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Project ELT

Czech scientists are providing proof of the theory of relativity in the framework of space project

Prague, June 28th 2011 – The implementation of ambitious space project „European Laser Timing“ (ELT), with the involvement of Czech scientists, entered the final phase. The main goal of the project is to synchronize a pair of extremely precise atomic clock through laser pulses, one on Earth and another in space. The side-effect of such experiment will be a confirmation that time runs at both places differently. This way, the Einstein’s theory of relativity should be proved.

Project ELT is purely Czech contribution to important international experiment ACES (“Atomic Clock Ensemble in Space”), which major goal is to evaluate the functionality of a new generation of extremely precise atomic clock in microgravity and perform independent time measurements on Earth and in space. The European Space Agency plays the role of main coordinator, which supports the involvement of public and private subjects through regional partners.

ELT device is going to be installed onboard ISS, particularly on the Columbus module, together with ACES hardware in 2015. The development of the ELT device is provided by the Czech Space Research Centre and the Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in Prague (CTU). The information of precise time will be transferred between ISS and Earth by laser pulses. There will be a conventional network of laser ground stations for such laser transfer, which is usually used for measurement of distance to orbiting satellites. Laser deflectors are going to be placed at the ISS in order to perform precise distance measurement including the fast photon detector determining the precise time moment of incoming laser pulse.

“The key element of the whole device is a special optical detector, developed by the Faculty of Nuclear Sciences and Physical Engineering CTU, called Single Photon Avalenche Diode (SPAD), capable to detect individual photons”, explains the Czech contribution to the project Michal Vaclavik from the Czech Space Office. “The detector and the whole estimation method is already used for the precise time measurement onboard 3 Chinese navigation satellites Compass and onboard Jason 2 satellite operated by NASA and CNES”, adds to the topic Vaclavik. The research and development of SPAD detector was started at the CTU already in 1984.

“Our department has raised already wide experience with the space research. SPAD detector has been installed at 25 ground stations, designed for laser distance measurement of satellites. These ground stations are disseminated around the globe besides Antarctica. We also developed a laser altimeter for the Russian probe Mars 96 and for American probe Mars Polar Lander. Current project ELT is the latest use of our unique methodology, developed in our department,” describes the history of the development of the scientific hardware professor Ivan Prochazka from the Faculty of Nuclear Sciences and Physical Engineering CTU.

The ELT project currently entered a new phase, in which the flight model for the ISS is going to be produced. The whole ACES experiment is expected to be launched by middle of 2015. Already now it becomes clear, that the Czech contribution will be very useful for the whole experiment.

“Project European Laser Timing is a typical example of successful cooperation of a private company with the state owned research institution. This is the long-term goal of research institutions, such as European Space Agency”, closes Vaclavik.