PTYS/LPL Faculty

Robert McMillan


  • Chet Maleszewski (PTYS)


  • William Merline, 1995 (PTYS)


  • Robert Jedicke
  • Jeffrey Larsen
  • David Rabinowitz
Bob McMillan
Associate Research Scientist
Asteroid surveys, Spacewatch, Planetary astronomy
Ph.D., 1977, University of Texas at Austin

Kuiper   #225

Years with LPL:  1979 to present


Dr. McMillan is in charge of the Spacewatch survey of the solar system for near-Earth asteroids, main-belt asteroids, Centaurs, comets, and Trans-Neptunian objects. He is also a Co-Investigator on the Science Team of the Wide-field Infrared Survey Explorer (WISE) spacecraft mission that completed its infrared survey of the whole sky with multiple passes. His roles for that mission include ground-based followup observations of asteroids and comets discovered by WISE, leader of the solar system working group of the WISE mission, and Cognizant Scientist for initial boresight alignment of the Attitude Determination and Control System with the science detectors of the spacecraft. In 2010 during the flight phase of the mission, McMillan's Spacewatch team contributed more recovery observations, by a factor of 2, of Near-Earth Objects recently discovered by WISE than any other asteroid followup station.

McMillan's career has included studies of variable stars, statistics of stellar populations, interstellar dust, interstellar magnetic fields, planetary atmospheres, Doppler shift spectroscopy of stars, astronomical instrumentation, and surveys of asteroids. He has worked in the last four disciplines from 1979 to the present while at the Lunar and Planetary Laboratory at the University of Arizona.

McMillan's group at LPL was the first to publish stellar Doppler shift (radial velocity; RV) measurements better than +/-20 meters per second (m/s) in a refereed journal. They also made the first reliable detection of p-mode oscillations in a star other than the Sun (Arcturus), discovered the spectroscopic binary of then-longest known period, and established a new upper limit on the RV stability of the Sun observed as a point source. That limit was published in 1993 and as of 2011 has been neither challenged nor surpassed. McMillan also further investigated techniques to measure the RVs of stars in ways that minimize contamination of Doppler shift measurements by effects intrinsic to stellar atmospheres. He returned to the field in 2007 as a collaborator with a group from the U. S. Naval Observatory who used a prototype of a newly designed dispersed Fourier Transform Spectrometer to measure the RVs of binary stars with the 2.3-meter Bok Telescope of the Steward Observatory.

As Co-Investigator and Project Scientist of Prof. Tom Gehrels' Spacewatch Project, McMillan guided the physical realization of CCD surveying as a productive method of exploring the solar system for asteroids and comets. McMillan became the Principal Investigator of Spacewatch in mid-1997. In 2000 McMillan discovered large Trans-Neptunian Object 2000 WR106, now known as Minor Planet (20000) Varuna. The 1.8-m telescope was completed and the 0.9-m was completely rebuilt with all new optics and detectors under McMillan's leadership, and the 0.9-m scope was fully automated in 2006. Spacewatch makes more observations of potentially hazardous asteroids while they are distant and faint than any other group.

CV for Dr. McMillan (PDF)


  • Spacewatch Project: Grants from NASA Near-Earth Object Observation Program
  • Asteroid Research funded by the Brinson Foundation of Chicago, IL


Wide-field Infrared Survey Explorer mission
Near-Earth Object Camera
Principal Investigator of Spacewatch (ground-based)


Pioneer 11/Saturn (1979-1980)


Selected Publications with RSM as major contributor, in chronological order:

Near-Infrared Photometry of Selected IRC Objects, 1971, G. W. Lockwood and RSM, Late-Type Stars, Proceedings of a Conference held in Tucson, AZ, October, 1970. Ed. G. W. Lockwood and H. M. Dyck. Kitt Peak National Observatory, Contribution No. 554, 1971, p.171.

