[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/en\/article\/modal\/6005\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n 1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n 2) Linking back to our original story\u003Cbr \/\u003E\n 3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n \n\u003Cdiv\u003E\n \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003ECrossing the solar system on a 400 square km solar sail\u003C\/h2\u003E\u003Cp\u003EThe idea, developed by Dr Pekka Janhunen from the Finnish Meteorological Institute, is to stretch out one hundred 20-kilometre-long microscopic tethers around the spacecraft like a giant starfish.\u003C\/p\u003E\u003Cp\u003EA solar sail is meant to give a spacecraft gentle but constant acceleration due to the force of photons from the sun hitting it and pushing it forward. However, the biggest problem with that idea is the sail must be extremely large in order to give it power that is comparable to a chemical thruster, and that makes it too heavy.\u003C\/p\u003E\u003Cp\u003EAs part of the EU-funded ESAIL project, Dr Janhunen is exploring an avenue that could skirt this obstacle. The project is pioneering a sail design that intercepts charged particles in the solar wind. Unlike rays of sunlight, the momentum of these particles can be harnessed by deflecting them with weightless electric fields.\u003C\/p\u003E\u003Cp\u003EThe field will be generated by charging 20-kilometre-long, aluminium wires \u2013 each just 50 micrometres in diameter and weighing barely 200 grams.\u003C\/p\u003E\u003Cp\u003EAn electric field would spread 200 metres around each tether, making a total cross-section of 400 square kilometres. That could propel a spacecraft across the inner solar system faster than current propulsion systems, Dr Janhunen said.\u003C\/p\u003E\u003Cp\u003EAlthough the microscopic diameter of the electric solar sails makes them light, it also makes them vulnerable. Timo Rauhala, an electronics engineer at the University of Helsinki, has therefore developed a way to fasten them into resilient tethers.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMicrometeoroids\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018We intertwine the wires into a scaffold of metal loops that repeats over kilometres,\u2019 he said. \u2018Because the structure is composed mainly of empty space, micrometeoroids are unlikely to break all four wires at any one spot.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cspan class=\u0022img_legend\u0022 style=\u0022float: left;\u0022\u003E\u003Cfigure role=\u0022group\u0022\u003E\n\u003Cimg alt=\u0022Dr Pekka Janhunen, from the Finnish Meteorological Institute.\u0022 height=\u002288\u0022 src=\u0022\/research-and-innovation\/sites\/default\/files\/hm\/Dr-Pekka-Janhunen.jpg\u0022 title=\u0022Dr Pekka Janhunen, from the Finnish Meteorological Institute.\u0022 width=\u0022200\u0022\u003E\n\u003Cfigcaption class=\u0022tw-italic tw-mb-4\u0022\u003EDr Pekka Janhunen, from the Finnish Meteorological Institute.\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003Cem\u003EDr Pekka Janhunen, from the Finnish Meteorological Institute.\u003C\/em\u003E\u003C\/span\u003E\u003C\/p\u003E\u003Cp\u003EComputer simulations estimate that, while micro-collisions would sever each 20-kilometre wire in a matter of minutes, the chances of a full fracture in any of the 100 tethers used in a complete propulsion system is no higher than 1 % over a five-year period.\u003C\/p\u003E\u003Cp\u003EThe tethers also remain elastic and can be rolled onto reels and packed onto a spacecraft. \u2018We have automated the entire bonding process and have shown that it works on a kilometric scale,\u2019 said Dr Janhunen. \u2018The next step is to test it in space.\u2019\u003C\/p\u003E\u003Cp\u003ETo field-test their invention, the ESAIL consortium has partnered with another EU-funded project, EstSpacE. The project received EUR 1 million to help in the construction of ESTCube-1, Estonia\u2019s first satellite, a nanosatellite, made by more than a hundred undergraduate students at Tartu University, Tallinn University, and the Estonian Aviation Academy.\u003C\/p\u003E\u003Cp\u003EAs a result of the collaboration with the Finnish Meteorological Institute and the German Aerospace Centre, ESTCube-1\u2019s primary mission \u2013 to deploy a 10-metre-long prototype in space \u2013 is now getting underway. The payload was piggybacked on a European Space Agency launch in May 2013 and now orbits the earth 650 kilometres up.