In space, radio frequencies (RFs) are usually used for long-distance linkage. However, recent progress in optics and laser technologies, especially in fiber optics, is ushering in an era of inter-orbit communications using laser beams. Both RFs and optical waves are electromagnetic waves, but optical waves offer many advantages in space, including reduced mass, power, and volume of equipment, h...

The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard positioning service with positioning accuracy of about 10 m, both precise relative positioning and precise...

In this work we describe a method to handle curved orbits in wavenumber domain focusing algorithm for high-resolution SAR data acquired by Low Earth Orbit satellites using spotlight mode. The standard wavenumber domain focusing algorithm make assumptions that start to be invalid when applied to high-resolution spotlight SAR data acquired in spaceborne low Earth orbit (LEO) configurations. The a...

In this paper the problem of sending a spacecraft from Low Earth Orbit (LEO) to the Moon with minimum fuel consumption is considered. It is assumed that the "Two-Body model" approximation is valid in all phases of the mission and that the final orbit around the Moon is polar. The first part deals with impulsive maneuvers, and obtain a set of values for fuel expenditure and trip time for several...

The space around the Earth is filled with man-made objects, which orbit the planet at altitudes ranging from hundreds to tens of thousands of kilometers. Keeping an eye on all objects in Earth's orbit, useful and not useful, operational or not, is known as Space Surveillance. Due to cost considerations, the space surveillance solutions beyond the Low Earth Orbit region are mainly based on optic...

ROUTING AND NETWORK MOBILITY MANAGEMENT IN NEXT GENERATION SATELLITE NETWORKS Satellite networks are an attractive option to provide broadband telecommunication services to globally scattered users, due to their extensive geographic coverage, high bandwidth availability, inherent broadcast capabilities, etc. Satellites rotating in geostationary orbit (GEO) are very well suited for broadcast ser...

The possibility of analyzing the node Ω of the GP-B satellite in order to measure also the Lense-Thirring effect on its orbit is examined. This feature is induced by the general relativistic gravitomagnetic component of the Earth gravitational field. The GP-B mission has been launched in April 2004 and is aimed mainly to the measurement of the gravitomagnetic precession of four gyroscopes carri...

It is well known that electrons, protons, and heavier ions can be accelerated to high energies (~1 MeV) throughout the solar system by a variety of mechanisms. We review several of the sources of energetic ions and electrons that can produce enhanced fluxes of particles near the Earth's orbit. Solar energetic particles and particles accelerated at interplanetary shock waves are considered. We a...

Effective satellite mission operations are directly impacted by the ability to generate accurate and precise orbit predictions. High precision orbit determination processes rely on detailed force models to propagate an orbit solution and predict future orbit behavior. While gravity forces are typically well understood, the modeling of non-conservative forces is often more challenging, causing i...

Plans to pursue space expeditionary missions beyond Earth orbit have occasioned renewed concern that crew behavioral health and performance effectiveness, along with spacecraft habitability, will present major challenges to the success of spaceflight initiatives involving unprecedented increases in time and distance on interplanetary voyages. A programmed environment methodological approach tha...