A competition at NASA that gave birth to models of colonization galactic


© China’s National University of Defence Technology / Xi’an Satellite Control Center / GTOC

During the contest, organized by the legendary Jet Propulsion Laboratory of NASA, the participants-physicists, mathematicians, and engineers in aeronautics and computer science-experienced – need to find effective solutions to extremely complex problems. After the management of space debris at the time of theprevious edition, it was necessary this time is off-peak the meninges to deliver an effective model of the colonization of our galaxy, it is what it is. According to the organizers of the GTOC, this is a “ how to foster innovation in the optimization of trajectories for interplanetary and inter-feeding of ideas between researchers in the fields of astrodynamic and optimization.”


The race was won by a chinese team, composed of members of the China’s National University of Defence Technology, and the Xi’an Satellite Control Center. Their model is available here.


The second place was also delighted by the chinese, Tsinghua university this time. However, their modeling has not yet been published. This is the Advanced Concepts Team of the European Space Agency (ESA), which completes the podium : here are the modeling outcome of their work.



On these simulations, each point represents a star considered as potentially habitable, while the lines represent the paths taken by the settlers.


In practice, each team receives a set of data representing approximately 100.000 star systems and a set of equations detailing with precision the orbital parameters of the celestial bodies in question. From this point on, the teams were left on their own and had to develop their own methodology to colonize the galaxy as efficiently as possible in 90 million years, with a number of constraints :



  • Each team starts its simulation with two mother ships (in blue), and two vessels, the so-called “fast” (in green).

  • Each mothership contains tencapsules of colony” that can colonize a star system each

  • Three ships, settlers can from each system two million years after it is colonized

  • Each system can only be colonized once

  • To simplify, we consider that the stars have zero mass. We deduce that there is therefore no’gravity assist (or the “slingshot”) possible

  • the orbital manoeuvres of the vessels are restricted in terms of time, speed and acceleration, without which the solution would be considered invalid


To designate the winner, the organizers have developed a complex formula, the type to convulse the allergic to math and is designed to make account of the colonization efficiency according to the main criteria of the test. If you want to take a look at it, it is available in page 4 of the instructions. To maximize its score, it was necessary to and colonize as many systems as 90 million years ago, with the spatial distribution of the most homogeneous possible, and by using the least amount of powere-propulsion possible.


A scenario very artificial, but a simulation nonetheless relevant


These constraints make this problem a real logistical headache. The choice of the destination of the first vessels, for example, is absolutely crucial. But if the exercise is fascinating intellectually, it was not intended to be a simulation completely realistic. Evidenced by the approximations mentioned in theproblem statement.


But this is not because it is not a plan of galactic conquest served on a tray that the experience is devoid of interest. At the time of the issue of the first travel across the galaxy will begin to arise, it will be necessary to solve problems of this type, but of a level of complexity much greater, without any approximation of comfort possible. Initiatives such as the GTOC allows one to work on a methodology and put current models to the test, while waiting to have the technology and the knowledge required to put into practice.


The Milky Way is at the age of about 13,500 million years old. This virtual conquest of 90 Ma is not even a small percent of the life of our galaxy ! An interesting point to note is that this figure is concordant with some serious studies on the issue.


What throw even more oil on the fire of the Fermi paradox, through which we try to understand if we are alone in the universe, and if not, why no species alien has not yet colonized the galaxy in this way. If you are not familiar with this fascinating thought experiment that is the Fermi paradox, this section of the SETI institute summarized in a very concise and elegant.

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