scholarly journals Efficiency in Carrying Cargo to Earth Orbits: Spaceports Repositioning

2016 ◽  
Vol 4 (20) ◽  
pp. 6
Author(s):  
Jakub Hospodka ◽  
Zdeněk Houfek
Keyword(s):  
Earth Rotation ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Atmospheric Drag ◽  
Significant Cost ◽  
Space Flights ◽  
Kennedy Space Center ◽  
Kennedy Space ◽  
Earth Orbits ◽  
Launch Platform

Space flights are in these days not any more question of technology, but more question of costs. One way how to decrease cost of launch is change of home spaceport. Change of home spaceport for different rockets is a way to achieve more efficient launches to space. The reason is different acceleration achieved from Earth rotation. We added several mathematical calculations of missions to Low Earth Orbit and Geostationary Earth Orbit to show bonuses from Earth rotation and effect of atmospheric drag on specific rockets used these days. We discussed only already used space vessels. Namely Arianne 5, Delta 4 heavy, Proton-M, Zenit and Falcon9. For reaching GEO we discuss possibility of using Hohmman transfer, because none of aforementioned vessels is available for direct GEO entry. As possible place for launch we discussed spaceports Baikonur, Kennedy Space center, Guyana Space center and Sea Launch platform. We present results in form of additional acceleration for each spaceport, and we also project this additional acceleration in means payload increase. In conclusion we find important differences between vessel effectivity based on spaceport used for launch. Change of launch location may bring significant cost decrease for operators.

Atomic Oxygen Plasma Effects on Cvd Deposited Diamond-Like Carbon Films

1991 ◽  
Vol 236 ◽  
Author(s):  
Jeffrey S. Hale ◽  
R.A. Synowicki ◽  
S. Nafis ◽  
John A. Woollam
Keyword(s):  
Atomic Oxygen ◽  
Moisture Absorption ◽  
Crystalline Silicon ◽  
Carbon Films ◽  
Fused Silica ◽  
Low Earth Orbit ◽  
Index Of Refraction ◽  
Earth Orbit ◽  
Diamond Like Carbon ◽  
Space Flights

AbstractCVD deposited diamond-like carbon (DLC) films have been studied for possible use as a secondary standard for Low Earth Orbit materials degradation. Samples of various thicknesses have been exposed to a simulated Low Earth Orbit atomic oxygen (AO) environment using a plasma asher. Mass loss measurements indicate that DLC degrades at a rate of 0.7 mg/hr which is two to three times the rate of currently used Kapton samples which degrade at a rate of.3 mg/hr. Thickness measurements show that DLC thins at a rate of 77 Angstroms/min. Since DLC is not as susceptible to environmental factors such as moisture absorption, it could potentially provide more accurate measurements of AO fluence on short space flights. Adhesion of DLC films to both fused silica and crystalline silicon substrates has been studied under thermal cycling conditions. Film adhesion to fused silica can be enhanced by sputtering a thin layer of silicon dioxide onto the substrate prior to deposition. In addition to the above, the index of refraction and extinction coefficient of various thicknesses of DLC films has been characterized by Variable Angle Spectroscopic Ellipsometry.

Atomic Oxygen Plasma Effects on CVD Deposited Diamond-Like Carbon Films

1991 ◽  
Vol 235 ◽  
Author(s):  
Jeffrey S. Hale ◽  
R. A. Synowicki ◽  
S. Nails ◽  
John A. Woollam
Keyword(s):  
Atomic Oxygen ◽  
Moisture Absorption ◽  
Crystalline Silicon ◽  
Carbon Films ◽  
Fused Silica ◽  
Low Earth Orbit ◽  
Index Of Refraction ◽  
Earth Orbit ◽  
Diamond Like Carbon ◽  
Space Flights

ABSTRACTCVD deposited diamond-like carbon (DLC) films have been studied for possible use as a secondary standard for Low Earth Orbit materials degradation. Samples of various thicknesses have been exposed to a simulated Low Earth Orbit atomic oxygen (AO) environment using a plasma asher. Mass loss measurements indicate that DLC degrades at a rate of 0.7 mg/hr which is two to three times the rate of currently used Kapton samples which degrade at a rate of.3 mg/hr. Thickness measurements show that DLC thins at a rate of 77 Angstroms/min. Since DLC is not as susceptible to environmental factors such as moisture absorption, it could potentially provide more accurate measurements of AO fluence on short space flights. Adhesion of DLC films to both fused silica and crystalline silicon substrates has been studied under thermal cycling conditions. Film adhesion to fused silica can be enhanced by sputtering a thin layer of silicon dioxide onto the substrate prior to deposition. In addition to the above, the index of refraction and extinction coefficient of various thicknesses of DLC films has been characterized by Variable Angle Spectroscopic Ellipsometry.

scholarly journals Increasing the Accuracy of Orbital Elements for a Satellite in a Low Earth Orbit under the Influence of Atmospheric Drag Using Adams-Bashforth Method

