The precise orbit determination (POD) for BeiDou satellites is usually limited by the insufficient quantity and poor distribution of ground tracking stations. To cope with this problem, this study used the GPS and BeiDou joint POD method based on Chinese national continuous operating reference stations (CNCORS) and IGS/MGEX stations. The results show that the 3D RMS of the differences of overla...

We analyse the projected radial distribution of satellites around bright primary galaxies in the 2dFGRS. We have considered several primary-satellite subsamples to search for dependences of the satellite number density profiles, ρ(rp), on properties of satellites and primaries. We find significant differences of the behaviour of ρ(rp) depending on primary characteristics. In star-forming primar...

Future planetary exploration of the outer satellites of the Solar System will require higher levels of onboard automation, including autonomous determination of sites where the probability of significant scientific findings is highest. Generally, the level of needed automation is heavily influenced by the distance between Earth and the robotic explorer(s) (e.g. spacecraft(s), rover(s), and ball...

Passive stabilization methods for satellites have undergone extensive research and development. Recently the number of small satellites (satellites less than I 00 kg.) has increased dramatically. This has lead to increased use of passive stabilization methods, such as gravity-gradient The core of a gravity-gradient stabilization system is a deployable boom with a damping mechanism. Traditionall...

We present a systematic survey for satellites of Venus using the BaadeMagellan 6.5 meter telescope and IMACS wide-field CCD imager at Las Campanas observatory in Chile. In the outer portions of the Hill sphere the search was sensitive to a limiting red magnitude of about 20.4, which corresponds to satellites with radii of a few hundred meters when assuming an albedo of 0.1. In the very inner po...