This image shows trajectory of (a) position and (b) orientation of pliers under repetitive laser irradiation without tracking. Grey lines indicate the projections of the trajectory in the respective coordinate planes. Credit: © the authors doi: 10.1117/1.OE.56.1.011007
Space debris from completed missions – inactive satellites, lens covers, fragments from spaceship disengagements – pose a serious and ongoing threat to active communication and navigation satellites used by billions of people on Earth. An article published by SPIE, the international society for optics and photonics, in Optical Engineering describes a new approach whereby debris orbiting in space could be pushed into Earth’s atmosphere by laser impulses, causing it to burn up.
High definition model of a set of pliers taken from Database of CAD models,” http://www.grabcad.com
Pieces even smaller than a smartphone represent danger to our ability to share information and find our way. While locations of major space debris are known, fragments <10cm are difficult to catalogue, and there are 10X more small pieces than large ones. Because of their remarkably high speeds – up to 15km/s small pieces of debris pose a serious threat for space flight and the operation of satellites such as those involved in communications and navigation.
In “Laser-based removal of irregularly shaped space debris,” Stefan Scharring, Jascha Wilken, and Hans-Albert Eckel of the German Aerospace Center describe a new approach where using high-energy laser pulses modify the orbit of debris and push it into the atmosphere, causing it to burn up. In the weightlessness of space, “a secondary effect of laser-induced damage, which is not immediately apparent in experiments on Earth”: when part of an object is ablated, or removed, using a laser beam, the recoil transfers momentum to the object. The authors simulate powerful laser oscillations to hazardous materials with the goal of modifying the debris’ orbit so that it re-enters and is destroyed by the atmosphere.
Results from Monte-Carlo simulations with EXPEDIT comprising 500,000 different initial positions and orientations of the target giving the averaged figures of merit ηaηa, ηdηd and the thrust angle αα for laser-induced momentum generation. Target geometries: plate (10 cm edge length), pliers (12-cm maximum dimension), and sphere (10-cm diameter). Gaussian laser spot profile with 50-cm diameter (full width half maximum, FWHM).
“Our work constitutes the transition from laboratory experiments with idealized flat targets and optimum laser alignment towards simulations of the real world scenario with arbitrarily shaped debris and limited laser pointing accuracy,” said the authors.
“Laser damage is usually considered to be a negative phenomenon, but this paper considers a significant positive application of laser-induced damage. In this study, the damage produced by laser beams serves a highly useful and positive purpose by cleaning up the space around Earth,” said Gruzdev. http://spie.org/x119947.xml
http://opticalengineering.spiedigitallibrary.org/article.aspx?articleid=2542221
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