This paper will present the methods adapted to model low earth orbiting (LEO) spacecraft support and an actual implementation of this approach. The results of a comparison of actual human schedulers' performance and the support schedules developed by using the proposed modeling approach will be presented. Indications based on two years of performance tracking of the new approach are that modeli...

Almost two-thirds of the humankind currently does not have access to the Internet, wired or wireless. We present a Space Internet proposal capable of providing Zetabyte/ month capacity which is equivalent to 200GB/month for 5 Billion users Worldwide. Our proposal is based on deploying thousands of low-cost micro-satellites in Low-Earth Orbit (LEO), each capable of providing Terabit/s data rates...

A new routing algorithm for Low-earth orbit (LEO) satellite networks is designed in this study. For this reason genetic algorithms are used. A new objective function is obtained to find the suitable path according to the criteria of the delay and an aging factor. Also Call Blocking Probabilities (CBPs) are considered due to the dynamic nature of the satellite systems. This dynamic routing type ...

In this paper we propose a serial-parallel correlator (SPC) for the purpose of PN code acquisition in a low earth orbit (LEO) satellite environment. To reduce the effect of severe Doppler in a LEO satellite channel, we combine the SPC with an FFT technique to combat the carrier frequency offset due to Doppler shift. By using the FFT technique we omit the need for an additional search over the f...

GPS receivers nowadays provide a well established system for tracking of spacecraft in low-Earth orbit (LEO). In addition, GPS receivers serve as instruments for geodetic and atmospheric research on an ever growing number of science missions. The paper provides an overview of existing GPS receivers for LEO satellites, covering both fully space qualified as well as commercial-off-the-shelf (COTS...

The Universal Mobile Telecommunications System (UMTS) will provide multimedia services to users in whatever environment via uniform service access procedures. Efficient Medium Access Control (MAC) protocols are needed to guarantee high capacity. This paper deals with Packet Reservation Multiple Access (PRMA), an efficient MAC protocol that has been widely studied in terrestrial microcellular sy...

A space transportation infrastructure is described that utilizes propellant depots to support all foreseeable missions in the Earth-Moon vicinity and deep space out to Mars. The infrastructure utilizes current expendable launch vehicles such as the Delta IV Heavy, Atlas V, and Falcon 9, for all crew, cargo, and propellant launches to orbit. Propellant launches are made to a Low-Earth-Orbit (LEO...

In contrast with ground applications the GNSS constellations are not optimized for space applications. Moreover, the different types of mission, i.e. Low Earth Orbit (LEO), Medium Earth Orbit (MEO), Geosynchronous Earth Orbit (GEO), have all specific requirements. Our motivation is to define an «Ubiquitous GNSS receiver (UGNSS)», i.e. a single receiver able to cope with all types of mission. Th...