Energy efficiency studies for dual-grating dielectric laser-driven accelerators

Dielectric laser-driven accelerators (DLAs) can provide high accelerating gradients in the GV/m range due to their having higher breakdown thresholds than metals, which opens the way for the miniaturization of the next generation of particle accelerator facilities. Two kinds of scheme, the addition of a Bragg reflector and the use of pulse-front-tilted (PFT) laser illumination, have been studied separately to improve the energy efficiency for dual-grating DLAs. The Bragg reflector enhances the accelerating gradient of the structure, while the PFT increases the effective interaction length. In this paper, we investigate numerically the advantages of using the two schemes in conjunction. Our calculations show that, for a 100-period structure with a period of 2 micrometer, such a design effectively increases the energy gain by more than 100 % when compared to employing the Bragg reflector with a normal laser, and by about 50 % when using standard structures with a PFT laser. A total energy gain of as much as 2.6 MeV can be obtained for a PFT laser beam when illuminating a 2000-period dual-grating structure with a Bragg reflector.Comment: 7 pages, 4 Figures, Proceedings of EAAC2017 Conferenc

First comparative field test of pressurised rover prototypes

The conceptual designs, interior layouts and operational performances of three pressurised rover prototypes - Aonia, Ares and Everest - were field tested during a recent simulation at the Mars Desert Research Station in Utah. A human factors experiment, in which the same crew of three executed the same simulated science mission in each of the three vehicles, yielded comparative data on the capacity of each vehicle to safely and comfortably carry explorers away from the main base, enter and exit the vehicle in spacesuits, perform science tasks in the field, and manage geological and biological samples. As well as offering recommendations for design improvements for specific vehicles, the results suggest that a conventional SUV would not be suitable for analog field work; that a pressurised docking tunnel to the main habitat is desirable; that better provisions for spacesuit don/doffing and storage are required; and that a crew consisting of one driver/navigator and two field science crew specialists may be optimal. From a field operations viewpoint, a recurring conflict between rover and habitat crews at the time of return to the habitat was observed. An analysis of these incidents leads to proposed refinements of operational protocols, specific crew training for rover returns and again points to the need for a pressurised docking tunnel. A 'leap-frog' incremental development methodology aimed at producing ever higher fidelity rover analogs is advocated

Field testing Marsobot, a Mars society Australia robotics project

This paper introduces Mars Society Australia’s Marsobot project, and describes the performance of robots during engineering testing at Arkaroola, South Australia. Two teleoperated rovers, one four-wheeled (Little Blue) and a larger eight wheeled machine (Miner), have been built using off the shelf components as part of the project in order to characterise strengths and limitations of different size machines. Both rovers underwent standardised DHS-NIST-ASTM tests over the period 5 – 12 July, 2014. The tests were conducted in controlled conditions and were designed to provide useful engineering data on the rovers’ range and mobility, as well as highlight potential flaws and limitations in design. Both Little Blue and the Miner performed well in the tests, though specific limitations in design robustness and endurance were observed. Lessons learned from these tests will be incorporated into future improvements of the rovers, and refining of the Marsobot project overall

Jarntimarra-1: Selecting an Australian Mars analogue research site

No abstract availabl

Surveying for Mars analogue research sites in the central Australian deserts

In anticipation of a future crewed mission to Mars, the international non-profit organisation known as the Mars Society is currently establishing four mockup bases at which planetary surface operations simulations, equipment testing and personnel training exercises will be conducted over the next decade. These should provide valuable design data for, and raise public awareness about, plans to explore the red planet. One of these bases, which are organised around a habitat of the kind that is likely to serve as shelter for surface-dwelling astronauts, is to be sited in central Australia under the name MARS-OZ. To find a suitable location, the Mars Society Australia has conducted a ground-truth survey of 15 potential sites as practical scientific analogues of the Martian surface, recording these in a specialised database. Each site was assessed on a set of geomorphic, science/engineering, logistic and visual analogue criteria. Six circular exploration zones 200 km in diameter were identified as clusters of the most significant, observed, comparative planetological features. These zones were then ranked to recommend a series of 'landing sites', at which future field seasons of exploratory science may be conducted

