MIT wins DARPA's red-balloon competition

Published 8 December 2009

To celebrate the 40th anniversary of the Internet, DARPA on Saturday launched ten red weather balloons in unannounced locations in the United States; the first team of spotters to identify the locations of the balloon received $40,000 in prize money; MIT researchers found a clever way to recruit hundreds of spotters, and the MIT team won

An MIT-organized network of spotters was the first to locate ten large red balloons placed around the United States on Saturday, winning a $40,000 prize from DARPA. Most of the cash will be distributed among the network’s members according to a simple formula whose design lay behind the MIT team’s success.

DARPA announced the balloon-finding competition to commemorate the 40th birthday of the Internet, and to investigate the ways that online social networks can be used to solve problems (DARPA Announces a $40,000 Red-Balloon Network Challenge,” 30 October 2009 HSNW). The agency announced victory for the MIT team on Saturday, saying it had taken less than nine hours to correctly locate all ten balloons. “The Challenge has captured the imagination of people around the world, is rich with scientific intrigue, and, we hope, is part of a growing ‘renaissance of wonder’ throughout the nation,” said DARPA chief Regina Dugan. “DARPA salutes the MIT team.”

Lewis Page writes that the MIT team used an elegant and rather simple means of recruiting its large nation-wide network of spotters. Every person registering with the team was given a unique link, which they could then propagate via e-mail, Web page, social network, or any other means they saw fit. New people could then click on this link and register with the MIT team, and in turn be given their own unique links with which to recruit others. The MIT database would thus know who had recruited whom.

On Saturday, a spotter managing to be first to get a correct location and balloon number to MIT came in line for a $2,000 payout from the team. The rest of the $4,000 prize money per balloon was assigned asymptotically (that is, all the money would be handed out only in the case of an infinite number of people in the chain) to the chain of people who found the spotter: $1,000 to the person who recruited the spotter him/herself, $500 to the person who recruited the recruiter, $250 to the person who recruited them, and so on until everyone in the chain was paid off. The money remaining from each $4,000, probably a small amount, will be donated to charity.

Page notes that the method is clever because it makes it worth someone’s while to join the MIT team, even though there is only a vanishingly small chance of actually finding a balloon oneself. For a few minutes’ work doing a signup and dropping a link onto one’s Web site — perhaps followed up with an e-mail/IM to your whole address book, for the old-school inclined — you come in line for potentially fifty, a hundred, maybe even a thousand dollars without so much as looking out of the window. MIT will no doubt have benefited, compared to other teams trying similar payout-splitting methods, from having an established reputation for both probity and technical competence, a high profile among the sort of people likely to be interested, and to have large online followings, and no profit motive.

It appears that there were not many fake balloons, and such as there were, were most probably bowled out by DARPA’s release of pictures just before the event showing what the real ones looked like.

The ten locations, shown here, were mostly in coastal states — none in the heart of the United States, except one balloon in Tennessee.