Probability distribution of the communication outages as a function of distance. Probability distribution of the communication outages as a function of distance. The database was gathered from a 5-min section of a general flight with 32 drones in a remote open-air setting. Each drone logged a 5-Hz sampling of the elapsed time since the reception of the last status packet from all other drones. This value [we call it timeout for simplicity but it actually also contains a small (<0.2 s) processing delay] was matched later with the position of the drones recorded accurately by each drone onboard. The distribution shows logs from all drones (1,349,490 data points in total), and it is normalized for each row (distance) separately. Color indicates timeout probability in each bin for a given distance. Average timeouts with SD and with the number of data points are indicated on the right for 50-m distance binning, whereas the black line on the plot indicates average and SD of timeout for each distance bin of 10 m. Database is very sparse and thus less accurate above 150 m, but as a general tendency, communication is most stable between close-by drones, whereas outages were more frequent and longer with increasing distance. Gábor Vásárhelyi et al. Sci. Robotics 2018;3:eaat3536 Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works