**FULL TITLE** ASP Conference Series, Vol. **VOLUME**, c **YEAR OF PUBLICATION** **NAMES OF EDITORS** Spin-Off Successes of SETI Research at Berkeley K. A. Douglas School of Physics, University of Exeter, Exeter, United Kingdom D. P. Anderson, R. Bankay, H. Chen, J. Cobb, E.J. Korpela, M. Lebofsky, A. Parsons, J. Von Korff, D. Werthimer Space Sciences Laboratory, University of California Berkeley, Berkeley CA, USA 94720 Abstract. Our group contributes to the Search for Extra-Terrestrial Intelligence (SETI) by developing and using world-class signal processing computers to analyze data collected on the Arecibo telescope. Although no patterned signal of extra-terrestrial origin has yet been detected, and the immediate prospects for making such a detection are highly uncertain, the SETI@home project has nonetheless proven the value of pursuing such research through its impact on the fields of distributed computing, real-time signal pro- cessing, and radio astronomy. The SETI@home project has spun off the Center for Astronomy Signal Processing and Electronics Research (CASPER) and the Berkeley Open Infrastructure for Networked Computing (BOINC), both of which are responsi- ble for catalyzing a smorgasbord of new research in scientific disciplines in countries around the world. Futhermore, the data collected and archived for the SETI@home project is proving valuable in data-mining experiments for mapping neutral galatic hy- drogen and for detecting black-hole evaporation. 1 The SETI@home Project at UC Berkeley SETI@home is a distributed computing project harnessing the power from millions of volunteer computers around the world (Anderson 2002). Data collected at the Arecibo radio telescope via commensal observations are filtered and calibrated using real-time signal processing hardware, and selectable channels are recorded to disk. These disks are shipped to UC Berkeley, where the data are distributed over the Internet in the form of “work units” to volunteers who use spare cycles on their computer to search for patterns in the recorded noise. Processed work units are returned to UC Berkeley and stored in databases for further statistical analysis in the search for signals indicative of extra-terrestrial intelligence. While the direct product of this research has been a series of null results, the technology developed for this project is widely applicable, and has spun off several derivative projects based around the real-time signal processing architecture used at the telescope (and other radio telescopes worldwide), the distributed computing archi- tecture used for off-line data processing, and the expansive archives of survey data collected for analysis. We illustrate the foundations of this research in the SETI@home project, and present several applications of the technology SETI@home has developed and generalized for widespread use. 1 2 Douglas et al. 2 The Center for Astronomy Signal Processing and Electronics Research In 2002, the SETI@home project submitted a proposal to the National Science Foun- dation to build a multipurpose signal processing board based on Field Programmable Gate Array (FPGA) processors that would be used to build a new SETI spectrome- ter at Arecibo, but would be flexible and reconfigurable for general radio astronomy use. The SERENDIP V processing board funded by this successful grant proposal was conscripted by more than 12 projects in applications ranging from pulsar timing sur- veys (Demorest et al. 2004) to interferometric correlation (Chippendale et al. 2005) to galactic hydrogen surveys (Heiles et al. 2004). The success of this project highlighted a need in the radio astronomy community for generic, commodity solutions for high- performance signal processing systems. Our expertise in correlator and spectrometer development and our experience in designing the SERENDIP V spectrometer let us to establish an offshoot group: the Center for Astronomy Signal Processing and Electron- ics Research (CASPER). The modular FPGA-based hardware and open-source signal processing libraries developed by CASPER (Parsons et al. 2006) are now being used for interferometry, beam-forming, spectroscopy, VLBI and pulsar timing at Arecibo, the Allen Telescope Array, GMRT (India), MeerKAT (South Africa), the Deep Space Network (NASA), Square Kilometer Prototype (Bologna), MIT/Haystack Observatory, Harvard/Smithsonian SMA, NRAO (Green Bank and the VLA), and the Precision Array for Probing the Epoch of Reionization (Australia). CASPER is currently developing a next-generation spectrometer for planetary missions that will orbit Mars, Venus and Earth: NASA’s MARVEL, VESPER and CAMEO sub-millimetre spectrometers. 