet Insert features a set-screw form-factor with a tunable internal micro-nozzle
- Intended component shirt-sleeve build environment minimizes schedule duration and dependency for LEO demonstration
- Components facilitate quick-to-flight CubeSat builds for responsive payloads
- Features minimal approach philosophy to speed assembly and integration
Applications
- System Aerospace: CubeSat propulsion and maneuvering for payload demonstrations; servicing and inspection of vehicles in LEO; commercial satellite life-extension platforms; active space debris removal tugs
- System Terrestrial: air-bearing orbital simulation testbeds; pneumatic actuation in spark-hazardous environments; UAV loss-of-control and emergency recovery
- High-Pressure Manifold Terrestrial: alternative fuel system distribution block such as hydrogen fuel cell or CNG; rapid inflatables and life support, high-pressure emergency gas deployment
- Thruster Pod Terrestrial: UAV and drone stabilization, cold-gas reaction control system; industrial automation and soft robotics; automated pneumatic sorting systems
- Threaded Jet Insert Terrestrial: Semiconductor and optics manufacturing, micro-jet gas bursts for cleaning; Precision metering and spray coating, quick-swap metering orifices for lab gas-calibration equipment, atomization nozzles
Technology Details
Propulsion
MSC-TOPS-155
MSC-27994-1
Patent Pending
Similar Results
Miniature Separable Fill & Drain Valve
The Miniature Separable Fill & Drain Valve consists of two halves (ground and flight). The flight half is attached to the vehicle (i.e., CubeSat), and the ground half can be inserted into the vehicle in the same port as the flight half, connecting the two halves together. In normal state, the flight half seals the flow path. When the ground half is connected, the flow path is opened, allowing connected ground support equipment to supply fluid through the valve. The valve is manually operated.
There are redundant seals to eliminate leakage around the valve, including NASA's previously-patented Low-Cost, Long Lasting Valve Seal design (Patent No. 10,197,165; see MFS-TOPS-71 in the Links section of this flyer for more information) on the flight half. This eliminates the need for a swaged assembly process and the additional hardware and equipment that are typically required in conventional, elastomeric valve seat installations. The design also includes a cap for the flight half to ensure there is no leakage in flight configuration.
The Miniature Separable Fill & Drain Valve has been prototyped and provides valuable benefits for CubeSat applications. The valve could also have applications in the industrial processing industry where low flow devices are commonly used. The design is also scalable to larger applications where the removal of the actuation device would be desired.
Cost Optimized Test of Spacecraft Avionics and Technologies(COTSAT) Modular Spacecraft Software Architecture
The goal of COTSAT as a technology demonstration unit is to demonstrate the ability for drastic cost reduction in spacecraft design and to develop methods and technologies for maximizing reuse of developed spacecraft hardware, software and related technology on future missions. This approach will enable for rapid response capabilities given advances in rapid prototyping.
COTSAT consists of the following sub-systems:
- An artificial environment container, which comprises much of the satellite structure, is used to contain the single atmosphere environment. The artificial atmosphere container is used to replicate an Earth-like atmosphere, allowing the use of Commercial-Off-The Shelf (COTS) hardware and electronics which were not necessarily originally designed to operate in the vacuum environment of space.
- A key design element in the bus structure of COTSAT is the modular platform upon which the bus is assembled. This structure allows for a logic-flow integration of components leading to ideal placement of electronics.
- The Electrical Power System (EPS) architecture utilizes a distributed power and self-monitor approach.
- The Command and Data Handling (C&DH) subsystem provides a number of critical capabilities, including spacecraft health and status monitoring, communication, payload science data management and subsystem management.
- The COTSAT communications architecture incorporates four independent communications paths.
- The software architecture consists of modular, independent software daemons for each subsystem or capability such as the star tracker, the Inertial Measurement Unit (IMU), the reaction wheels, the main executive, the communications system, the control system and the payload.
- The COTSAT has a three-axis Attitude Determination And Control System (ADACS), using four reaction wheels and three magnetic torque coils.
- To aid in technology development and testing, the COTSAT hardware and technology performance has been verified by a number of prototype test-beds. There have been three major test platforms during the development cycle.
Multi-Link Spherical Joint
The Multi-Link Spherical Joint developed at NASA Johnson Space Center provides a substantial improvement over typical joints in which only two linearly actuated links move independently from one another. It was determined that the rotation point of a trussed link needed to be collocated at a shared point in space for maximum articulation. If not allowed separate rotation, the line of action through a universal joint and hinge acts effectively as another linkage. This leads to a much more complex and uncontrollable structure, especially when considering multiple dimensions.
Comprising the Multi-Link Spherical Joint, a spherical shell encases the cupped ends of each six possible attachments and allows each of those attachments to be independently controlled and rotated without inhibiting the motion of the others. To do this, each link is precisely limited to 15 degrees of rotation off the link centerline, thus allowing a total of 30 degrees of rotation for each link. The shell-and-cup structure can handle the loads of linear actuators that may be used to control and vary the geometry of a truss system utilizing the new joint technology. The calculated operating load that the truss system must handle can be used to scale the size of the joint, further allowing customization of any potential truss system. Additionally, the incorporated linear actuators can be controlled and powered by wiring routed through the joint without putting undo stress on the wires during operation. Accordingly, this innovative joint technology enables more efficient deployment and precise operation of articulating structures.
The Multi-Link Spherical Joint is at technology readiness level (TRL) 4 (component and/or breadboard validation in laboratory environment) and is available for patent licensing. Please note that NASA does not manufacture products itself for commercial sale.
High Propellant Throughput Small Spacecraft Electric Propulsion Thruster
NASAs High Propellant Throughput Small Spacecraft Electric Propulsion thruster offers a propellant throughput capability of greater than 120 kg with a nominal thruster efficiency greater than 50%. The new thruster design combines heritage Hall thruster component design approaches with recent NASA GRC advancements in the areas of advanced magnetic circuit design, robust propellant manifolds, and center mounted cathodes. Prototypes of the High Propellant Throughput Small Spacecraft Electric Propulsion thruster have been fabricated and proof-of-concept has been demonstrated.
A significant advancement in the High Propellant Throughput Small Spacecraft Electric Propulsion thruster is NASA's optimized magnetically shielded (OMS) field topology. The new OMS configuration reduces discharge channel erosion rates compared to conventional Hall thrusters, while reducing front pole cover erosion rates compared to traditional magnetically shielded Hall thrusters. This system also includes a largely unibody structure to reduce fabrication cost, increase strength, and optimize thermal management. A coupling plate between the high voltage discharge channel and low voltage thruster body allows more efficient thruster assembly and verification processes. Other design advancements further simplify assembly, improve robustness, and optimize performance.
Nanosatellite Launch Adapter System
NLAS consists of three configurable subsystems to meet the needs of a multi-spacecraft launch. The Adapter is the primary structure that provides volume for secondary payloads between the rocket and the primary spacecraft. The Adapter takes advantage of the frequently unused volume within the rocket fairing. It fits up to 4 NLAS Dispenser units, or 8 eight Poly-PicoSatellite Orbital Deployers (P-PODs), or any combination thereof. The NLAS Dispenser is reconfigurable to support either two 3U bays or a single 6U bay and is compatible with 1U, 1.5U, 2U, 3U, and 6U satellites. The Dispenser system is the first 6U deployment system backwards compatible to 3U spacecraft. Finally, the NLAS deployment Sequencer is an internally powered subsystem which accepts an initiation signal from the launch vehicle and manages the actuations for each deployment device per a user programmable time sequence. It is programmed using ground support equipment (GSE) and a simple graphical user interface (GUI) on a computer.
