COSMIC at the Very Large Array

The National Science Foundation Karl G. Jansky Very Large Array (VLA) is one of the world’s most powerful radio telescopes. Located on the Plains of San Agustin in central New Mexico and operated by the National Radio Astronomy Observatory (NRAO), the VLA consists of 27 dish antennas spread across the desert. Together, these antennas work as a single giant telescope, allowing astronomers to study everything from distant galaxies to nearby planets using radio waves invisible to the human eye.

Installed at the VLA is COSMIC, the Commensal Open-Source Multimode Interferometer Cluster. COSMIC is a new digital system that records data during observations already being made by the telescope, without interfering with the primary science goals. This approach—called commensal observing—allows researchers to collect additional scientific data at the same time, making the most of the VLA’s observing time.

COSMIC receives a copy of the radio signals collected by each of the VLA’s antennas and processes them in real time using a combination of specialized electronics and high-performance computers. These signals are sorted into different frequency ranges and analyzed to extract scientifically useful information. The system then distributes the data to powerful computer servers equipped with graphics processing units (GPUs), which are well suited for handling the large data volumes produced by modern radio telescopes.

Collaboration and Operations

COSMIC is the result of a large international collaboration, with a strong emphasis on U.S.-based researchers and technology development. While the system is physically located at the VLA, it is operated by the SETI Institute in California in collaboration with the University of California, Berkeley and Breakthrough Listen.

Searching for Technosignatures

One of COSMIC’s primary science goals is the search for technosignatures—measurable signals or effects that could indicate the presence of technology developed beyond Earth.There are many ways to carry out technosignature research, but COSMIC looks for radio signals. Thanks to a long wavelength, these signals can travel vast distances through space, and they are commonly used by human technologies such as satellites, radar, and communications systems.

COSMIC is uniquely designed for this type of research. Because it operates continuously alongside other VLA observations, it can survey large regions of the radio spectrum across many different types of astronomical targets. This includes nearby stars that host known exoplanets, distant star systems, and even other galaxies. Rather than observing only a small number of targets, COSMIC enables broad, long-term searches that greatly increase the chances of detecting rare or unexpected signals.

The system searches for signals with characteristics that are difficult to explain by natural astrophysical processes. For example, COSMIC helps identify extremely narrow radio signals or signals that slowly change frequency over time—patterns commonly produced by human-made transmitters on Earth. While the presence of such signals does not automatically imply extraterrestrial technology, they provide important candidates for further study.

Technosignature research with COSMIC also benefits the wider astronomy community. By carefully identifying and cataloging human-made radio interference, COSMIC helps astronomers better understand and filter out these signals from other types of observations. This improves data quality across many areas of radio astronomy.

By combining continuous observing, flexible software, and advanced signal processing, COSMIC represents a powerful new approach to the search for technological activity beyond our solar system—while simultaneously advancing our understanding of the radio universe as a whole.