Interplanetary crew dose estimates for worst case solar particle events based on historical data for the Carrington flare of 1859

Over the past two decades, hypothetical models of “worst-case” solar particle event (SPE) spectra have been proposed in order to place an upper bound on radiation doses to critical body organs of interplanetary crews on deep space missions. These event spectra are usually formulated using hypothetical extrapolations of space measurements for previous large events. Here we take a different approach. Recently reported analyses of ice core samples indicate that the Carrington flare of 1859 is the largest event observed in the past 500 years. These ice core data yield estimates of the proton fluence for energies greater than 30 MeV, but provide no other spectrum information. Assuming that the proton energy distribution for such an event is similar to that measured for other recent, large events, interplanetary crew doses are estimated for these hypothetical worst case SPE spectra. These estimated doses are life threatening unless substantial shielding is provided.     

Space visions from a new generation

Through experiences at the International Space University's 1995 Summer Session, the authors became aware of generational differences of opinion with regard to visions for future space activities. The faculty members had expansionary visions of space exploration and colonization, while the students, having grown up in a very different environment, had concerns which centered around using space to improve life on Earth. This paper addresses possible explanations for these different perspectives. The visions of this younger generation are those which will shape the space policy of the future and are even beginning to shape it today.     

Compressibility effects on dynamic stall

Dynamic stall delay of flow over airfoils rapidly pitching past the static stall angle has been studied by many scientists. However, the effect of compressibility on this dynamic stall behavior has been less comprehensively studied. This review presents a detailed assessment of research performed on this subject, including a historical review of work performed on both aircraft and helicopters, and offers insight into the impact of compressibility on the complex aerodynamic phenomenon known as dynamic stall. It also documents the major effect that compressibility can have on dynamic stall events, and the complete change of physics of the stall process that can occur as free-stream Mach number is increased.     

Atmospheric science on the Galileo mission

Observations from the ground and four fly-by spacecraft have provided initial reconnaissance of Jupiter's atmosphere. The Pioneer and Voyager data have raised new questions and underlined old ones about the basic state of the atmosphere and the processes determining the atmosphere's behavior. This paper discusses the main atmospheric science objectives which will be addressed by the Galileo (Orbiter and Probe) mission, organizing the discussion according to the required measurements of chemical composition, thermal structure, clouds, radiation budget, dynamics, upper atmosphere, and satellite atmospheres. Progress on the key questions will contribute not only to our knowledge of Jupiter's atmosphere but to a general understanding of atmospheric processes which will be valuable for helping us to understand the atmosphere and climate of the Earth.Realization of the atmospheric science objectives of the Galileo mission depends upon: (a) coordinated measurements from the entry probe and the orbiter; (b) global observations; and (c) observations over the range of time-scales needed to characterize the basic dynamical processes.The Atmospheres Working Group also includes: M. D. Allison, M. J. S. Belton, R. W. Boese, R. W. Carlson, C. R. Chapman, T. Encrenaz, V. R. Eshleman, P. J. Gierasch, C. W. Hord, H. T. Howard, L. J. Lanzerotti, H. B. Niemann, G. S. Orton, T. Owen, C. B. Pilcher, J. B. Pollack, B. Ragent, W. B. Rossow, A. Seiff, A. I. Stewart, P. H. Stone, F. W. Taylor, G. L. Tyler, U. von Zahn, and R. A. West.