COSMIC and Next-Generation SETI: Achievements, Challenges, and Future Directions

Abstract

The Commensal Open-Source Multimode Interferometer Cluster (COSMIC) represents a transformative approach to SETI, dramatically expanding both observing time and sky coverage by operating commensally with the Karl G. Jansky Very Large Array (VLA). This paper examines COSMIC's achievements - scanning ~3,000 stars per hour and surveying over 950,000 fields in its first 11 months - while critically assessing its limitations compared to targeted efforts like Breakthrough Listen. We quantify sensitivity thresholds (detecting 10^11-10^16 W EIRP transmitters depending on distance), discuss null result implications for technosignature prevalence, and explore how AI and robotics (machine learning classifiers, autonomous calibration via drones) can enhance future searches. The analysis demonstrates that COSMIC complements rather than supersedes existing SETI initiatives, forming part of a multi-pronged strategy essential for addressing the vast cosmic haystack.

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1. Background and Significance

The Commensal Open-Source Multimode Interferometer Cluster (COSMIC) is a cutting-edge SETI experiment attached to the Karl G. Jansky Very Large Array (VLA). COSMIC operates commensally – it taps into the VLA's data stream during normal astronomical observations without interrupting them. This approach effectively grants COSMIC continuous observing time, a dramatic improvement over earlier SETI searches that relied on scarce dedicated telescope time.

Previous surveys often took years to examine just a few thousand stars due to limited telescope access. In contrast, COSMIC can listen 24/7, monitoring up to ~3,000 stars per hour. Leveraging the VLA's 27-dish array, COSMIC can form multiple simultaneous beams and survey an unprecedented volume of sky.

Scale and Scope

Researchers anticipate covering about 80% of the sky (down to declination –40°) and scanning on the order of millions of star systems across a wide frequency range (∼0.75–50 GHz). Such scale makes COSMIC approximately 1000 times more comprehensive than any prior radio technosignature search, marking it as a bellwether for the future of SETI efforts.

By dramatically expanding both sky coverage and bandwidth, COSMIC aims to push SETI into a new regime of sensitivity and scope, potentially offering transformative insights into the detection of extraterrestrial technology.

2. Achievements of COSMIC to Date

Despite being relatively new, COSMIC has already notched significant milestones:

2.1 Observational Performance

Since beginning operations in early 2023, COSMIC has:

• Recorded data from all VLA antennas with up to 1.2 GHz bandwidth
• Observed over 950,000 fields in ~11 months
• Captured data from over 400,000 sources in one month alone
• Scanned ~2,000–3,000 targets per hour continuously

This commensal strategy means the project is on track to perform one of the largest technosignature searches ever, potentially examining nearly 10 million star systems over two years.

2.2 Technical Capabilities

COSMIC's backend demonstrates remarkable technical sophistication. The system processes extremely fine frequency channels down to a few Hz, enabling nanosecond-scale pulse detection for transient signals while maintaining real-time autonomous calibration and correlation. This capability was validated by successfully detecting Voyager 1's faint carrier signal from a ~20 W transmitter at ~159 AU distance. The multi-beam approach allows for localizing candidate signals and effectively discriminating true celestial signals from radio-frequency interference.

2.3 Array Advantage

The multi-beam approach excels at discriminating signals through a simple but powerful principle: true celestial signals appear in specific beams based on their sky location, while broad RFI (radio-frequency interference) hits all beams equally. This fundamental difference enables real-time signal validation without requiring follow-up observations.

3. Limitations and Comparative Analysis

3.1 Commensal Constraints

As a commensal system, COSMIC faces inherent limitations. It cannot control telescope pointing or frequency selection, remaining entirely dependent on VLASS and other VLA programs for targets. This means coverage is not optimized for specific SETI targets, and some potentially interesting systems may not receive deep observations.

The comparison with Breakthrough Listen highlights different search philosophies: COSMIC casts a wide net with shorter dwell time per object, while Breakthrough Listen uses a narrower net with deeper exposure per target. BL's initial programs targeted ~1,700 nearby stars with tens of minutes per star, exemplifying the fundamental trade-off between quantity of targets and per-target sensitivity.

