Signal Tide · A sound and extraterrestrial radio installation


Signal Tide is a sound and extraterrestrial radio installation artwork by Kata Kovács and Tom O’Doherty. The work combines real-time signals from an abandoned satellite currently orbiting the earth (the LES-1, launched in 1965) with specially-commissioned music and sound, created by David Bryant (of Godspeed You! Black Emperor and Hiss Tracts), Drew Barnet, and James Hamilton, in collaboration with Kovács/O’Doherty.

Signal Tide was initially presented at Los Angeles County Museum of Art, from September 21.–24., 2017.

Research and development of the work was supported by the LACMA Art + Technology Lab.

About the work

Signal Tide is an installation which combines audio, derived from the signal of the LES-1 satellite, with a generative sound accompaniment based on sacred harp singing melodies.

The LES-1, manufactured in the early 1960s at MIT, in Boston, Massachusetts, was launched in 1965. It functioned for the following two years, but it then ceased to transmit signals in 1967, and was abandoned as cold-war-era space-junk. However, in 2013, signals from the LES-1 were unexpectedly received again, for the first time in 46 years. This resurrected spacecraft is still giving its ghostly signal, which can be received at 237mHz on any VHF antenna. The satellite is now also seemingly tumbling slowly around its own axis every few seconds, as it orbits the earth — this means that it gives an unstable but steady signal, with distinctly-perceivable gaps caused by this tumbling action.

Signal Tide combines audio, derived from the live feed of the satellite’s signal, with a musical ‘answering’ signal, in real time, as the satellite passes overhead above the site of the installation. The LES-1, an artificial moon and a relic of a different era, pulls an earthbound tide of sound toward it, in a fleeting accompaniment, as it passes overhead on its looping extraterrestrial pilgrimage.

Presentation dates and times of Signal Tide at LACMA, Los Angeles:

Date: Time:
Thursday, 21. Sept., 2017 6:50am – 7:41am
9:29am – 10:20am
12:08pm – 12:58pm
Friday, 22. Sept., 2017 7:08am – 7:59am
9:47am – 10:38am
12:26pm – 1:15pm
Saturday, 23. Sept., 2017 7:26am – 8:17am
10:05am – 10:56am
12:44pm – 1:33pm
Sunday, 24. Sept., 2017 7:44am – 8:35am
10:23am – 11:14am
1:03pm – 1:50pm

About the music

The music for Signal Tide has been specifically written and recorded for use in this work. The sound played in the work is generative, and so never repeats in the same way — thus each pass of the satellite has its own unique accompaniment. The recordings include contributions from David Bryant and Sophie Trudeau of Godspeed You! Black Emperor, Drew Barnet, James Hamilton, a choir of Montréal sacred harp singers, and others — a full list is provided below.

This generative musical accompaniment is derived from melodies used in sacred harp hymns and anthems. Sacred harp singing is a distinct tradition of American and Canadian shape-note choral music, which has a centuries-long history as Christian sacred music, with distinct ‘southern’ and ‘northern’ schools. One of the areas where the ‘northern’ tradition is particularly strong is in Boston and the wider New England area. The LES-1 satellite was designed and built in Boston, at Lincoln Laboratory in MIT, and so Signal Tide serenades the satellite with music that is part of the folk traditions of a place which is, in an anthropomorphised sense, its home and point of origin.

Each pass of the LES-1 (during daylight hours and within antenna range of the site of the installation) lasts approximately 35 to 40 minutes. The installation is active only during these passes. During these times, a row of overhead speakers plays the audio derived from the live signal of the satellite. Simultaneously, a series of ground-level speakers plays a unique, generative accompaniment, accompanying the satellite as it passes overhead. The satellite then takes approximately three hours to circle the earth before returning, and so these times when the installation is active are approximately three hours apart from each other.

