# Acoustic Rocket Signatures Collected by Smartphones
###### Abstract  
Rockets generate complex acoustic signatures that can be detected over a thousand kilometers from their source. While many far-field acoustic rocket signatures have been collected and released to the public, very few signatures collected at distances less than 100 km are available. This work presents a curated and annotated dataset of acoustic signatures of 243 rocket launches collected by a network of smartphones stationed at distances between 10 and 70 km from the launch sites, resulting in 1089 individual recordings. Due to the frequency dependence of atmospheric attenuation and the relatively short propagation distances, higher-frequency features not preserved in most publicly available data are observed. The signals are time-aligned to allow for different segments of the signal (ignition, launch, trajectory, chronology) to be more easily examined and compared. Initial analysis of the features of these rocket launch stages is performed, observed features are compared to those found in the existing literature, and comparisons between signals from launches of different rocket types are made. The dataset is annotated and made available to the public to aid future analysis of the characteristics and source mechanisms of rocket acoustics as well as applications such as rocket detection and classification models. a 2025 6 202  
a sufficiently energetic low-frequency signal, but it severely limits the expediency at which detections can be made due to the relatively slow (compared to light) speed of sound. Acoustic signals generated by rocket launches have consistently been detected over the decades since humanity's first successful launches [4; 6; 7; 8; 9; 10; 11; 12; 13; 14]. Starting in the late 1950s, infrasound waves from rocket launches in Florida were detected by infrasound sensors at multiple stations in the eastern United States at ranges between 291 and 1594 km [6; 7; 10]. In 1971, [PERSON] and [PERSON] reported the observation of infrasound signals believed to be shock waves generated by the exhaust plumes of Apollo rockets as they flew over Bermuda at 188 km altitude [10; 14]. In the decades following these early observations, the annual number of rocket launches has increased dramatically, as has our ability to detect infrasound signals. Numerous rocket launch signals have been detected by IMS infrasound stations since the network's establishment, usually at great distances. Such signals have been analyzed in multiple studies [4; 8; 9; 12; 15], and thus the characteristics of far-field rocket signatures are generally well understood. Far fewer studies, however, have been conducted on acoustic rocket launch signals collected at shorter distances (<100 km). The existing literature includes a 2016 study that analyzed acoustic signals collected 7-100 km from the launch site of a four-stage sounding rocket [12], and results of a few studies analyzing acoustic signals collected at similar distances can be found in conference proceedings [13; 16; 17], but few data are currently publicly available. This relative dearth of nearer-field data limits advancement in the field of rocket acoustics for two related reasons. First, due to the atmospheric propagation effects previously discussed, much of the original signal's content is lost as it propagates, including features seen in data from previous studies [12; 13; 15; 16], limiting what can be learned about the source. Second, distortion of the signal during propagation makes relationships between characteristics and their source mechanisms more difficult to interpret in signals collected at longer ranges. Thus, we believe there is much to learn from analysis of nearer-field rocket launch acoustics. In order to conduct such an analysis, however, it is first necessary to curate a dataset of such signals. To this end, we established a semi-permanent network of low-cost, attributable sensors at a 10-70 km range from launch sites at the Kennedy Space Center and Cape Canaveral Space Force Station in Merritt Island and Cape Canaveral, FL, USA.