3 The Berkeley Open Infrastructure for Network Computing As more volunteers joined the SETI@home distributed computing project, the Berke- ley Open Infrastructure for Network Computing (BOINC) was developed in order to make effective use of the increases in computing power and the diverse computational resources made available by SETI@home users. BOINC provides a non-commercial middleware system for volunteer computing, originally developed to support the SETI@home project, but intended to be useful for other applications in areas as diverse as mathemat- ics, medicine, molecular biology, climatology, and astrophysics. The intent of BOINC is to make it possible for researchers to tap into the enormous processing power of personal computers around the world (Anderson 2003). Today, BOINC users together comprise the world’s largest supercomputer. The BOINC project is a Berkeley-led and NSF-funded program which manages the top-level software common to over 40 distributed computing projects. BOINC projects include Einstein@home, a search for gravitational waves; protein folding with Rosetta@home; global climate modelling with Climateprediction.net; as well as HIV, cancer, and malaria drug research. Users are able to allocate fractions of their personal computing resources to any number of these projects, providing a valuable service to projects that might otherwise have been unable to afford access to the computing power necessary for their research. SETI@home Spin-offs 3 Projects Users Added Hosts Added Countries Total PFLOP/s Today Today FLOP Today SETI@Home 1,010,446 +362 2,418,560 +871 234 4.7 × 1027 8.0 MilkyWay@home 31,857 +119 69,363 +222 159 5.7 × 1025 5.9 World Community Grid 255,427 +217 777,876 +1,383 216 1.4 × 1026 3.3 Einstein@Home 236,724 +82 982,947 +976 211 1.2 × 1026 2.0 AQUA@home 6,738 +20 13,052 +32 114 1.2 × 1025 0.5 GPUGRID 5,584 +16 9,102 +29 93 3.0 × 1025 1.5 Climate Prediction 201,702 +114 390,945 +206 210 7.9 × 1025 0.8 Rosetta@Home 260,677 +164 778,085 +431 220 6.7 × 1025 0.9 PrimeGrid 26,420 +26 76,204 +72 158 1.2 × 1025 0.3 ABC@home 22,978 +23 63,054 +42 149 1.7 × 1025 0.2 Table 1. The 10 most popular volunteer computing projects using the BOINC infrastructure as of September 1, 2009 4 Data Mining Experiments with SETI@home Data While the main goal of the SETI@home project is to detect signals of extraterrestrial and intelligent origin, the data collected have been used for other scientific projects, including the mapping of neutral galactic hydrogen (SETHI), and searching for short- timescale bursting phenomena (AstroPulse). The 21-cm spectral line of neutral hydrogen (H I) is one of the best tracers of the Galaxy’s interstellar medium. The SETI@home spectrometer has been (non-uniformly) sampling the H I sky visible from Arecibo since 1999. Millions of spectra have been combined to create three-dimensional spectral emission “datacubes” covering 7200 square degrees of the sky (Douglas and Korpela 2009). AstroPulse is a distributed computing project fashioned after SETI@home. It will search for pulses of emission from pulsars, black holes, and other exotic objects that have been dispersed by the interstellar medium. More details are given in another articles in these proceedings (Von Korff et al. 2009). In July 2006 a new SETI@home data recorder was installed at Arecibo to per- form commensal observations with all observations done with the ALFA receiver. This multibeam system provides unprecedented sensitivity to weak celestial (and man-made) emission and greatly increases our data rate. These advances ensure that SETI@home will continue to lead the search for intelligent life beyond Earth for years to come. Acknowledgments. SETI@home runs largely on the donations of its many volun- teers. Without this support, the spin-off advances described in these proceedings would not have been possible. References Anderson, D. P., J. Cobb, E. Korpela, M. Lebofsky, D. Werthimer, “SETI@home: An Experiment in Public-Resource Computing,” in Communications of the ACM, Nov. 2002, Vol. 45 No. 11, pp. 56-61. Anderson, D. P., “Public Computing: Reconnecting People to Science,” presented at the Conference on Shared Knowledge and the Web, Residencia de Estudi- antes, Madrid, Spain, Nov. 17-19 2003. 4 Douglas et al. Chippendale A. P., R. Subrahmanyan, R. D. Ekers, “The Cosmological Reionization Experiment,” presented at New Techniques and Results in Low Frequency Astronomy, Hobart, Dec. 2005. Demorest, P., R. Ramachandran, D. Backer, R. Ferdman, I. Stairs, and D. Nice, “Precision Pulsar Timing and Gravity Waves: Recent Advances in Instrumentation,” in Bulletin of the American Astronomical Society, Dec. 2004, pp. 1598–+. Douglas, K. A., and Korpela, E. J. 2009, in preparation Heiles, C., J. Goldston, J. Mock, A. Parsons, S. Stanimirovic, and D. Werthimer, “GALFA Hardware and Calibration Techniques,” in Bulletin of the American Astronomical Society, Dec. 2004, pp. 1476–+. Parsons, A., D. Backer, C. Chang, D. Chapman, H. Chen, P. Crescini, C. de Jesus, C. Dick, P. Droz, D. MacMahon, K. Meder, J. Mock, V. Nagpal, B. Nikolic, A. Parsa, B. Richards, A. Siemion, J. Wawrzynek, D. Werthimer, and M. Wright, “PetaOp/Second FPGA Signal Processing for SETI and Radio Astronomy,” in Asilomar Conference on Signals and Systems, Pacific Grove, CA, Nov. 2006, pp.