The lyrics of sacred harp songs often consider themes of ephemerality, hope, and transcendence. The metaphorical potential of these beautiful, haunting songs, as an accompaniment to the weary and lonely LES-1, has been an artistic point of departure in considering the musical elements of this work. The process of research for the work has been ongoing since mid-2016, and the majority of the music used in the work was recorded in The Pines recording studio, Montréal, in April 2017. The process through which the music is played and generatively combined is software-defined, using Substrate.

Participants and contributors:

  • David Bryant
  • Drew Barnet
  • James Hamilton
  • Sophie Trudeau
  • Esther Wade, Patrick DeDauw, Xarah Dion, Philippe Doyle-Gosselin
  • Collin Findlay
  • Elena Horgan
  • Tim Eriksen and Zoë Darrow
  • Kata Kovács and Tom O’Doherty

Work on this project has also been assisted by singer, musician, and sacred harp scholar Tim Eriksen.

Sophie playing viola

Fleeting Days


Rehearsing and recording at The Pines

Technical development

The process of researching the work has been documented on the Signal Tide blog on Medium, which gives an overview of many of the technical steps that have been involved in developing the work. The project has also been profiled on LACMA’s Unframed blog.

The development of the work is deeply indebted to the assistance and collaboration of Kris Slyka. The development was assisted by Meharban Sobti, Lilian Haney, Jeremy Fields, Paul Weiss, Devin Williams, and Han Lin at SpaceX; Tom Spilker, Dan Goods, and Stephan Esterhuizen at NASA JPL; Bart O’Doherty; Scott Cutler at Southern Stars; and R. Kevin Nelson and Will Light.

Excerpt from the signal of the LES-1 satellite, derived from I/Q data recorded in September 2016, in Lunow-Stolzenhagen, Germany, showing the gaps in transmission approximately every four seconds.

About Kovács/O’Doherty

Kovács/O’Doherty (Kata Kovács and Tom O’Doherty) have worked as a collaborative duo since 2011. Their work combines elements of durational and time-based art, minimalist and electroacoustic music and sound, movement, and video. This work often applies rigorous processes to simple but frequently-overlooked phenomena – they are interested in processes, sounds, and movements that come close to imperceptibility, and the ways in which this material can be transformed through layering, rhythm, pattern, and repetition. They live and work in Berlin, Germany.

Here’s how to say the name:

Kovács/O’Doherty, tracking satellite signals, LACMA rooftop, Los Angeles, USA, September 2017

Downloads and resources

The following downloads and resources are available for free use.


  • Signal Tide representative image (1418 × 1418 pixels, 72dpi)
    Spectrogram image excerpt from the signal of the LES-1 satellite, showing the gaps in transmission approximately every four seconds, and the ‘tilt’ in the signal caused by the doppler shift of the signal as the LES-1 crosses the sky.
  • Kovács/O’Doherty portrait (3723 × 2793 pixels, 72dpi)
    Kovács/O’Doherty, tracking satellite signals, Stolzenhagen, Germany, May 2017.



  • Signal Tide excerpts playlist (SoundCloud)
    Excerpts from audio used in the installation. The first track is based on the sacred harp hymn Fleeting Days, the second track is an excerpt from audio derived from the signal of the LES-1 satellite.


Signal Tide — LES1

Signal Tide main image (cropped version) — spectrogram image excerpt from the signal of the LES-1 satellite, recorded in September 2016.


The research process that has preceded the presentation of Signal Tide has been supported by the LACMA Art + Technology Lab. Kovács/O’Doherty were announced as one of the recipients of the 2016 Art + Technology Lab Awards in May 2016, by Adjunct Curator Amy Heibel, and Program Director Joel Ferree, and the Lab has facilitated assistance for research on Signal Tide from supporting partners, including invaluable help from SpaceX and NASA’s Jet Propulsion Laboratory.

The presentation of the work has been supported by the LACMA Art + Technology Lab, as well as has been part-funded by the Berlin Senate Department for Culture and Europe.