{"id":1540,"date":"2011-05-13T09:33:31","date_gmt":"2011-05-13T09:33:31","guid":{"rendered":"http:\/\/www.joswassink.nl\/insight\/?p=1540"},"modified":"2011-05-13T09:33:31","modified_gmt":"2011-05-13T09:33:31","slug":"high-ropes","status":"publish","type":"post","link":"https:\/\/www.joswassink.nl\/insight\/?p=1540","title":{"rendered":"High Ropes"},"content":{"rendered":"<p><strong> <\/strong><\/p>\n<div id=\"attachment_1541\" style=\"width: 310px\" class=\"wp-caption alignleft\"><strong><\/strong><strong><a rel=\"attachment wp-att-1541\" href=\"http:\/\/www.joswassink.nl\/insight\/?attachment_id=1541\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1541\" class=\"size-thumbnail wp-image-1541\" title=\"schighropes\" src=\"http:\/\/www.joswassink.nl\/insight\/wp-content\/uploads\/2011\/05\/schighropes-300x168.jpg\" alt=\"\" width=\"300\" height=\"168\" \/><\/a><\/strong><p id=\"caption-attachment-1541\" class=\"wp-caption-text\">The red ball is about to be ejected towards Earth, pulling 30 kilometres of high-strength fibre behind it. (Photo: ESA)<\/p><\/div>\n<p><strong>Space ropes and ribbons may have many applications, ranging from  futuristic space-lifts to the more realistic destroyers of space debris.<\/strong><\/p>\n<p>After ten years of relative quiet, interest in space tethers is  picking up, Michiel Kruiff (MSc), of Estec in Noordwijk, observes. He  graduated on the subject of space tethers from TU Delft&#8217;s faculty of  Aerospace Engineering. Together with Delta-Utec&#8217;s Erik van der Heide,  Kruijff proposed a space tether mission to the European Space Agency  (ESA), and then got lucky when the first Ariane V rocket exploded (4  June 1996). ESA decided to fire another Ariane without a payload, as a  means of restoring confidence in the launcher, which provided Kruijff  and colleagues with an opportunity for a free ride into space.<!--more--><\/p>\n<p>The  mission, called Young Engineer&#8217;s Satellite (Yes), consisted of a 35 km  Dyneema rope attached to a 12.5 kilogram mass. Once in orbit the mass  would be ejected, pulling the rope behind it into space. Once the height  difference becomes more than 500 metres, the gravity gradient is large  enough to start pulling out the rope by the weight of the mass.<\/p>\n<p>Lucky  as they were with the free launch, so unfortunate was the timing.  Kruijff explains that if the satellite had been launched in the  afternoon, sunlight would have pushed the rope \u2013 after it had been cut &#8211;  towards the<\/p>\n<p>atmosphere, where it would simply burn up at  re-entry. But since the launch on 30 October 1997 took place in the  morning, the Yes satellite ended up on the wrong side of the globe and  ESA would not permit deployment for fear that the rope would float  around indefinitely. \u00a0Eventually Kruijff decided to first cut the rope  and then eject the mass.<\/p>\n<p>Ten years later, Kruijff got a second  chance with the Yes2 mission, which was launched on 14 September 2007.  This time the 8 kilogram ejection mass contained a 6 kilogram capsule,  called Fotino, which was to return to Earth as a demo for Space Mail.  Despite some hiccups the mission was largely successful and won Kruijff  an entry in the Guinness Book of Records for having realised the tallest  structure (32 km) in space.<\/p>\n<p>The most useful applications of space  tethers might be as conducting ribbons, which experience a Lorentz  force in the Earth&#8217;s magnetic field and can thus pull floating space  debris down to the atmosphere. Kruijff: \u201cWithin a couple of years, 98  percent of the space junk can be eliminated.<\/p>\n<p><em>\u201dMichiel Kruijff:  &#8216;Tethers in Space, A Propellantless Propulsion In-Orbit Demonstration&#8217;,  30 May 2011, PhD supervisors: Prof. Wubbo Ockels and Prof. Eberhard  Gill.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Space tethers like ropes and ribbons may have many applications, ranging from futuristic space-lifts to the more realistic destroyers of space debris, says Michiel Kruijff (ESA)<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,6],"tags":[404,407,431],"class_list":["post-1540","post","type-post","status-publish","format-standard","hentry","category-articles","category-delta","tag-space-debris","tag-spaceflight","tag-tethers"],"_links":{"self":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/posts\/1540","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1540"}],"version-history":[{"count":0,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=\/wp\/v2\/posts\/1540\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1540"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.joswassink.nl\/insight\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}