Education History

  • B S Physics, Wilkes University
  • M S Physics, University of Delaware
  • Ph D Physics, Brandeis University

Work Experience

Principal Professional Staff, JHU Applied Physics Laboratory


1) Zhang, Y., Paxton, L.J., Schaefer, R., Swartz, W., (2022), Thermospheric conditions associated with the loss of 40 Starlink satellites, Space Weather, accepted.
2) Kil, H., Paxton, L. J., & Schaefer, R. K. (2022). Simultaneous detection of signatures of conjugate photoelectrons in the ionosphere and thermosphere. Journal of Geophysical Research: Space Physics, 127, e2021JA030121.
3) Yongliang Zhang, Larry J. Paxton, Robert Schaefer, (2022), Comments on “A new method to subtract dayglow for auroral observation of SSUSI in LBH ranges based on the improved AURIC” by Wang et al. (2021), Journal of Atmospheric and Solar-Terrestrial Physics, 229, 105833,
4) Yongliang Zhang, Larry J. Paxton, R. Schaefer, (2022) Thermospheric density enhancement and limb O 130.4 nm radiance increase during geomagnetic storms Journal of Atmospheric and Solar-Terrestrial Physics, 229, 105830,
5) Zhang, Y., Paxton, L. J., & Schaefer, R. (2021). Ionospheric and thermospheric contributions in TIMED/GUVI O 135.6 nm radiances. Journal of Geophysical Research: Space Physics, 126, e2021JA029333.
6) Chartier, A. T., Datta-Barua, S., McDonald, S. E., Bust, G. S., Tate, J., Goncharenko, L. P., et al. (2021). Night-time ionospheric localized enhancements (NILE) observed in North America following geomagnetic disturbances. Journal of Geophysical Research: Space Physics, 126, e2021JA029324.
7) Paxton, L.J., Zhang, Y., Kil, H. and Schaefer, R.K. (2021). Exploring the Upper Atmosphere. In Upper Atmosphere Dynamics and Energetics (eds W. Wang, Y. Zhang and L.J. Paxton).
8) Zhang, Y, Paxton, L.J., Schaefer, R. 2020, Estimation of solar EUV flux from TIMED/GUVI data, J. Atm. Solar-Terr. Physics, 202, 105258 DOI: 10.1016/j.jastp.2020.105258.
9) Kil, H., Schaefer, R., Paxton, L.J., and Jee, G., 2020, The Far Ultraviolet Signatures of Conjugate Photoelectrons Seen by the Special Sensor Ultraviolet Spectrographic Imager, GRL, 47, 1., DOI: 10.1029/2019GL086383.
10) Zhang, Y, Paxton, L.J., Schaefer, R. 2019, Deriving thermospheric temperature from TIMED/GUVI observations, Jour. Geophys. Res. Space. Phys., 124, DOI: 10.1029/2018JA026379.
11) Paxton, Larry, Robert K. Schaefer, Yongliang Zhang, Hyosub Kil, and John E. Hicks, 2018, “SSUSI and SSUSI-Lite: Providing Space Situational Awareness and Support for Over 25 Years”, Johns Hopkins APL Technical Digest, 34, 3, 388-400.
12) Zhang, Y, Paxton, L.J., Morrison, D., Schaefer, R. 2018, Storm-time variations of atomic nitrogen 149.3 nm emission, Jour. Atmos. Solar Terr. Phys., 169, 78-82, DOI: 10.1016/j.jastp.2018.01.023.
13) Paxton, L. J., R. K. Schaefer, Y. Zhang, and H. Kil (2017), Far ultraviolet instrument technology, J. Geophys. Res. Space Physics, 122, 2706–2733, doi:10.1002/2016JA023578.
14) Hei, M. A., S. A. Budzien, K. F. Dymond, A. C. Nicholas, L. J. Paxton, R. K. Schaefer, and K. M. Groves (2017), Ionospheric-thermospheric UV tomography: 3. A multisensor technique for creating full-orbit reconstructions of atmospheric UV emission, Radio Sci., 52, 896–916, doi:10.1002/2015RS005887.
15) Schaefer, R.K., L.J. Paxton, C. Selby, B. Ogorzalek, G. Romeo, B. Wolven, and S.Y. Hsieh, (2016), Observation and modeling of the South Atlantic Anomaly in low Earth orbit using photometric instrument data, Space Weather, 14, doi:10.1002/2016SW001371.
16) T. Miller, R. Schaefer, and H. B. Sequiera, (2012), “PRIDE (Passive Radio [frequency] Ice Depth Experiment): An instrument to passively measure ice depth from a Europan orbiter using neutrinos”. Icarus 220, 877–888