2021 ◽  
pp. 81-90
Author(s):  
Rasha H. Ibrahim ◽  
Abdul-Rahman H. Saleh
Keyword(s):  
Integration Method ◽  
Major Axis ◽  
Low Earth Orbit ◽  
True Anomaly ◽  
Earth Orbit ◽  
Atmospheric Drag ◽  
Orbital Elements ◽  
Semi Major Axis ◽  
Literature Reviews ◽  
Perturbed Equation

The perturbed equation of motion can be solved by using many numerical methods. Most of these solutions were inaccurate; the fourth order Adams-Bashforth method is a good numerical integration method, which was used in this research to study the variation of orbital elements under atmospheric drag influence.  A satellite in a Low Earth Orbit (LEO), with altitude form perigee = 200 km, was selected during 1300 revolutions (84.23 days) and ASat / MSat value of 5.1 m2/ 900 kg. The equations of converting state vectors into orbital elements were applied. Also, various orbital elements were evaluated and analyzed. The results showed that, for the semi-major axis, eccentricity and inclination have a secular falling discrepancy, Longitude of Ascending Node is periodic, Argument of Perigee has a secular increasing variation, while true anomaly grows linearly from 0 to 360°. Furthermore, all orbital elements, excluding Longitude of Ascending Node, Argument of Perigee, and true anomaly, were more affected by drag than other orbital elements, through their falling as the time passes. The results illustrate a high correlation as compared with literature reviews in this field.

scholarly journals Atmospheric drag effects on modelled low Earth orbit (LEO) satellites during the July 2000 Bastille Day event in contrast to an interval of geomagnetically quiet conditions

2021 ◽  
Vol 39 (3) ◽  
pp. 397-412
Author(s):  
Victor U. J. Nwankwo ◽  
William Denig ◽  
Sandip K. Chakrabarti ◽  
Muyiwa P. Ajakaiye ◽  
Johnson Fatokun ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Satellite Orbits ◽  
Percentage Increase ◽  
Atmospheric Drag ◽  
Drag Effect ◽  
Satellite Drag ◽  
Ballistic Coefficient ◽  
The Impact

Abstract. In this work, we simulated the atmospheric drag effect on two model SmallSats (small satellites) in low Earth orbit (LEO) with different ballistic coefficients during 1-month intervals of solar–geomagnetic quiet and perturbed conditions. The goal of this effort was to quantify how solar–geomagnetic activity influences atmospheric drag and perturbs satellite orbits, with particular emphasis on the Bastille Day event. Atmospheric drag compromises satellite operations due to increased ephemeris errors, attitude positional uncertainties and premature satellite re-entry. During a 1-month interval of generally quiescent solar–geomagnetic activity (July 2006), the decay in altitude (h) was a modest 0.53 km (0.66 km) for the satellite with the smaller (larger) ballistic coefficient of 2.2×10-3 m2 kg−1 (3.03×10-3 m2 kg−1). The associated orbital decay rates (ODRs) during this quiet interval ranged from 13 to 23 m per day (from 16 to 29 m per day). For the disturbed interval of July 2000 the significantly increased altitude loss and range of ODRs were 2.77 km (3.09 km) and 65 to 120 m per day (78 to 142 m per day), respectively. Within the two periods, more detailed analyses over 12 d intervals of extremely quiet and disturbed conditions revealed respective orbital decays of 0.16 km (0.20 km) and 1.14 km (1.27 km) for the satellite with the smaller (larger) ballistic coefficient. In essence, the model results show that there was a 6- to 7-fold increase in the deleterious impacts of satellite drag between the quiet and disturbed periods. We also estimated the enhanced atmospheric drag effect on the satellites' parameters caused by the July 2000 Bastille Day event (in contrast to the interval of geomagnetically quiet conditions). The additional percentage increase, due to the Bastille Day event, to the monthly mean values of h and ODR are 34.69 % and 50.13 % for Sat-A and 36.45 % and 68.95 % for Sat-B. These simulations confirmed (i) the dependence of atmospheric drag force on a satellite's ballistic coefficient, and (ii) that increased solar–geomagnetic activity substantially raises the degrading effect of satellite drag. In addition, the results indicate that the impact of short-duration geomagnetic transients (such as the Bastille Day storm) can have a further deleterious effect on normal satellite operations. Thus, this work increases the visibility and contributes to the scientific knowledge surrounding the Bastille Day event and also motivates the introduction of new indices used to describe and estimate the atmospheric drag effect when comparing regimes of varying solar–geomagnetic activity. We suggest that a model of satellite drag, when combined with a high-fidelity atmospheric specification as was done here, can lead to improved satellite ephemeris estimates.

scholarly journals Charting Satellite Courses in a Crowded Thermosphere

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Sean Bruinsma ◽  
Mariangel Fedrizzi ◽  
Jia Yue ◽  
Christian Siemes ◽  
Stijn Lemmens
Keyword(s):  
Low Earth Orbit ◽  
Earth Orbit ◽  
Atmospheric Drag

As the number of satellites in low Earth orbit grows by leaps and bounds, accurate calculations of the effects of atmospheric drag on their trajectories are becoming critically important.

Orbital transfer vehicle (OTV) system sizing study for manned GEO satellite servicing

2016 ◽  
Vol 120 (1226) ◽  
pp. 573-599 ◽  
Author(s):  
B. Chudoba ◽  
G. