With the upcoming launch of large constellations satellites in low-Earth orbit (LEO) region, it will become important to organize physical space occupied by different operating order minimize critical conjunctions and avoid collisions. This paper introduces definition occupancy as domain an individual satellite moves along its nominal under effects environmental perturbations throughout a given...

In recent years the use of small multi mission satellites (SMMS) in Low Earth Orbit (LEO) for making voice, data and E-mail communications has been grown extensively. Low production cost, Low cost of lunching and low transmission power due to it’s low orbit of these satellites are some reasons for their vast usage. How over because of their low orbit they need to turn several times around the e...

The orbit determination of a satellite in a geostationary orbit is usually based on optical observations. Telescopes all around the Earth are observing the geostationary ring to obtain periodically new measurements in order to update the estimation of the objects’ orbits. One critical aspect of the orbit determination process is the initial orbit determination because no a priori information ar...

It is shown that the ratio of the e + over e − flux below the geomagnetic cutoff reported recently by the AMS experiment is due to the geomagnetic East-West effect. New measurements of particle fluxes close to earth have been performed recently by the AMS experiment, providing a body of highly accurate new data on particle populations in the close terrestrial environment, which open new prospec...

NASA Lewis Research Center (LeRC) is developing the space and ground segnumt technologies necessary to demonsUa_ a direct data distribution (D 3) system for use in space-to-ground communication links fzom spa_r_ in low-Earthorbit (LEO) to strategically located tracking ground terminals. The key space segment technologies include a K-band (19 GHz) MMICbased transmit phased array antem_ and a mul...

satellite thermal control ensures safe operating temperature ranges for satellite components throughout the mission life. effects of altitude, spin, and position of satellite radiator(s) on the thermal control of a small low earth orbit (leo) satellite have been studied. results show that change in satellite altitude, in the range considered here, does not produce critical thermal conditions. h...

Infrared Earth horizon sensors (EHS) are capable of providing attitude knowledge for satellites in low-Earth orbit, even during periods of eclipse. Attitude information is acquired by detecting Earth’s infrared electromagnetic radiation and, subsequently, determining the region obscured by Earth in the sensors’ fields of view to compute a nadir vector estimation in the satellite’s body frame. D...

This paper presents results from a contingency trajectory analysis performed for the Lunar Atmosphere & Dust Environment Explorer (LADEE) mission in the event of a missed lunar-orbit insertion (LOI) maneuver by the LADEE spacecraft. The effects of varying solar perturbations in the vicinity of the weak stability boundary (WSB) in the Sun-Earth system on the trajectory design are analyzed and di...

On-orbit servicing (OOS) presents new opportunities for refueling, inspection, repair, maintenance, and upgrade of spacecraft (s/c). OOS missions s/c in a geostationary orbit (GEO) are currently underway. However, there no plans low-Earth-orbit (LEO) s/c, aside from technology demonstrations, because their shorter design life lower cost. Designing systems LEO constellations differs that GEO-bas...