3.2 Frequency Coverage and Instrumentation

COSMIC's Phase I currently covers 2–4 GHz commensally with VLASS, with plans to extend up to 50 GHz in the future. For comparison, Breakthrough Listen surveys 1–12 GHz plus conducts optical and laser searches, providing complementary frequency coverage.

Array processing presents significant technical challenges: complex real-time correlation and beamforming are required, demanding critical antenna phase calibration across all 27 dishes. Phase errors can potentially reduce sensitivity, a particular concern given that COSMIC is built from off-the-shelf hardware and open-source software rather than purpose-built infrastructure.

3.3 Search Biases and Assumptions

Both COSMIC and Breakthrough Listen target narrow-band radio signals as primary technosignatures, which introduces inherent biases. The search assumes powerful transmitters or beacons and is optimized for beacon-like transmissions, potentially missing spread-spectrum or frequency-hopping signals and limiting detection of unconventional signal types.

The RFI challenge remains formidable: COSMIC detects millions of signals per hour, with the vast majority being terrestrial interference. Despite the enormous data volume examined, no confirmed technosignatures have emerged to date, necessitating extensive post-processing and machine learning approaches to manage the signal deluge.

3.4 Follow-up Limitations

COSMIC cannot repoint the VLA on the fly for candidate signals, instead requiring follow-up proposals or coordination with other telescopes. This contrasts with Breakthrough Listen, which can repoint immediately for on-off confirmation tests.

To mitigate this limitation, COSMIC has arranged agreements with VLBA, ATA, Parkes, and other facilities for rapid follow-up, targeting a response time within one week. However, this latency could prove critical if signals are intermittent or short-lived, potentially missing transient phenomena that don't repeat.

4. Quantitative Sensitivity and Constraints

4.1 Sensitivity Limits

A hallmark of rigorous analysis is quantifying sensitivity limits. In a recent 30-minute COSMIC experiment covering 511 sources, the minimum detectable EIRP ranged from ~2.3×10^11 W for the nearest stars (~4.3 pc) to ~10^13 W at mid-range distances (~100 pc), and up to ~2.1×10^16 W for distant stars (~1,300 pc).

To put these thresholds in practical context: an Arecibo-class radar (2×10^13 W EIRP) would produce a strong 8σ signal at ~4 pc but would be over 1000× too weak to detect at ~1,300 pc. COSMIC is sensitive to Kardashev Type I transmitters (10^16 W) out to kiloparsec distances, and can detect more modest power levels (10^12–10^13 W, comparable to powerful terrestrial radars) out to tens of parsecs.

4.2 Statistical Implications of Null Results

Using Poisson statistics for null detection at 95% confidence, if 0 out of N stars show signals, at most ~3/N could have detectable transmitters. For N = 10^6 examined stars, this yields an upper limit of ~3×10^–6, meaning fewer than a few in a million stars could be broadcasting strong radio beacons at the surveyed frequencies and power levels.

Important caveats apply: these limits address only constant, powerful transmitters. Weaker or intermittent signals could remain undetected, and sensitivity varies across the surveyed spectrum—currently best in the 2–4 GHz range, with reduced sensitivity at higher frequencies extending up to 50 GHz.

4.3 False Positive Management

The pipeline employs an SNR threshold of 8 and searches for drift rates up to 50 Hz/s via TurboSETI/seticore, applying multiple signal-selection criteria to manage false positives. However, this filtering carries the risk of discarding true signals that fall at search boundaries—for instance, signals with drift rates just outside the search range or SNR values of 7.5.

A comprehensive completeness analysis is needed to quantify detection efficiency and false-alarm probability across parameter space, enabling statements like "90% complete for transmitters stronger than X W out to Y light years." Such rigor is essential for interpreting null results and planning future observations.

5. Interdisciplinary Integration: AI and Robotics

5.1 Machine Learning for Signal Classification

Breakthrough Listen has pioneered the application of neural networks and autoencoders to SETI data, using a "reverse image search" approach to find unusual signal clusters and discovering candidate signals that traditional algorithms missed. COSMIC's millions of detections per hour make it an ideal testbed for further ML assistance.

