Orbital Effects of a Time-Dependent Pioneer-Like Anomalous Acceleration
L. Iorio, Orbital Effects of a Time-Dependent Pioneer-Like Anomalous Acceleration, Modern Physics Letters A, vol. 27, no. 12, id. 1250071, 2012
We work out the impact that the recently determined time-dependent component of the
Pioneer Anomaly (PA), if... more
We work out the impact that the recently determined time-dependent component of the
Pioneer Anomaly (PA), if interpreted as an additional exotic acceleration of gravitational
origin with respect to the well-known PA-like constant one, may have on the orbital
motions of some planets of the solar system. By assuming that it points towards the
Sun, it turns out that both the semi-major axis a and the eccentricity e of the orbit of
a test particle would experience secular variations. For Saturn and Uranus, for which
modern data records cover at least one full orbital revolution, such predicted anomalies
are up to 2–3 orders of magnitude larger than the present-day accuracies in empirical
determinations of their orbital parameters from the usual orbit determination procedures
in which the PA was not modeled. Given the predicted huge sizes of such hypothetical
signatures, it is unlikely that their absence from the presently available processed data
can be attributable to an “absorption” for them in the estimated parameters caused by
the fact that they were not explicitly modeled. The magnitude of a constant PA-type
acceleration at 9.5 au cannot be larger than 9 × 10−15 m s−2 according to the latest
observational results for the perihelion precession of Saturn.
Dynamic characterization of a subscale solar sail using non-contacting excitation and sensing
by Kara Slade
Co-authored with W. K. Belvin, T. K. Tetlow, and V. Behun
Proceedings of 44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
In preparation for any future mission, solar sail components and subsystems will undergo ground testing to assess key... more In preparation for any future mission, solar sail components and subsystems will undergo ground testing to assess key parameters that influence the reliability and performance. Among the key measurements to be made in these ground tests is the dynamic response of the solar sail since this data will be used to avoid control structure interaction. This paper reports a viable ground test technique for gathering the needed dynamic response information. The measurement of vibration mode frequencies and shapes of two solar sail testbeds is presented. The influence of gravity and ambient air are shown through empirical data taken in both ambient and vacuum conditions.
How to Survive Lunar Night
by Ed Trollope
Co-authored with Stephan Ulamec, Jens Biele.
Published in Planetary and Space Science, December 2010
Copyright © 2010, Elsevier