Comparative field tests of pressurised rover prototypes

The conceptual designs, interior layouts and operational performances of three pressurised rover prototypes - Aonia, ARES and Everest - were field tested during a recent simulation at the Mars Desert Reserch Station in Utah. A human factors experiment, in which the same crew of three executed the same simulated science mission in each of the three vehicles, yielded comparative data on the capacity of each vehicle to safely and comfortably carry explorers away from the main base, enter and exit the vehicle in spacesuit, perform science tasks in the field, and manage geological and biological samples. As well as offering recommendations for design improvements for specific vehicles, the results suggest that a conventional Sports Utility Vehicle (SUV) would not be suitable for analog field work; that a pressurised docking tunnel to the main habitat is essential; that better provisions for spacesuit storage are required; and that a crew consisting of one driver/navigator and two field science crew specialists may be optimal. From a field operations viewpoint, a recurring conflict between rover and habitat crews at the time of return to the habitat was observed. An analysis of these incidents leads to proposed refinements of operational protocols, specific crew training for rover returns and again points to the need for a pressurised docking tunnel. Sound field testing, circulating of results, and building the lessons learned into new vehicles is advocated as a way of producing ever-higher fidelity rover analogues

Comparative field test of pressured rover prototypes

The conceptual designs, interior layouts and operational performances of three pressurised rover prototypes - Aonia, ARES and Everest - were field tested during a recent simulation at the Mars Desert Research Station in Utah. A human factors experiment, in which the same crew of three executed the same simulated science mission in each of the three vehicles, yielded comparative data on the capacity of each vehicle to safely and comfortably carry explorers away from the main base, enter and exit the vehicle in spacesuits, perform science tasks in the field, and manage geological and biological samples. As well as offering recommendations for design improvements for specific vehicles, the results suggest that a conventional Sports Utility Vehicle (SUV) would not be suitable for analog field work; that a pressurised docking tunnel to the main habitat is essential; that better provisions for spacesuit storage are required; and that a crew consisting of one driver/navigator and two field science crew specialists may be optimal. From a field operations viewpoint, a recurring conflict between rover and habitat crews at the time of return to the habitat was observed. An analysis of these incidents leads to proposed refinements of operational protocols, specific crew training for rover returns and again points to the need for a pressurised docking tunnel. Sound field testing, circulating of results, and building the lessons learned into new vehicles is advocated as a way of producing ever higher fidelity rover analogues

Expedition one: A Mars analog research station 30-day mission

Expedition One was the first of a series of expeditions by a single crew to Mars-analog research sites around the world. Interdisciplinary studies in human factors, geology, biology, operations, and exploration technology required careful coordination among diverse groups and individuals. Research over the thirty days of the mission was organized into four Phases, which progressively linked to develop an integrated mission science scenario. Mars-analog rover, datalogger and suit technologies were tested while studying group processes and conducting task analyses to optimize extra-vehicular activity field work for an intensive geology and biology research program. Mars-analog studies classified according to three mission types are discussed, with examples. A description of the complete Expedition One program is given, with inclusion of the decisions made for the way the mission was organized and conducted, and preliminary conclusions are provided pending further analyses of accumulated data

Testing technologies and strategies for exploration in Australian Mars analogues: A review

Australia is an ideal testing ground in preparation for the robotic and human exploration of Mars. Numerous sites with landforms or processes analogous to those on Mars are present and the deserts of central Australia provide a range of locations for free-ranging Mars analogue mission simulations. The latest developments in testing technologies and strategies for exploration in Australian Mars analogues are reviewed. These include trials of analogue space suits based on mechanical counter pressure technology and the development of an analogue, crewed, pressurized rover for long-range exploration. Field science activities and instrumentation testing relevant to robotic and future crewed missions are discussed. Australian-led human factors research undertaken during expeditions to Mars analogue research stations and expeditions to Antarctica are also reviewed. Education and public outreach activities related to Mars analogue research in Australia are also detailed