Mt Stromlo Summer Student Presentations 2016

This summer the Mount Stromlo Observatory hosted two undergraduate student programs that develop skills in astronomy, astrophysics and space engineering, and a broader understanding of the industry, the AITC Internship/Northrop Grumman Externship Program and the ANU Summer Scholars program.

ANU Summer Scholars

The Summer Scholars program gives undergraduate students an insight into what studying Honours or a postgraduate research degree is all about. Under the supervision of one of Stromlo’s eminent researchers, students complete an individual research project

AITC Internship/Northrop Grumman International Externship Program

The AITC Internship/Northrop Grumman Externship program gives undergraduate engineering students hands-on experience and helps train the industry professionals of the future. Students contribute to an active project under the supervision of AITC technical experts and industry specialists. Thanks to support from Northrop Grumman through their International Externship Program, this opportunity could be opened to students Australia wide. 

To celebrate the completion of these programs you are invited to attend the final presentations, meet the students and network with the experts that have supported them.  

 

12:00pm–12:10pm

Welcome

12:10pm–12:30pm

Ross Murray - “Quad Cell Alignment of Adaptive Optics Guide Star Laser Beam Transmitted Through Zerodur Mirror Optics”

As the world becomes ever more reliant on satellite technology, so it becomes increasingly important to safeguard the environment in which satellites operate.  Satellites are at risk of collisions with space debris and must make costly adjustments to their orbits to avoid being damaged.  Tracking the orbits of space debris allows for a satellite to be moved out of the collision path.

 

The high cost of changing a satellite’s orbit means satellite operators require very accurate predictions of potential debris collisions to warrant taking evasive action.  Compared to radar, laser tracking of debris offers highly accurate prediction of debris orbits. 

 

The ANU is developing an Adaptive Optics (AO) system to improve the performance of the EOS 1.8m laser tracking facility at Mount Stromlo.  The AO makes use of a Laser Guide Star (LGS) which is projected onto the sky through a Laser Launch Telescope (LLT).

 

Precise alignment of the Guide Star Laser beam on the LLT optics is important to reduce vignetting of the beam and maintain the LGS position. This project looks to control the beam position with a position sensing photodiode located behind the LLT secondary mirror.  99.5% of the laser beam is reflected and alignment of the laser will be done using the 0.5% that is transmitted through the Zerodur glass that forms the optic.

 

The proposal assumes homogenous scattering and reflection by the Zerodur and this research tests the reality of that assumption.  To determine the effect of the Zerodur on the beam alignment the experiment looks at the laser beam position after passing through various thicknesses of Zerodur and examines the effect of surface anomalies such as dust and scratches to establish the feasibility of this method of beam alignment.

12:30pm–12:50pm

Tom Dixon – “Investigating and Implementing Latency Characterisation Methods for Adaptive Optics Cameras”

Adaptive Optics are a series of optical techniques utilized to mitigate atmospheric distortion of telescope exposures by performing high-speed environmental measurements and applying pre or post correction to certain optical systems. As can be easily surmised, the latency of cameras in an AO system; the time between end-of-exposure and the corresponding data becoming available, is a critical parameter to be considered. However, this value is not one commonly published by camera manufacturers.

 

In this presentation, methodologies and preliminary results of two techniques are discussed. In one such methodology, pulses generated by an optical chopper are received by the camera. The duration and frequency of these pulses are controlled by manufacture of custom chopper wheels; the frequency (usually about one tenth of the camera sample rate) is altered to ensure that each pulse is distinct, and duration kept small (relative to exposure time) to allow the pulse to be timed to the end of exposure. Exposed frames are then retrieved through software and evaluated for delay, using a reference signal from the pulse generator that serves as a time stamp.

 

A simpler methodology is also proposed and discussed, wherin an LED is driven from a computer serial port and pulsed. The timestamp of the pulse command and frame retrieval are compared to allow the computation of latency. Due to the non-linear rise and fall times of the LEDs (characterised as part of this process), optimization of pulse length and intensity is performed to develop the most optimal signal-to-noise ratio.

 

Implementation issues and preliminary results are also discussed, although development is still ongoing; utilisation of these measurement techniques is not expected until later in the year.

12:50pm–1:10pm

Patrick Dawson - Mass transfer in close binary stars

Interacting binary stars lead to some of the most energetic phenomena in the universe, such as short gamma ray bursts, Type Ia and stripped core-collapse supernovae, X-ray bursts, and novae (which arise in cataclysmic variables, or CVs). These events have an important effect on the chemical evolution of galaxies, as they eject into the interstellar medium elements that would otherwise be locked up in the cores of stars. However, the evolutionary processes that these co-orbiting stars must pass through in order to end up with such an explosive fate are poorly-understood.

 

We can advance our understanding of how these systems form and evolve by comparing observed systems to simulated binaries computed with binary evolution models that sample a wide range of (orbital) parameters. The computer models enable us to predict what sorts evolutionary pathways are more or less frequent and what the final physical properties of the interacting binaries are.

 

This project involves a comparison of different evolutionary models from the binary population synthesis code ‘StarTrack’ with observational data on cataclysmic variables. The goal is to gauge how effectively the different models, which use different assumptions for unstable mass transfer, can explain the various kinds of novae and CVs that we observe. The project helps to inform any future changes to the models by identifying where the input physics can be most greatly improved, as well as advancing our understanding of close binary star evolution in general.

1:10pm–1:30pm

Break

1:30pm–1:50pm

Patrick Wain – Commissioning and Characterising a Mechanical Shock Test Facility

Mechanical shock testing is critical in characterising the performance and limits of engineering devices, structures and materials. Many applications require shock testing - from heavy-duty mining, agriculture, aerospace and defence-related equipment to small-size consumer products and micro-electronics. A high standard of testing is necessary in order to ensure the success of many projects and products.

 

A shock test facility is currently being commissioned at the Advanced Instrumentation and Technology Centre (AITC) to cater to the rapidly growing space, technology and innovation sectors, both locally and nationally. This will be capable of mechanical shock testing, which this project is concerned with, and pyroshock testing. The nature of these two environmental tests and differences between them will be discussed in this talk. The mechanical shock test environment will be capable of testing small specimens (<25kg), primarily through the use of an AVEX SM-105 Shock Test Machine. 

 

This eight week project focused on several stages of commissioning the AVEX SM-105 machine for use in testing. Examples of shock testing found in recent literature were used as case studies while investigating the feasibility of the project, along with the drafting of operational procedures and other test documentation. A brief assessment of the machine’s performance revealed that it was malfunctioning. Thus, an investigation into maintenance costs, procedures and options was done.

 

These actions are critical in bringing the machine, and facility, to test standard. The research conducted into uses of this shock machine and its role in AITC’s future work outlined the importance, capabilities and applications of the shock facility. Furthermore, how it relates to commercial, government and research interests.

1:50pm–2:10pm

Shani De Leeuw - Machine Learning and Data mining of the Skymapper Survey

Data from an all-sky survey may continue to be used by the scientific community decades after the survey is completed. The Australian National University (ANU) SkyMapper telescope is surveying the Southern sky in the optical spectrum. Simultaneously, the ASKAP/EMU survey  is to be completed within the next few years and will be the largest and deepest radio spectrum survey to date with an estimated 70 million sources. The long term goal of the research is to maximise the scientific knowledge that can be gained by combining data from the ASKAP/EMU and Skymapper surveys. As SkyMapper data is not yet available for the EMU pilot fields analysis was instead carried out using the VST/ATLAS survey which is functionally similar but covers the appropriate area of sky.

 

As it is difficult to directly cross-identify radio and optical sources mid-infrared data is often used as an intermediary step. High resolution infrared data is not available for the entire sky and as such the consequence of using the lower resolution data was examined. The effects of other properties such as radio and infrared flux on the chance of a match being found were also examined and will be discussed in detail.

 

It is possible to determine the redshift of a radio component once it has been cross-matched with an optical source. Spectra can be used to accurately measure redshift but the process is timely and expensive. Techniques have been developed to estimate redshift from photometric data. The accuracy of the redshift estimations for radio sources was compared to that of the overall population.

2:10pm–2:30pm

Aidan Kerr – Commissioning and Characterising a Mass Properties Test Facility

Mass Properties (centre of gravity, weight and moment of inertia) are inherent to all physical engineering products. The ability to measure these properties accurately is critical for most aerospace applications and can be useful for all fields of engineering as it provides a useful insight into how a device behaves when forces are applied.

 

The Mass Properties facility at the Advanced Instrumentation and Technology Centre (AITC) has the potential to accurately measure the centre of gravity, weight and moment of inertia for a wide range of devices under 25kg. These quantities will be measured using the “SE90168 Weight and Centre of Gravity” and the “XR Series Moment of Inertia” Instruments. These instruments will be available to use for any commercial, government or research purposes within the restrictions of the machines.

 

Over the next month and a half the project will focus on commissioning these machines and developing concise test procedures and documentation for use. These procedures are necessary for the safe operation of the instruments and will provide a foundation for all testing procedures of mass properties at the AITC.

2:30pm–2:50pm

Ryan Ridden-Harper - How did the weather on the early Earth control the recession of the Moon?

The origin of the Earth Moon system is usually understood to be the result of a colossal collision between two proto-planets. This model agrees with the isotopic ratios seen on the Earth and Moon, however, it predicts that the Moon was once very close to a fast spinning Earth.

 

The recession of the Moon can be explained by frictional tidal interactions on the Earth’s surface. Specifically, the friction between i) the tidal bulge raised by the Moon and ii) the Earth rotating underneath this tidal bulge - dragging the bulge out of alignment with the Moon-Earth axis. This friction speeds the Moon up in its orbit, causing it to recede while the Earth’s rotation is slowed (total angular momentum is conserved). The amount of friction between the bulge and the rest of the Earth depends on the viscosity of the bulge material, the depth of the ocean, the amount of continental shelf and even the weather.