"Mean Absolute Magnitudes of Selected Spectral Groups", 1973, S. W. McCuskey and RSM, AJ 78, 73

"A Survey for Small Amplitude Variability Among Population II Stars", 1976, RSM, M. Breger, G. J. Ferland, and G. L. Loumos, PASP 88, 495:

"Interstellar Polarization in Front of the Young Cluster NGC 7380", 1976, RSM, AJ 81, 970:

"The Wavelength Dependence of Polarization in the Cygnus OB2 Association: A New Determination of Interstellar Birefringence", 1977, RSM and S. Tapia, ApJ 212, 714:

"Walker No. 67 in NGC 2264: A Candidate for Strong Interstellar Circular Polarization", 1977, RSM, ApJLett 216, L41:

"Are Long Wavelengths of Maximum Interstellar Polarization Due to Water Ice Mantles on Grains?" 1978, RSM, ApJ 225, 417:

"Predicted Color Excess Ratios Versus Interstellar Grain Size", 1978, RSM, ApJ 225,

"Discovery of Polarized Light Scattered by Dust Around Alpha Orionis", 1978, RSM and S.Tapia, ApJLett 226, L87:

"An Upper Limit on Ultraviolet Shot Noise from Cygnus X 1", 1979, J. G. Duthie and RSM, ApJ 232, 255:

"Photometry of Saturn at Large Phase Angles", 1980, M. G. Tomasko, L. R. Doose, N. D. Castillo, RSM, and J. P. Dilley, J. Geophys. Res. 85, 5891.

"Software Simulations of the Detection of Rapidly Moving Asteroids by a Charge Coupled Device", 1982, RSM and C. P. Stoll, Proc. SPIE 331, 104-112.

"A CCD System for Photometry of Direct and Spectroscopic Images", 1984, J. E. Frecker, T. Gehrels, RSM, W. J. Merline, M. L. Perry, J. V. Scotti, and P. H. Smith, in Proc. of the Workshop on Improvements in Photometry, ed. W. J. Borucki and A. Young, NASA CP 2350, pp. 137 151.

"The LPL Radial Accelerometer," 1985, R. S. McMillan, P. H. Smith, J. E. Frecker, W. J. Merline, and M. L. Perry, in Proc. of IAU Colloq. No. 88, Stellar Radial Velocities, A.G. Davis Philip and D. W. Latham, eds. (New York: L. Davis Press), pp. 63-86.

"A Fabry-Perot Interferometer for Accurate Measurement of Temporal Changes in Stellar Doppler Shift", 1986, RSM, P. H. Smith, J. E. Frecker, W. J. Merline, and M. L. Perry, in Proc. SPIE 627, Instrumentation in Astronomy-VI, ed. D. L. Crawford, pp. 2-19.

"Use of a Scanning CCD to Discriminate Asteroid Images Moving in a Field of Stars", 1986, RSM, J. V. Scotti, J. E. Frecker, T. Gehrels, and M. L. Perry, in Proc. SPIE 627, Instrumentation in Astronomy VI, ed. D. L. Crawford, pp. 141 154.

"Astrometry with a Scanning CCD", 1986, T. Gehrels, B. G. Marsden, RSM, and J. V. Scotti, AJ 91, 1242.

"Evidence for Periodic Radial Velocity Variations in Arcturus", 1987, P. H. Smith, RSM, and W. J. Merline, ApJLett 317, L79:

"Non variability of the Radial Velocity of Eta Cas A," 1987, RSM and P. H. Smith, PASP 99, 849:

"Differential CCD Photometry of Faint Asteroids in Crowded Star Fields and Non photometric Sky Conditions", 1987, W. Z. Wisniewski and RSM, AJ 93, 1264 1267.

"The Optical Fiber Feed of the LPL Radial Velocity Spectrometer", 1988, RSM, M. L. Perry, P. H. Smith,and W. J. Merline, A. S. P. Conf. Ser. 3, Fiber Optics in Astronomy, ed. S. C. Barden, (San Francisco: A. S. P.), 237-246.

