This paper addresses the networking issues of an ongoing project that evaluates the feasibility of a system consisting of a large constellation of low-earth-orbit (LEO) Laser Communication Satellites (LCS). Due to the strict payload constraints imposed by the LCS technology, we propose a lightweight, link-layer, source-based routing protocol that will extend the LEO infrastructure to the fast g...

Integral linear energy transfer (LET) spectra of cosmic radiation (CR) particles were measured on five Cosmos series spacecraft in low Earth orbit (LEO). Particular emphasis is placed on results of the Cosmos 1887 biosatellite which carried a set of joint U.S.S.R.-U.S.A. radiation experiments involving passive detectors that included thermoluminescent detectors (TLDs), plastic nuclear track de...

This article deals with the problem of optimal static output feedback control of linear periodic systems in continuous time, for which a continuous-time approach, which allows to deal with both stable and unstable open loop systems, is presented. The proposed approach is tested on the problem of designing attitude control laws for a Low-Earth Orbit (LEO) satellite on the basis of feedback from ...

An analytical framework for the efficient evaluation of the performance of complete sharing (CS) and complete partitioning (CP) resource sharing policies under a newly proposed general channel management strategy for multi-class traffic in Low Earth Orbit-Mobile Satellite Systems (LEO-MSS) is presented. This strategy gives a higher priority to handover calls over new calls by combine the guard ...

AbstmctThe geographical connection admission control (GCAC) algorithm is introduced for low earth orbit LEO) satellite networks. The GCAC scheme estimates the L u r e handover blocking probability of a new call attempt based on the user location database, in order to decrease the handover blocking. By simulation, it is shown that the proposed GCAC scheme guarantees the handover blocking probabi...

This paper presents a coded modulation scheme based on M-ary orthogonal modulation by means of Walsh–Hadamard (WH) sequences, suitable for low-earth-orbit (LEO) direct sequence/code division multiple access (DS/CDMA) satellite communication systems. Based on the IS-95 scheme, we consider Reed–Solomon (RS)-coded M-ary orthogonal modulation with error or erasures decoding, which presents good per...

The “traditional” way of designing constellations of communications satellites in low Earth orbit is to optimize the design for a specified global capacity. This approach is based on a forecast of the expected number of users and their activity level, both of which are highly uncertain. This can lead to economic failure if the actual demand is significantly smaller than the one predicted. This ...

Offering space-based Internet services with mega-constellations of low Earth orbit (LEO) satellites is a promising solution to connecting the unconnected. It can complement coverage terrestrial networks help bridge digital divide. However, there are challenges from operational obstacles technical hurdles facing development LEO satellite access. This article provides an overview state art in acc...

Precise orbit determination (POD) of low earth orbiters (LEOs) with GPS is becoming a standard practice in the space science community. The need for such information has been growing rapidly due to such scientific applications as radio occultation and ever increasing demands from engineering applications such as spacebased earth sensor positioning. The conventional GPSbased POD strategies rely ...