The automatic deployment of these metallic blue 'wings' and the activation of the on-board navigation systems will transform the 20-tonne Automated Transfer Vehicle (ATV) into a fully automatic spaceship navigating towards the International Space Station (ISS).
"The test went well despite the fragility of the solar arrays. It proves that the ATV solar power, designed for up to six months in orbit, is working fine", said Detlef Otto, who is in charge of the ATV power system for ESA and who supervised the test.
The bus-sized ATV spacecraft had to be rotated into a horizontal position for the integration of the solar panels. The panels were fully deployed and then folded again and latched, ready to fly. Each panel was minutely inspected before final integration.
Since the solar arrays have been engineered to work in weightlessness, their 9.15 m-long structure is so light that they cannot be unfolded on Earth without being supported by several cables. “Otherwise, in Earth's gravity, the solar panels could not hold their own weight of 7kg without bending irreversibly”, said Detlef Otto. The system is so sensitive that during the arrays' deployment tests even the barely noticeable air conditioning flow had to be turned off in the huge integration hall.
But the five-year effort to develop the ATV 'wings' and their rotation mechanisms, that enable the outstretched solar panels to constantly track the Sun as the ATV circles the Earth, have been a challenge until recently. During several years of testing, the state of the art solar panels have been deployed and checked about 50 times by the engineers at Dutch Space, who built them.
Some tricky issues related to the solar panel rotation mechanisms, built by Thales Alenia Space in Cannes, France, have put some pressure on the timeline. Constant tracking with these mechanisms permits the most efficient generation of electrical power for the ATV in orbit and during its six-month long ISS docking phase.
The four 4-kg rotation mechanisms have been checked and removed from the ATV several times to solve some minor problems of resistance and lately, some contamination issues due to metal particles found in one of the mechanisms.
Once deployed, the four solar arrays provide electrical power to ATV and to its rechargeable batteries so that the eclipse periods in orbit can be bridged. Silicon-based solar cells, developed and produced in Germany by RWE Space Solar Power, cover the four panels per array with a total surface of 33.6m² (4 x 8.4m²), and are able to produce an average of 4800 Watts.
Mounted on the ATV service module, the four sun-tracking arrays are totally independent and can get the best orientation to the Sun thanks to the rotating mechanisms. The ATV solar power sources are built to tolerate the loss of one of the four independent arrays and their respective power chains.
“Now we feel confident, although the next challenge will be the 6-month attached phase with the Station because he ATV wings will have to withstand millions of vibrations and oscillations due to the ISS crew activity and the Station jets”, said Detlef Otto.
Markus Bauer | alfa
From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison
Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News