"A Survey for Doppler-Shift Oscillations in K Giants", 1988, P. H. Smith, R. S. McMillan, and W. J. Merline, in Proc. IAU Symp. 123, Helio-and Astero-seismology Dordrecht: Reidel), 277-280:

"Short Period Oscillations in Alpha Boo, Beta Gem, and Alpha Tau", 1988, P. H. Smith and R. S. McMillan, in Proc. IAU Symp. 132: The Impact of Very High S/N Spectroscopy on Stellar Physics (Dordrecht: Reidel), 291-294:

"Long-Term Stability of a Fabry-Perot Interferometer Used for Measurement of Stellar Doppler Shift", 1990, RSM, P. H. Smith, M. L. Perry, T. L. Moore, and W. J. Merline, in Instrumentation in Astronomy VII, Proc. SPIE 1235, ed. D. L. Crawford, 601-609:

"Variation of the Radial Velocity of Epsilon Cygni A", 1992, RSM, P. H. Smith, T. L. Moore, and M. L. Perry, PASP 104, 1173:

"Discussion of Thermal Specs of Ronchi Rulings", 1992, by R. S. McMillan, in Astrometric Imaging Telescope 1991 Final Report, JPL D-9651 (Pasadena: JPL/Cal Tech), ed. S. H. Pravdo, 129-133.

"Overview of Temperature Specs on CCD used as a Metric for AIT", 1993, by R. S. McMillan, in Astrometric Imaging Telescope 1992 Final Report, JPL D-10760 (Pasadena: JPL/Cal Tech), ed. S. H. Pravdo, 377.

"Radial Velocity Observations of the Sun at Night", 1993, RSM, T. L. Moore, M. L. Perry, and P. H. Smith, ApJ 403, 801-809:

"Long, Accurate Time Series Measurements of Radial Velocities of Solar-Type Stars", 1994, RSM, T. L. Moore, M. L. Perry, & P. H. Smith, Astrophys. & Space Sci., 212, 271-280:

"Charge-coupled Devices", 1997, by RSM, in Encyclopedia of Planetary Science, J. H. Shirley & R. W. Fairbridge, Eds. London: Chapman and Hall, 98-102.

The Multichannel Astrometric Photometer with Spectrograph: A New Instrument for the Characterization of Extrasolar Planetary Systems, 1997, by G. D. Gatewood, D. Snyder Hale, W. T. Persinger, RSM, J. L. Montani, T. L. Moore, M. L. Perry, in Planets Beyond the Solar System and the Next Generation of Space Missions, ed. D. Soderblom, (San Francisco: A. S. P.), 119, 41-52.

Extrasolar Planets, 1997, by RSM, in The Encyclopedia of Planetary Science, J. H. Shirley & R. W. Fairbridge, Eds. (London: Chapman and Hall), 588-590.

"Photoelectric Observations of 125 Asteroids", 1997, W. Z. Wisniewski, T. M. Michalowski, A. W. Harris, and RSM, Icarus, 126, 395-449.

"The 1.8m Spacewatch telescope motion control system", 1998, M. L. Perry, T. H. Bressi, RSM, A. F. Tubbiolo, and L. D. Barr Proc. SPIE 3351, Telescope Control Systems III, 450-465:

"Exploration of Asteroid and Comet Populations", 1998, RSM, SSI Update - The High Frontier Newsletter, (Princeton, NJ: Space Studies Institute), 23, issue 5, pp1-2, 5-6.

The Value of Fabry-Perot Interferometry in Studying Long-Term Convective Line Shifts, 1999, by RSM, in IAU Colloquium 170: Precise Stellar Radial Velocities, ASP Conf. Series 185, 278-285:

"The Spacewatch search for material resources near Earth", 1999, RSM, In Space Manufacturing 12: Challenges and Opportunities in Space: Proceedings of the Fourteenth Space Studies Institute's Princeton Conference on Space Manufacturing, May 6-9, 1999, B. Greber, Ed. (SSI Publishing, Princeton, NJ), 72-75.

"Discovery and Confirmation of Asteroid (719) Albert = 2000 JW8", 2000, by J. A. Larsen, RSM, J. V. Scotti, M. Hicks, R. Fevig, and G. V. Williams, IAU Circ. 7420.

"Discovery of Trans-Neptunian Object 2000 WR106", 2000, by RSM and J. A. Larsen, Minor Planet Electronic Circ. 2000 X02:

"The Spacewatch wide area survey for bright Centaurs and Transneptunian objects", 2001, by J. A. Larsen, A. E. Gleason, N. M. Danzl, A. S. Descour, RSM, T. Gehrels, R. Jedicke, J.L. Montani, and J. V. Scotti, Astron. J., 121, 562-579:

A Study to Determine the Feasibility of Extending the Search for Near-Earth Objects to Smaller Limiting Diameters", 2003, G. H. Stokes, D. K. Yeomans, W. F. Bottke Jr., S. R. Chesley, J. B. Evans, R. E. Gold, A. W. Harris, D. Jewitt, T. S. Kelso, RSM, T. B. Spahr, and S. P. Worden. Report of the Near-Earth Object Science Definition Team

"Review of book entitled Mitigation of Hazardous Comets and Asteroids", 2005, R. S. McMillan, Meteoritics and Planetary Science, 40, 509:

"The Spacewatch Volunteer Search for Fast Moving Objects", 2005, by RSM, M. Block, and A. S. Descour. The ALP's Minor Planet Bulletin, 32, No. 3, page 53:

The Origins Billions Star Survey: Galactic Explorer, 2006, by K. J. Johnston et al. including RSM. PASP 118, 1428-1442.

The Search for Distant Objects in the Solar System using Spacewatch, 2007, by J. A. Larsen et al., AJ, 133, 1247-1270.

"Spacewatch Preparations for the Era of Deep All-sky Surveys", 2007, by RSM and the Spacewatch Team. In Proc. IAU Symp. 236: Near Earth Objects, our Celestial Neighbors Opportunity and Risk, A. Milani, G. Valsecchi, and D. Vokrouhlicky, Eds. (Cambridge U. Press), pp 329-340.

Initial Results from the USNO Dispersed Fourier Transform Spectrograph, 2007, by Hajian, A.R., and 17 co-authors including RSM. ApJ 661, 616-633.

Discovery Observations of Comet P/2008 U1 (McMillan), 2008, by RSM. IAU Circ. 8997.

Discovery Observations of Comet P/2008 U1 (McMillan), 2008, by RSM. Minor Planet Electronic Circ. 2008-U29:

Stellar Astrophysics with a Dispersed Fourier Transform Spectrograph. I. Instrument Description and Orbits of Single-lined Spectroscopic Binaries, 2009, by Behr, B. B., and six other authors including RSM. ApJ, 705, 543-553:

"The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance", 2010, by Wright, E. L., and 33 co-authors including RSM. AJ 140, 1868-1881.

Preliminary Results from NEOWISE: An Enhancement to the Wide-field Infrared Survey Explorer for Solar System Science, 2011, by Mainzer, A. and 34 co-authors including RSM. ApJ 731, Issue 1, article id. 53:

"Stellar Astrophysics with a Dispersed Fourier Transform Spectrograph. II. Orbits of Double-lined Spectroscopic Binaries", 2011, by Behr, B. B., and 6 co-authors including RSM. AJ 142, Issue 1, article id. 6:

"Thermal Model Calibration for Minor Planets Observed with Wide-field Infrared Survey Explorer/NEOWISE", 2011, by Mainzer, A. and 9 co-authors including RSM. ApJ 736, Issue 2, article id. 100

"Thermal Model Calibration for Minor Planets Observed with WISE/NEOWISE: Comparison with Infrared Astronomical Satellite", 2011, by Mainzer, A., and 7 co-authors including RSM. ApJ Lett 737, Issue 1, article id. L9

"WISE/NEOWISE Observations of Comet 103P/Hartley 2", 2011, by Bauer, J. M., and 20 named co-authors including RSM. ApJ 738, Issue 2, article id. 171

"WISE/NEOWISE Observations of the Hilda Population: Preliminary Results", 2011, by Grav, T., and 16 co-authors including RSM. ApJ, accepted

"Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters", 2011, by Masiero, J. R., and 17 co-authors including RSM. ApJ 741, Issue 2, article id. 68

"NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results", 2011, by Mainzer, A. K. and 12 co-authors including RSM. ApJ 741, Issue 2, article id. 90