17) S. B. Strong, L. J. Paxton, A. Kaushiva, M. Nix, W. H. Swartz, M. B. Weiss, R. Schaefer, (2012), The Global Assimilation of Information for Action (GAIA) Initiative: Understanding the Impact of Climate Change on National Security and Public Health. Proceedings of SPIE – The International Society for Optical Engineering 05/2012; 8371:14-. DOI:10.1117/12.919412
18) J. Holm, L. Paxton, M. Weiss, R. Schaefer, A. Rogers, A, Darrin, 2009, “Small Space Weather Satellites As A Component Of A Space Situational Awareness Virtual Organization”, Proceedings of the IAC, Daejun, Korea, Curran Associates, Red Hook, NY, USA
20) T. H. Burnett, et al., 2002, “Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Data Handling Overview”, IEEE Trans.Nucl.Sci. 49, 1904, (2002)
21) D. Thompson et al., 2002, “Gamma-ray Large Area Space Telescope Balloon Flight Engineering Model: Overview”, IEEE Transactions on Nucl. Sc., 49, 1898.
22) G. Romeo, S. Ali, B. Femenía, M. Limon, L. Piccirillo, R. Rebolo, & R. K.Schaefer, “Millimetric Ground-Based Observation of Cosmic Microwave Background Radiation Anisotropy at declination=+28°“, ApJL, 548, L1, (2001).
23) T.K. Gaisser & R.K. Schaefer, “Theoretical Predictions of Cosmic Ray Antiprotons”, Advances in Space Res., 19, 775, (1997).
24) S. Ali, M. Limon, L. Piccirillo, & R. K. Schaefer, “A Search for Microwave
Emission from Gamma Ray Bursts”, Astrophys. J., 487, 114, (1997).
25) R. Rebolo, B. Femeni’ a, L. Piccirillo, N. Kachwala, M. Limon, M. Guti’errez, J. Nichols, R.A. Watson, and R. K. Schaefer, “Millimetric Observations of CMB Anisotropy from Tenerife”, Anisotropies Du Ciel Micro-onde 4 (1997): 123.
26) G. Lazarides, R.K. Schaefer, and Q. Shafi, “Supersymmetric Inflation With
Constraints on Superheavy Neutrino Masses” Phys. Rev. D. 56, 1324, (1997).
27) Q. Shafi and R.K. Schaefer, “The Cold Plus Hot Dark Matter Model From
Supersymmetric Inflation”, Proc. of the 1996 Dark Matter Meeting, Heidelberg,
Germany, (1998).
28) T.K. Gaisser & R.K. Schaefer, “Theoretical Predictions of Cosmic Ray Antiprotons”,
Advances in Space Res., 11, 775, (1997).
29) L. Piccirillo, B. Femeni’ a, N. Kachwala, R. Rebolo, M. Limon, C.M. Guti’errez, J.
Nichols, R. K. Schaefer, R.A. Watson, “Millimetric ground-based observations of
Cosmic Microwave Background Anisotropy”, Astrophys. J. Lett. 475, 77, (1997).
30) T. Stanev, R. K.Schaefer, and A. Watson, “A Study of the Correlation Between Gamma Ray Bursts and the Highest Energy Cosmic Rays”, Astroparticle Phys., 5, 75, (1996).
31) A. R. Liddle, D.H. Lyth, R.K. Schaefer, Q. Shafi, and P. Viana, “Pursuing Parameters for Critical Density Dark Matter Models.”, Mon. Not. Roy. Ast. Soc., 281, 531, (1996).
32) R.K. Schaefer and A. de Laix, “Gauge Invariant Temperature and Density Perturbations in the Quasi-Newtonian Formulation”, Astrophys. J. Suppl., 105, 1, (1996).
33) K.S. Babu, Q. Shafi, and R.K. Schaefer, “Cold Plus Hot Dark Matter Cosmology in the Light of Solar and Atmospheric Neutrino Oscillations” Phys. Rev. D, 53, 606, (1996).
34) R.K. Schaefer, L. Piccirillo, “Optimizing Observing Strategies in Cosmic Microwave Background Experiments”, Astrophys. J., 461, 553, (1996).
35) M.S. Kowitt, et al., “The MSAM/TopHat program of Anisotropy Measurements”, Astrop. Lett. & Comm., 32, 273, (1995).
36) A.A. de Laix, R. J. Scherrer, R.K. Schaefer, “Constraints on Self–Interacting Dark Matter”, Astrophys. J., 452, 495, (1995).
37) R.K. Schaefer, S. Ali, M. Limon, L. Piccirillo, “COBE Observations of the Microwave Counterparts of Gamma Ray Bursts”, Astrophys. and Space Sci., 231, 331, (1995).