Currently, COSMIC relies on rule-based filters followed by human inspection, but the path forward involves deep learning for automated RFI rejection. Autoencoders could learn the latent features distinguishing RFI from hypothetical technosignatures, dramatically reducing the manual review burden while potentially improving sensitivity to anomalous patterns.

5.2 Reinforcement Learning for Optimization

Reinforcement learning agents have demonstrated the ability to autonomously adjust pipeline hyperparameters, achieving efficiency improvements without human intervention. This "digital co-pilot" concept could revolutionize real-time instrument tuning for facilities like COSMIC.

Potential applications include dynamic threshold adjustment responding to changing RFI conditions, automated follow-up observation suggestions prioritizing the most promising candidates, continuous learning to better distinguish RFI from genuine signals, and optimization of the entire data processing flow to maximize throughput and sensitivity.

5.3 Robotics in Telescope Calibration

Brookhaven National Lab and Yale University have pioneered drone-based calibration, using quadcopter drones carrying reference transmitters to map beam patterns by comparing GPS track to received signals. This enables precise measurement of telescope response across the array.

However, significant technical challenges remain. Position precision requires ~1 cm GPS accuracy (achievable only with differential GPS solutions), flight stability proves difficult to maintain in practice, regulatory constraints complicate flying drones over large antenna fields, and repeated measurements demand fully autonomous flight capabilities. Fixed-wing drones offer an alternative approach—faster, capable of longer flights, and better at revisiting precise coordinates—but sacrifice hovering capability, trading speed for maneuverability.

5.4 Critical Assessment

For claims about "AI integration" to be rigorous, we need quantifiable improvements ("0.1% calibration accuracy vs 1% traditional methods") and proper benchmarking ("RL-based scheduler improved sensitivity by X%"). A fundamental limitation is the lack of confirmed alien signals for supervised learning, making unsupervised methods and anomaly detection more appropriate approaches.

The current status represents a promising frontier, but we remain in early days. Comprehensive benchmarking is essential, and practical challenges around precision, regulatory compliance, and interference mitigation must be systematically addressed before these technologies become routine components of SETI infrastructure.

6. Complementary SETI Strategy

6.1 COSMIC and Breakthrough Listen Synergy

Rather than competition, these initiatives form complementary strategies that together cover more parameter space than either could alone. COSMIC brings breadth of coverage through continuous observation with multiple simultaneous beams, excelling at detecting strong transmitters across vast sky regions. Breakthrough Listen contributes targeted depth through multi-wavelength searches spanning optical, laser, and fast radio burst detection, with immediate follow-up capability enabled by dedicated observation time. The synergy is clear: COSMIC's wide net catches what BL might miss through limited sky coverage, while BL's deep stares detect faint signals that COSMIC's brief exposures would not register.

6.2 Global Network Coordination

An emerging global infrastructure is taking shape: COSMIC at the VLA, Breakthrough Listen deployments at MeerKAT in South Africa plus Green Bank and Parkes, China's FAST telescope, and future facilities including the next-generation VLA and the Square Kilometre Array. This distributed network serves a critical function beyond increasing search volume—it enables independent verification.

The verification protocol is unambiguous: no single detection is considered valid until independently confirmed by another facility. Cross-facility verification serves as the gold standard, making rapid follow-up agreements between institutions absolutely critical. When COSMIC or any facility detects a candidate signal, the ability to immediately request confirmation observations from geographically separated telescopes distinguishes genuine discoveries from artifacts.

7. Future Directions and Challenges

7.1 Technical Roadmap

COSMIC's evolution will expand frequency coverage to 50 GHz, integrate real-time machine learning classifiers, implement enhanced calibration protocols, and deploy fully automated data reduction pipelines. Each advancement addresses current limitations while preparing for the next generation of radio astronomy.

The big data challenge looms large: next-generation facilities like ngVLA and SKA will produce torrents of data that will utterly overwhelm current human analysis capacity. New post-processing methods are not merely desirable—they are essential for these facilities to fulfill their scientific potential. COSMIC serves as a vital testbed for developing and validating the algorithms, workflows, and infrastructure needed to handle astronomical "big data" at unprecedented scales.

7.2 Theoretical Considerations

The Cosmic Haystack:

Current searches sample only a tiny portion of the vast parameter space available for potential technosignatures. We observe within limited time windows, across narrow frequency ranges, and only a small fraction of the sky receives deep exposure. This sampling limitation means our null results, while informative, cannot rule out civilizations operating outside these search constraints.

