Cyber-Physical Systems

Space is attracting ever growing interest for a wide range of applications including near-Earth commercial satellites, human flights for space transport/tourism, and interplanetary scientific missions.  Economical and reliable space transport plays a key role for successful space development and exploration globally.  The Space Transport and Smart Satellites (STSS) team conducts research to realise next-generation commercial space technologies, focussing on the following key areas:

• Reusable space transportation systems;
• Micro-satellite systems deployment and operations;
• Space Traffic Management (STM) systems design and operations;
• Contributions to the SmartSat Cooperative Research Centre (CRC).

Reusable Space Transportation Systems

Rocket-based combined cycle (RBCC) propulsion integrating rocket, ramjet and scramjet engines enables continuous operation and efficient transport from ground to space. Reliable mode transition between engine modes is essential for successful RBCC operation.

Turbine-based combined cycle (TBCC) propulsion integrating turbojet, ramjet and rocket engines also offers promise for economically viable future space transport. Pre-coolers to reduce airflow temperature drastically are the key component for TBCC.

Airbreathing propulsion technologies will play a pivotal role to in realising of future space launch systems by replacing present costly rocket launch.  Two-stage-two-orbit (TSTO) system comprising RBCC-powered booster and rocket-powered orbiter is expected to enable reusable launch vehicles, but inherently highly complex due to multi-mode engine operation. RBCC-Powered TSTO has been developed under joint research agreement between RMIT and JAXA (Japan Aerospace Exploration Agency) entitled “Cooperative research on the application of advanced optimisation techniques to the design of future transportation systems”.

Micro-Satellite Systems Deployment and Operations

Effective spacecraft deployment is in increasing demand in recent space development with the emergence of micro satellites and small launchers for both scientific and commercial applications.  In our research, we have performed MDO studies addressing: 

·        Co-planar deployment multiple satellites via double Hohmann transfers to phasing orbit and returning to reference orbit; 

·        Propellant-less multi-plane constellation formation exploiting nodal precession from J2 perturbations following deployment by RBCC-powered TSTO.

This allows achieving multiple objectives such as fuel, flight time, and radiation simultaneously.

Electric Propulsion

Ion thrusters enable highly effective space propulsion, offering a very large specific impulse albeit very small thrust.  They are suitable for applications such as interplanetary and interstellar missions as well as station keeping of spacecraft.

·       Cusped field thrusters (CFTs) are an electrostatic propulsion technology that uses permanent periodic magnets for plasma confinement and acceleration.  They feature high efficiency and long operational lifetime.

·       Downscaling would be needed to use CFTs for micro-satellite platforms but may be limited by the sensitivity of CFT performance to thruster size.

MDO techniques developed at RMIT have been highly instrumental in CFT downscaling.

Space Mission System Design

The group supports various academic activities including RASC-AL (Revolutionary Aerospace Systems Concepts – Academic Linkage Competition), which is a university-level space design competition for students sponsored by NASA.

·       Teams develop new concepts and full-scale mission architectures that support NASA’s goal of extending humanity’s reach into space.

·        RMIT participated in 2016, 2017 and 2018 RASC-AL with international partners (invited to final round in Florida for both years).

Space Traffic Management Systems

CPS group also performs research on Space Traffic Management (STM) systems for safe and unsegregated space transport operations. Progress in spaceflight research has led to the introduction of various manned and unmanned reusable space vehicle concepts, opening up uncharted opportunities for the newborn space transport industry. For future space transport operations to be technically and commercially viable, it is critical that an acceptable level of safety is provided, requiring the development of novel mission planning and decision support tools that utilize advanced Communication, Navigation and Surveillance (CNS) technologies, and allowing a seamless integration of space operations in the current Air Traffic Management (ATM) network. Key areas of research concentration include:

·        Emerging (“new-entrant”) platform operational concepts and capabilities, highlighting both the challenges and the opportunities brought in by the integration with conventional atmospheric air transport.

·        Common launch and re-entry planning methodologies, where the physical and computational limitations of these approaches are identified and applicability to future commercial space transport operations are assessed.

·        On-orbit phase, where the unique hazards of the space environment are examined, towards identifying the necessary elements required for space object de-confliction and collision avoidance modelling.

·        Regulatory framework evolutions required for spacecraft operations with a focus on space debris mitigation strategies and operational risk assessment.

·        Atmospheric flight phases, where possible extensions and alternatives to the conventional airspace segregation approaches are investigated, including promising Air Traffic Flow Management (ATFM) and Dynamic Airspace Management (DAM) techniques, to facilitate the integration of new-entrant platforms.

·        Advanced modelling approaches to meet on-orbit risk criteria and evolutionary requirements to improve current operational procedures.

Insights gained from this research will inform the future development of CNS/ATM and Avionics (CNS+A) systems and associated cyber-physical architectures for Space Traffic Management (STM).

SmartSat Cooperative Reserach Centre Contributions

As part of the RMIT University contributions to the SmartSat Cooperative Research Centre (CRC), the CPS Group is leading the research efforts in the following key area:

·         Intelligent Satellite Systems. Development of next generation systems to enable intelligent behaviour and autonomous decision making/operations of satellites and satellite constellations (artificial intelligence and machine learning software solutions). Novel systems for detection and characterisation of threats from Resident Space Objects (RSO) including autonomous capability and Space Traffic Management;

·         Advanced Communications, Connectivity and Internet of Things (IoT) Technologies. Development of algorithms and technologies for laser communication links with high data transfer rates. Development of adaptive intelligent radio technology allowing sensing and flexible use of spectrum. Development of systems that allow seamless connectivity between satellite and terrestrial communications;

·         Next Generation Earth Observation Services. Development and delivery of industry specific EO sensors (e.g., smart LiDAR and passive IR technologies) and data analytics services for multiple applications, including: Agriculture, Mining/Resources, Transport and Logistics.