38) R. J. Scherrer and R.K. Schaefer, “When Do Non-Gaussian Density Fields Produce a Gaussian Sachs-Wolfe Effect?”. Astrophys. J., 446, 44, (1995).
39) G. Dvali, Q. Shafi, & R. K. Schaefer, “Large Scale Structure and Supersymmetric Inflation Without Fine Tuning”. Phys. Rev. Lett., 73, 1886, (1994).
40) R.K. Schaefer and Q. Shafi, “A Simple Model of Large Scale Structure Formation”, Phys. Rev. D, 49, 4990, (1994).
41) M. Subbarao, A. Szalay, R. K. Schaefer, S. Gulkis, and P. von Gronefeld, “Microwave Background Fluctuations Due to the Sunyaev-Zeldovich Effect in Pancakes”. Astrophys. J., 420, 474, (1994).
42) R.K. Schaefer, T.K. Gaisser, and T.S. Stanev, “Calculated Electron Fluxes at Airplane Altitudes”, Phys. Rev. D, 47, R4823, (1993).
43) R.K. Schaefer and Q. Shafi, “Inflation and Large Scale Structure Formation After COBE”, Phys. Rev. D, 47, 1333, (1993).
44) R.K. Schaefer, T.K.Gaisser, T.S. Stanev, and J. Petrakis, “Constraints on the Primary Nucleonic Cosmic Ray Spectrum From Atmospheric Electrons”, Proceedings of the Int. Conf. Cosmic Rays, Calgary, (refereed), (1993).
45) R.K. Schaefer and Q. Shafi, “Evidence For Some Hot Dark Matter?” Nature, 359, 199, (1992).
46) R.K. Schaefer, “Post-Modern Cosmology Basics”, lectures given at the ICTP, Summer School on Cosmology and Particle Physics”, E. Gava et al., eds., World Scientific, Singapore, (1992).
47) A. van Dalen and R. K. Schaefer, “Large Scale Structure Formation in a Cold Plus Hot Dark Matter Universe”, Astrophys. Jour., 398, 33, (1992).
48) T. K. Gaisser and R. K. Schaefer, “Cosmic Ray Secondary Antiprotons: A Closer Look”, Astrophys. Jour., 394, 174, (1992).
49) R. Schaefer, “Inflation, Large Scale Structure, and COBE’s DMR” in After the First Three Minutes, AIP conf. 222, S.S. Holt, C.L. Bennett, and V. Trimble, eds., American Inst. Phys. Press, New York, 1991.
50) R. Schaefer, “Gauge Invariant Fluid Description of Density Fluctuations of Collisionless Particles”, Int. Jour. Mod. Phys., A, 6, 2075, (1991).
51) R. Schaefer, “COBE and Inflation”, in Physical Cosmology, IInd Recontres de Blois, A. Blanchard, L. Celnikier, M. Lachieze-Rey, and J. Tran Than Van, eds. Editions Frontieres, Gif-sur-Yvette, Cedex, 1991.
52) G. Lazarides, R. Schaefer, D. Seckel, and Q. Shafi, “Dilution of Cosmological Axions Through Entropy Production” Nucl. Phys. B., 346, 393, (1990).
53) R. Schaefer, Q. Shafi, and F. W. Stecker, “Large Scale Structure and Cosmic Microwave Background Anisotropies in a Cold Plus Hot Dark Matter Universe”, Astrophys. Jour., 347, 575, (1989).
54) R. Schaefer, “Large Scale Structure Formation in a Cold Plus Hot Dark Matter Universe”, in Frontiers in Physics – From Colliders to Cosmology, A. Astbury, et al., eds., World Scientific, Singapore, (1989).
55) R. Schaefer, “Inhomogeneous Nucleosynthesis and the Cosmic Microwave Background Isotropy”, Phys. Rev D, 40, 271, (1989).
56) R. Schaefer, “Constraints on Baryonic Densities from the Cosmic Microwave Background Isotropy”, Proc. of “Cosmic Abundances of Matter”, Minneapolis, MN, August 15-17, (1988).
57) L. F. Abbott and R. K. Schaefer, “A General Gauge-Invariant Analysis of the Cosmic Microwave Anisotropy”, Astrophysical Jour., 308, 546, (1986).
58) L.F. Abbott, M.T. Grisaru, and R. K. Schaefer, “The Background Field Method and the S-Matrix”, Nucl. Phys., B229, 372, (1983).
59) S.P. Duggal, M.A. Pomerantz, R. K. Schaefer, and C.H. Tsao, “Cosmic Ray Modulations Related to the Interplanetary Magnetic Field Intensity”, Jour. Geophys. Res. 88, A4, 2973, (1983).

Professional Organizations