Bollettino della Comunità Scientifica in Australasia

Ambasciata d’Italia CANBERRA Aprile 2008

SPACE

9 Firing photons makes advance in space communication For the first time, physicists have been able to identify individual returning photons after firing and reflecting them off of a space satellite in orbit almost 1,500 kilometres above the earth. The experiment has proven the possibility of constructing a quantum channel between Space and Earth. Research published on Friday, 28 March, in the New Journal of Physics, discusses the feasibility of building a completely secure channel for global communication, via satellites in space, all thanks to advances in quantum mechanics. The research team, led by Paolo Villoresi and Cesare Barbieri from Padova University, , has taken intricate steps to fire photons directly at the Japanese Ajisai Satellite. The researchers have been able to prove that the photons received back at the Matera ground-based station, in southern Italy, are the same as those originally emitted. This news will be welcomed by communication companies, banks, and MI5-types worldwide as it paves the way for quantum-encrypted communication - the only form of communication that could ensure beyond any doubt that there are no eavesdroppers. Until now, quantum-encrypted communication has only been proven possible at distances up to about 150 kilometres, either down optical fibres or via telescopes. When sent down optical fibres, photons are dissipated due to scattering and adsorption and, when using telescopes, photons are subject to interfering atmospheric conditions. Anton Zeilinger, 2008 winner of the Institute of Physics’ premier award, the Newton Medal, was involved in the research. The team now believes that Space-to-Earth quantum communication is possible with available technology. The scientists write, “We have achieved significant experimental results towards the realization of a quantum communication channel, as well as how to actually adapt an existing laser ranging facility for quantum communication.” The team will now be furthering the research by making it possible to emit and receive quantum keys, uncrackable strings of 1s and 0s that enable quantum communication from an active sender in space. Very recently, the Italian Space Agency has funded the initial phase of this project. Taken from http://www.eurekalert.org/

9 Successful qualification firing test for Zefiro 23 On 27 March 2008, the second stage motor for - Europe's new small launcher - successfully completed a static firing test at the Salto Di Quirra Inter-force Test Range in , Italy. Ignition of the qualification model of the Zefiro 23 solid-propellant motor occurred at 13:15 CET. In just 14 seconds, the thrust reached 930 kN, equivalent to nearly 95 tonnes of force. This was the second and final firing test for the Zefiro 23, in which over 24 tonnes of propellant was consumed with a flame temperature of over 3000 K. The burn lasted approximately 75 seconds and initial results show the test to be a success. The combustion chamber pressure and motor thrust were well within the test prediction. Large amplitude movements of the thrust vector control system were executed - simulating worst-case manoeuvres - and the performance was very satisfactory. Additionally, modifications implemented in the nozzle design following the anomaly experienced during the previous Zefiro 9 test were proven to be effective. “The success of this test demonstrates the soundness of the design and rewards the enormous efforts of the team that has worked on the project,” stated Francesco Betti, Head of the Design Department at Avio's Space Division. The motor will now be transported back to Avio's facility at Colleferro (Italy) for a thorough inspection of all its components and the data obtained from the 400 sensors deployed during the test will be analysed in more detail. “The project team will rendezvous at Salto Di Quirra in June for the Zefiro 9 firing test,” announced Paolo Bellomi, Technical Director of ELV, the Vega launcher prime contractor. In the past 27 months, four Vega test firings have taken place at Salto Di Quirra, each one a milestone in the development of the Vega launcher. The Zefiro 23 is the second Vega solid rocket motor to achieve qualification, following the P80 first stage motor, which completed qualification testing in December 2007. “The teams of Avio, ELV, SABCA APP and of the Integrated Programme Team of ESA, CNES and ASI did a great job. This success paves the way for the Vega maiden flight,” said Stefano Bianchi, Head of the Vega Programme at ESA. Modified from http://www.eurekalert.org/

112 Bollettino della Comunità Scientifica in Australasia

Ambasciata d’Italia CANBERRA Aprile 2008

9 Artemis provides communications for Jules Verne ATV ESA's Artemis data relay satellite, controlled from Fucino (Italy) and with its mission control centre and Earth terminal located at Redu (Belgium), is providing communications between the Jules Verne ATV and the ATV Control Centre in Toulouse (France). Jules Verne ATV was launched from Europe's in French Guiana at 05:03 CET on 9 March. First contact between Artemis and the ATV was established at 06:46, exactly on schedule. Artemis communicates with Jules Verne, receiving telemetry and sending telecommands, each time the two spacecraft are within sight of one another. During every ATV orbit, there is around 40 minutes of continuous contact. Artemis will provide dedicated support to Jules Verne throughout the free-flying phase of its mission - up to the docking planned for 3 April. After docking, Artemis' data relay resource will be shared between ATV and ESA's Envisat Earth observation mission. Artemis is in geostationary orbit over the Atlantic Ocean. It has three main purposes: the provision of voice and data communications between mobile terminals in remote areas of Europe and North Africa, as well as in the Atlantic performing a key role within Europe's EGNOS satellite navigation system by broadcasting enhanced GPS and GLONASS signals for use by civilian 'safety critical' transport and navigational services the provision of inter-orbit satellite communication using advanced S- and Ka-band radio links and laser technology Modified from http://www.eurekalert.org/

9 New light on dark energy Astronomers have used ESO’s Very Large Telescope to measure the distribution and motions of thousands of galaxies in the distant Universe. This opens fascinating perspectives to better understand what drives the acceleration of the cosmic expansion and sheds new light on the mysterious dark energy that is thought to permeate the Universe. “Explaining why the expansion of the Universe is currently accelerating is certainly the most fascinating question in modern cosmology,” says Luigi Guzzo, lead author of a paper in this week’s issue of Nature, in which the new results are presented. “We have been able to show that large surveys that measure the positions and velocities of distant galaxies provide us with a new powerful way to solve this mystery.” Ten years ago, astronomers made the stunning discovery that the Universe is expanding at a faster pace today than it did in the past. “This implies that one of two very different possibilities must hold true,” explains Enzo Branchini, member of the team. “Either the Universe is filled with a mysterious dark energy which produces a repulsive force that fights the gravitational brake from all the matter present in the Universe, or, our current theory of gravitation is not correct and needs to be modified, for example by adding extra dimensions to space.” Current observations of the expansion rate of the Universe cannot distinguish between these two options, but the international team of 51 scientists from 24 institutions found a way that could help in tackling this problem. The technique is based on a well-known phenomenon, namely the fact that the apparent motion of distant galaxies results from two effects: the global expansion of the Universe that pushes the galaxies away from each other and the gravitational attraction of matter present in the galaxies’ neighbourhood that pulls them together, creating the cosmic web of large-scale structures. “By measuring the apparent velocities of large samples of galaxies over the last thirty years, astronomers have been able to reconstruct a three-dimensional map of the distribution of galaxies over large volumes of the Universe. This map revealed large-scale structures such as clusters of galaxies and filamentary superclusters ”, says Olivier Le Fèvre, member of the team. “But the measured velocities also contain information about the local motions of galaxies; these introduce small but significant distortions in the reconstructed maps of the Universe. We have shown that measuring this distortion at different epochs of the Universe’s history is a way to test the nature of dark energy.” Modified from http://www.eurekalert.org/

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