 

Until recently, models of the Moon’s recession neglected to consider what effect the Earth’s atmosphere would have. As shown in Zahnle 2015 the atmosphere may have had a considerable impact upon the Moon’s recession, with a runaway greenhouse effect halting recession for 3 million years.

 

In this project the model used in Zahnle 2015 was examined and extended to be consistent with recent measurements of the Moon’s recession. This can provide an estimate of when the first continents formed and the tide heights four billion years ago at the beginning of life on Earth.

2:50pm–3:10pm

Break

3:10pm–3:30pm

Ali Haji Babaei – Characterisation of Attitude Determination and Control Systems for Cube Satellites

The introduction of commercially available off the shelf (COTS) standardised components for Cube Satellites have enabled miniaturised and cheaper access to space, increasing innovation and research in the space industry. Due to their compact size, there are compromises to consider when designing and configuring different components and payloads inside a standardised Cube Satellite.

 

For any mission that requires some form of manoeuvrability during space flight, Attitude Determination and Control Systems (ADCS) are a fundamental subsystem to consider. A comprehensive database and catalogue for ADCS solutions can prove useful for catering to the needs of a whole range of space missions as Cube Satellite applications become more prevalent, enabling designers to select the most appropriate ADCS for their application.

 

Information regarding ADCS components has been catalogued into a database which was then compared to a rubric outlining all possible design considerations. Different types, makes and models of Attitude Determination devices (sensors) and Attitude Control devices (actuators) are characterized and distinguished from one another as this project report explores the pros and cons of each subsystem choice.

 

Results from this report will be verified by performing a case study on the Australian Space Eye, a space telescope project employing a Cube Satellite. The case study outlines and justifies which combination of ADCS components is best suited to meet Space Eye requirements including all future work needed.

 

The report is intended to be a resource for those investigating the various merits of ADCS components for Cube Satellite design. In addition, this report will provide a foundation and tools for more Cube Satellite work to be completed and show how the ADCS database can be used to betterment any space mission requiring ADCS.

3:30pm–3:50pm

Diane Salim – Turbulence in Hickson Compact Groups

Star formation is inefficient, especially so in galaxies in Hickson Compact Groups (HCGs). HCGs, which are defined as small, relatively isolated systems of typically four or five galaxies in close proximity to each other, have been observed to contain galaxies which exhibit significant star formation (SF) suppression and are going through rapid morphological transformation. Suggestions regarding the cause of this SF inhibition include the injection of turbulence from collisions with the radio jets or AGN outflows, or with collisions and interactions within the group environment. In lieu of such speculations we present CO(1-0) observations from the Combined Array form Research in Millimeter Astronomy (CARMA) to trace the column density of molecular gas and 70 micron observations from the Herschel Space Observatory to trace the column density of star formation of 12 HCGs. We use these observations in the application of a universal star formation law to predict properties of turbulence within these HCGs galaxies

3:50pm–4:10pm

Justin Kruger – A survey and recommendation of CubeSat Attitude Determination and Control System test rigs for the Advanced Instrumentation and Technology Centre

The recent rise of the CubeSat nanosatellite has greatly expanded access to space, making it easier and cheaper to launch small payloads. As Australia’s only comprehensive space environmental test facility, the Advanced Instrumentation and Technology Centre (AITC) at Mount Stromlo is well-placed to take advantage of this growing industry. A desirable addition to AITC capabilities is hardware-in-the-loop testing of CubeSat attitude determination and control systems (ADCS); the ADCS is responsible for controlling satellite orientation during spaceflight and extensive testing is crucial during the design process. Hardware-in-the-loop techniques allow more realistic evaluations of such systems on the ground.

 

The AITC is a national test facility, and any recommended test rig must meet the needs of the broader space community. It must also test the Australian Space Eye, a CubeSat-format space telescope being supported by the AITC. The Space Eye introduces additional requirements due its large size and fine pointing control, acting as a driver and initial test case for the AITC rig.

 

The project surveyed recent ADCS test rigs from around the world to examine various designs, their performance and common testing needs, and the resulting catalogue provides a valuable overview of the state-of-the-art and methods used to achieve CubeSat simulation on the ground. Following this, strengths and weaknesses of each design were characterised with regards to AITC and Space Eye requirements. The most suitable design elements were combined into a recommended test rig configuration, optimally suited to AITC objectives whilst serving future needs of the small satellite industry.

 

The catalogue of ADCS test rigs will be presented, with examples of the analysis process for different systems and their comparisons to AITC requirements. Recommendations of design elements for the AITC rig will also be presented as an initial step of the design process.

4.10pm–4.30pm

Matthew Whitely – Platform stability for a balloon borne UV telescope

A long-duration high-altitude balloon flight provides access to short wavelength (100-200 nm) astronomical observations, and with a high cadence free from constant interference from cloud coverage. However, the available platform suffers significant motion of the payload that will requires stabilization to allow observations to take place. I will present an initial analysis of the available stability data, and the challenges involved in measuring a stability signal

5:00pm–6:00pm

AIAA Networking Event