Alternative Technosignature Types:

Beyond radio signals, other possibilities remain largely unexplored: optical laser pulses could serve as interstellar beacons, stellar dimming patterns might reveal megastructures like Dyson spheres, unconventional modulation schemes could evade our current detection algorithms, and entirely novel technologies beyond current imagination may exist that we lack the frameworks to even consider.

7.3 Statistical and Philosophical Implications

Current Constraints Suggest:

The null results to date suggest three non-exclusive possibilities: powerful transmitters may be extremely rare in our galactic neighborhood, civilizations may deliberately avoid using easily detectable beacons (perhaps for stealth or energy efficiency), or they employ communication technologies so advanced that we cannot yet recognize them as artificial.

Note of Humility:

It's crucial to remember that we've sampled only a tiny fraction of our galaxy, over a limited time window and narrow frequency range. The true discovery that would transform our understanding of our place in the cosmos could await just beyond our current observational limits.

8. Conclusion

COSMIC represents a significant advancement in SETI capability, demonstrating how commensal observing and modern computing can dramatically scale the search for extraterrestrial intelligence. Its achievements in the first year of operation - surveying nearly a million fields and setting stringent new constraints on transmitter prevalence - validate the commensal approach.

However, critical analysis reveals important limitations: lack of target control, dependence on VLA scheduling, challenges in RFI discrimination, and delayed follow-up capability. These are not fatal flaws but rather design trade-offs that complement other search strategies, particularly Breakthrough Listen's targeted depth.

The integration of AI and robotics offers promising but not yet mature enhancements. Machine learning can assist in signal classification and instrument optimization, while robotic systems may improve calibration precision. Yet these technologies require rigorous benchmarking and face practical challenges before becoming routine.

Most importantly, COSMIC's null results to date reinforce a sobering reality: either technologically advanced civilizations with powerful beacons are exceedingly rare, or our search strategies miss their signals. The cosmic haystack remains vast, and we have barely begun to search it systematically.

As COSMIC expands its frequency coverage, as complementary facilities come online, and as analysis techniques mature, the probability of detection improves incrementally. But as the pioneers of SETI noted: "The probability of success may be difficult to estimate; but if we never search, the chance of success is zero." COSMIC ensures we continue searching - with unprecedented scale, sensitivity, and scientific rigor.

References

1. COSMIC project description, SETI Institute - https://www.seti.org/projects/cosmic/
2. Tremblay et al. 2025, Astronomical Journal - COSMIC Survey Description & First Results - https://arxiv.org/html/2501.17997v1
3. Croft & Lee 2023, Supercluster - "SETI Deploys New Instruments..." - https://www.supercluster.com/editorial/seti-deploys-new-instruments-in-search-for-alien-intelligence
4. Cowing, K. 2023, Astrobiology.com - "The Very Large Array Will Search For Signals From Extraterrestrial Civilizations" - https://astrobiology.com/2023/05/the-very-large-array-will-search-for-signals-from-extraterrestrial-civilizations.html
5. Hrinko, I. 2024, Universe Magazine - "SETI starts the most extensive search for aliens in history" - https://universemagazine.com/en/seti-starts-the-most-extensive-search-for-aliens-in-history/
6. Garrett & Siemion 2022 - "Constraints On Extragalactic Transmitters Via Breakthrough Listen" - https://astrobiology.com/2022/09/constraints-on-extragalactic-transmitters-via-breakthrough-listen.html
7. Yatawatta & Avruch 2021, MNRAS - "Deep reinforcement learning for smart calibration of radio telescopes" - https://arxiv.org/abs/2102.03200
8. Brookhaven National Laboratory 2020 - "Drones Help Calibrate Radio Telescope at Brookhaven Lab" - https://www.bnl.gov/newsroom/news.php?a=217118

Acknowledgments

This analysis synthesizes findings from the COSMIC team at the SETI Institute, the Breakthrough Listen Initiative at UC Berkeley, and various international collaborators in radio astronomy and SETI research. Special recognition to the VLA operations team for enabling commensal observing mode.