Binary Star System Decay by Graviton Interaction

The action of gravitons in a binary star system is modelled as the locus of points on an ellipse synchronous to the elliptic orbit of the binary star. In their interaction between the masses in the system the rotational energy of the gravitons is reduced by gravitational redshift, which accounts for the decay of the binary star orbital period. This model is able to fit a broad range of eccentricities of binary pulsar orbits and orbital period decay comparable to the General Relativistic gravitational wave model.

SZ-5 Cabin’s Height Changes during Three Super-storms in 2003

In this work,the daily height variations of SZ-5(Shenzhou-5) cabin from 22 October to 28 November in 2003 are analyzed,which includes the period of the Halloween Storm and the Great November Storm.The significant orbital decays have been observed at the end of October and in late November due to the great solar flares and the severe geomagnetic storms.According to the equation of the air-drag-force on a spacecraft and the SZ-5 orbital decay information,the relative daily average thermospheric density changes during the three 2003 super-storms are derived and the results are compared with the Naval Research Laboratory Mass Spectrometer Incoherent Scatter Radar Extended Model(NRLMSISE-00).The results show that the daily average thermospheric density(at the altitude of SZ-5,about 350 km) in storm time enhances to approximately 200% as much as that in the quiet time but the empirical model may somewhat underestimate the average thermospheric density changes and the daily contributions of geomagnetic storms to the density enhancements during these severe space weather events.

Atmospheric density determination using high-accuracy satellite GPS data

Atmospheric drag is the main source of error in the determination and prediction of the orbit of low Earth orbit （LEO） satellites; however, empirical models that are used to account for this often have density errors of around 15%-30%. Atmospheric density determination has thus become an important topic for researchers. Based on the relationship between file atmospheric drag force and the decay of the semi-major axis of the orbit, we derived atmospheric density along the trajectory of challenging mini-satellite payload （CHAMP） satellite with its rapid science orbit （RSO） data. Three primary parameters--the ratio of cross-sectional area to mass, the drag coefficient, and the decay of the semi-major axis caused by atmospheric drag--were calculated. We also analyse the source of the error and made a comparison between the GPS-derived and reference density. The result for December 2, 2008, showed that the mean error of the GPS-derived density could be decreased from 29.21% to 9.20%, if the time span adopted for the process of computation was increased from 10 min to 50 min. The result for the entire month of December indicated that a density precision of 10% could be achieved, when the time span meets the condition that the amplitude of the decay of the semi-major axis is much greater than its standard deviation.