The authors examine two different non-geostationary satellite constellation networks with intersatellite links for global air traffic control and air passenger communication. After developing a traffic model for aeronautical communication services, the authors derive bandwidth requirements for such a global system. The influence of different routing policies is discussed and they show that link...

1 0-7803-7651-X/03/$17.00 © 2003 IEEE 2 IEEEAC paper #1197, Updated December 10, 2002 Abstract—Proposed satellite constellation networks, based on Geostationary Earth Orbit (GEO) satellites, Medium Earth Orbit (MEO), and Low Earth Orbit (LEO) systems, will be required to transport IP traffic and to provide quality of service (QoS). This paper proposes a new Diffserv-based scheme of IP bandwidth...

0163-6804/97/$10.00 © 1997 IEEE here are two well-established methods for providing wireless communication services: terrestrially based systems, as used in cellular and personal communications systems (PCS), and satellites. Each concept has its specific advantages and disadvantages. The high-altitude aeronautical platform (HAAP) technology, we will argue, would have many of the advantages of b...

In this paper we present and evaluate a hybrid-modular multiple access protocol for ATM transmission in a multiservice satellite system. Given appropriate synchronization and Doppler (shift) compensation, the protocol components can cope with the dynamics of the satellite constellation and are suitable to both mobile and fixed user environments. The general protocol framework is first given wit...

1 0-7803-7651-X/03/$17.00 © 2003 IEEE 2 IEEEAC paper #1197, Updated December 10, 2002 Abstract—Proposed satellite constellation networks, based on Geostationary Earth Orbit (GEO) satellites, Medium Earth Orbit (MEO), and Low Earth Orbit (LEO) systems, will be required to transport IP traffic and to provide quality of service (QoS). This paper proposes a new Diffserv-based scheme of IP bandwidth...

Mars Sample Return is the highest priority science mission for the next decade as recommended by the 2011 Decadal Survey of Planetary Science [1]. This article presents the results of a feasibility study for a Mars Sample Return mission that efficiently uses emerging commercial capabilities expected to be available in the near future. The motivation of our study was the recognition that emergin...

Answer Just before the moon passes into the shadow of the earth it is almost collinear with the sun and earth and on the opposite side of the earth from the sun [1]. This means that when viewed from the earth it is fully illuminated (full moon) [1]. The orbit of the moon around the earth is not coplanar with the orbit of the Ear th around the sun [1]. A full lunar eclipse can only occur if full...

The Sun’s gradual brightening will seriously compromise the Earth’s biosphere within ∼ 109 years. If Earth’s orbit migrates outward, however, the biosphere could remain intact over the entire main-sequence lifetime of the Sun. In this paper, we explore the feasibility of engineering such a migration over a long time period. The basic mechanism uses gravitational assists to (in effect) transfer ...

In around 5 gigayears our Sun will grow to a Red Giant and will swallow Earth. In this article we present a rescue-plan for the whole mankind, including its inherited habitat Earth. The plan is subdivided into two parts: If we content ourselves to survive only the next 5 Gy (until the shellburning phase of our Sun) we propose to construct some kind of parasol to shadow Earth rather than to move...