"WISE/NEOWISE Observations of the Jovian Trojans: Preliminary Results", 2011, by Grav, T. and 16 co-authors including RSM

"WISE/NEOWISE observations of Active Bodies in the Main Belt", 2011, by Bauer, J. M., and 23 named co-authors including RSM

"NEOWISE Studies of Asteroids with Sloan Photometry: Preliminary Results", 2012, by Mainzer, A., and 13 co-authors including RSM. ApJ 745, Issue 1, article id. 7

"Characterizing Subpopulations within the near-Earth Objects with NEOWISE: Preliminary Results", by Mainzer, A., and 12 co-authors including RSM. ApJ 752, Issue 2, article id. 110

"Physical Parameters of Asteroids Estimated from the WISE
3-Band Data and NEOWISE Post-Cryogenic Survey", 2012, by
Mainzer, A., and 9 co-authors including RSM. ApJ Issue 1, article id L12

Selected Abstracts:

McMillan, R. S. 1998. Applicability of the Spacewatch Telescopes to the Exploration of the Outer Solar System. Abstract of paper presented at the Kuiper Belt Workshop at Lowell Observatory, Sept. 2-5, 1998.

McMillan, R. S. 1999. Spacewatch discovery and study of accessible asteroids. Abstract of paper presented at the First Space Resources Roundtable at the Colorado School of Mines in Golden, CO: Lunar & Planetary Institute (Houston) Contrib. No. 988.

McMillan, R. S., M. L. Perry, T. H. Bressi, J. L. Montani, A. F. Tubbiolo, M. T. Read. 2000. Progress on the Spacewatch 1.8-m telescope and upgrade of the Spacewatch 0.9-m telescope. B. A. A. S. 32, 1042-1043:

Larsen, J. A., and the Spacewatch Team. 2005. The size distribution of small near-Earth asteroids from the Spacewatch Survey. B. A. A. S. 37, No. 4, abstract 4.09:

Roe, E. A, J. A. Larsen, and the Spacewatch Team. 2005. Search for the tenth planet: Testing inferences from the "Kuiper cliff". B. A. A. S. 37, No. 4, abstract 4.07:

McMillan, R. S., A. K. Mainzer, R. G. Walker, E. L. Wright, P. R. Eisenhardt, R. M. Cutri, T. Grav, and the WISE Science Team. 2009. NEOWISE: Proposed Discovery of Near-Earth Objects in the Infrared by the WISE Mission. Talk 459.06: abstract,and poster: B. A. A. S., 41, 364.

McMillan, R. S. 2009. Spacewatch Support of Deep Wide-Field NEO Surveys; White Paper submitted to NRC Committee to Review Near-Earth Object Surveys and Hazard Mitigation Strategies, and PDF format Powerpoint slide series to accompany presentation to the Committee on 2009 April 20.

McMillan, R. S., and the WISE Team. 2009. Abstract of WISE Solar System Science, talk presented at 214th Meeting of the American Astronomical Society, 2009 June 9, Presentation No. 217.02, and slides. B.A.A.S. 41,724.

McMillan, R. S., et al. 2010. Spacewatch Observations of Asteroids and Comets with Emphasis on Discoveries by WISE. AAS/DPS meeting #42, #13.22; BAAS 42, 1057:

McMillan, Robert S., and the WISE Team. 2011. Solar System Science with WISE. AAS Meeting #217, #301.03; BAAS 43, 2011:

"NEOWISE Observations of Near-Earth Objects: Preliminary Results", 2011, by Mainzer, A. K., and 36 co-authors including RSM. ApJ 743, Issue 2, article id. 156

"Spacewatch Observations of Near-Earth Objects", by McMillan, R. S., and 4 co-authors. AAS/Division for Planetary Sciences Meeting Abstracts,t#210.14

Robert S. McMillan has also co-authored 1,145 Minor Planet Electronic Circulars (MPECs) describing discoveries and followup astrometry of minor planets and comets, and contributed to hundreds more MPECs in Daily Orbital Updates from the Minor Planet Center without explicit author attribution. He has also co-authored 36 IAU Circulars, and dozens of other astronomical publications not listed above since 1971.