The QB50 project

Recent advances in rapid manufacture capabilities will allow the application to satellite structures.  Satellite structures made using rapid manufacture techniques may be made more cost effectively, be able to incorporate structural complexity previously impossible, allow physically complex optimised structures to be developed that reduce mass, reduce component count and increase functionality.

3D printing is a maturing technology. There has been a steady progression of increased resolution, increased speed of production, reduction of unit costs and a widening of material choices. Currently satellite structures are conventionally manufactured predominately using composite structures formed either through hand lay ups or manufactured by CNC techniques.  Regardless the structure configuration tends towards laminar plates with components and other structures attached by numerous secondary structures. By utilizing 3-D printing techniques with aerospace grade materials, load optimised structures with few joins and few parts can be manufactured allowing the production of low mass geometries currently not feasible. The application of this work would be applicable to other mass critical structural designs.

The processing speed, cost and flexibility requirements of future satellite-based applications cannot be satisfied with conventional radiation-hardened processors or custom integrated circuits. SRAM-based Field Programmable Gate Arrays (FPGAs) provide an opportunity for meeting these requirements with off-the-shelf hardware. The main challenge of using FPGAs for space applications is mitigating the effects of radiation-induced Single Event Upsets (SEUs).

The aim of the two projects supported in part by the Australian Research Council’s Linkage (LP140100328) and Discovery (DP150103866) Projects funding schemes is to develop key technology to enable off-theshelf hardware to be customized for this use without compromising reliability. The projects will develop the design methods needed to implement a given set of satellite applications on a processing platform composed of application-specific soft processors and accelerator circuits hosted on conventional reconfigurable logic devices. Crucially, the solution architecture will be sufficiently hardened against radiation-induced errors to meet reliability targets while satisfying performance and energy use constraints. During the course of these projects, these techniques will be demonstrated and tested in-orbit on the RUSH payload for the UNSW-EC0 CubeSat which is a part of the international QB50 CubeSat program funded by the European Union Framework project.

During 2015 a part-time research was identified and appointed in late 2015 on the LP140100328 project and a full-time researcher was identified and will take up his position early in 2016 on the DP150103866 project. Research work concentrated on the design and reliability aspects of the reconfiguration control network and its performance evaluation. In tandem with this, current research is looking at fault-tolerant reconfiguration network controller design. Research was also undertaken to reduce the overheads associated with using Dynamic Partial Reconfiguration (DPR) to overcome configuration memory errors in TMR systems.

In addition to these, considerable amount of activity has focused on the QB50 RUSH payload design and experiment. The payload board was designed and built while the firmware was developed. The payload supports two configurations, one looking at the efficacy of recovering from radiation-induced SEUs using our proposed modular recovery approach and another which uses the traditional scrubbing approach. The payload has been successfully integrated into the UNSW-EC0 CubeSat bus and has passed the thermal and vacuum environmental tests with flying colours. These will be followed by vibration tests in 2016 and subsequent shipment of the CubeSat for launch to Europe around June 2016.

Contact Dr Ediz Cetin and/or A/Prof Oliver Diessel for further information and research opportunities.

The Kea GPS Payload is a multi-experiment GPS hardware that is designed, built and tested by ACSER,UNSW and General Dynamics NZ. It is one of the first technology demonstration for a single-board GPS receiver that can host multiple experiments.Its customisability allows it to reconfigure itself to perform one of three experiment modes below:

Mode 1:  In-orbit Positioning

This is the main goal of this payload. It will exercise the standard navigation functionality of the Namuru GPS receiver when operating in low earth orbit, with the aim of validating the core receiver functionality and gaining flight heritage for the design. Results from ground-based satellite laser ranging on the spacecraft will also be performed will be used to validate the accuracy of the receiver.

Mode 2: GPS Radio occultation

The Kea GPS receiver listens to the transmissions from GPS satellites. Given their different orbits, the Earth will sometimes come between the two satellites, and its radio signal will have to pass through some of the Earth’s atmosphere before the planet blocks it out completely. The way that the signal fades in the atmosphere can be used to calculate the temperature and pressure along the line connecting the two spacecraft, providing a valuable new source of raw data for weather forecasting. 

Mode 3: GPS Reflectometry

The purpose of the reflectometry experiment is to use the Kea GPS receiver to perform remote sensing using GPS reflectometry. This involves observing GPS specular reflections from the earth’s surface using a custom Left-Hand Circularly Polarised antenna array that will be installed on the nadir face of the CubeSat. Observations from oceans under different sea-state conditions, preferably at locations at which observations from other independent instruments are available can be made, are desirable. Observations from land and perhaps sea-ice can also be made. The experiment data can be used to infer sea-state, wind speed, water-land boundaries and many other unexplored applications.