\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003E\u2018The real advantage of electric solar sails is that they use no fuel \u2026 they could essentially make space flight lighter, easier and cheaper.\u2019\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EDr Pekka Janhunen, the Finnish Meteorological Institute \u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003ESince the launch, they have been working on the code required to bring the satellite under control using four on-board electromagnets, as they\u2019re afraid the sail might break if it is deployed too early.\u003C\/p\u003E\u003Cp\u003EAccording to Dr Mart Noorma, who was involved in the project, they should be in a position to deploy the sail, by unreeling it from the spacecraft, in the coming months.\u003C\/p\u003E\u003Cp\u003E\u2018This is something you can\u2019t practice on earth,\u2019 he said. \u2018Deploying the electric solar sail will be an all-in, single-try gamble. The students taking part in the project understand this and are not taking any chances with it.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ELightweight missions\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EIf the electric solar sail can be proven to work in space, it could ultimately replace chemical thrusters on lightweight interplanetary missions.\u003C\/p\u003E\u003Cp\u003E\u2018The real advantage of electric solar sails is that they use no fuel,\u2019 said Dr Janhunen. \u2018Also, in cases where they make planetary fly-bys (where gravity is used to accelerate a spacecraft) unnecessary, they relax constraints on rocket launch windows. They could essentially make space flight lighter, easier and cheaper.\u2019\u003C\/p\u003E\u003Cp\u003EHowever, he also stressed the limitations of the technology. The thrust provided by the solar wind is of no use for lifting objects out of earth\u2019s orbit, and it fades quickly beyond the asteroid belt, but it could be used for missions to the inner planets such as Mars.\u003C\/p\u003E\u003Cp\u003EInnovation like this illustrates a growing trend in the space industry. Privatised rocket launches and cheaper electronics are making it easier to test new ideas.\u003C\/p\u003E\u003Cp\u003E\u2018Projects costing millions of euros cannot afford to experiment with unproven technology,\u2019 said Dr Noorma. \u2018But successful concepts and components tried out in nanosatellites like ESTCube-1 can later be picked up by more conventional players.\u2019 \u003Cdiv class=\u0022moreinfoblock\u0022\u003E\n \u003Ch3\u003ENuclear spacecraft\u003C\/h3\u003E\n \u003Cp\u003EThere is no shortage of alternatives for more energy-intensive missions. The EU-funded DiPoP project has investigated several potentially disruptive technologies for generating propulsion and power in space.\u003C\/p\u003E\u003Cp\u003EFor larger-scale challenges, such as manned flights to Mars or expeditions to deflect asteroids on a collision course with earth, a nuclear power-driven spacecraft could be best suited to navigating the interplanetary void.\u003C\/p\u003E\u003Cp\u003EDr Claudio Ferrari from the ISIS R\u0026amp;D centre in Rome said that the fuel efficiency of a nuclear propulsion system could be around ten times higher than the best chemical thrusters around today. The follow-up MEGAHIT project is bringing together partners from the EU and Russia to produce propsals for even higher-power nuclear electric space propulsion systems.\u003C\/p\u003E\u003Cp\u003EFor details, visit \u003Ca href=\u0022http:\/\/www.megahit-eu.org\/about-megahit.html\u0022 target=\u0022_blank\u0022\u003Ehttp:\/\/www.megahit-eu.org\/about-megahit.html\u003C\/a\u003E\u003C\/p\u003E\n\u003C\/div\u003E\n\u003C\/p\u003E\u003C\/textarea\u003E\n\u003C\/div\u003E\n\n \u003Cdiv id=\u0022edit-body-content--description\u0022 class=\u0022ecl-help-block description\u0022\u003E\n Please copy the above code and embed it onto your website to republish.\n \u003C\/div\u003E\n \u003C\/div\u003E\n\u003Cinput autocomplete=\u0022off\u0022 data-drupal-selector=\u0022form-bpxkl2oga6aoey9iiql1e1nrhgqzyirdek-vxlqyt-i\u0022 type=\u0022hidden\u0022 name=\u0022form_build_id\u0022 value=\u0022form-BpXKl2ogA6aOey9IIQl1e1NRHGQzYIrDEK_vxLQyt_I\u0022 \/\u003E\n\u003Cinput data-drupal-selector=\u0022edit-modal-form-example-modal-form\u0022 type=\u0022hidden\u0022 name=\u0022form_id\u0022 value=\u0022modal_form_example_modal_form\u0022 \/\u003E\n\u003C\/form\u003E\n\u003C\/div\u003E","dialogOptions":{"width":"800","modal":true,"title":"Republish this content"}}]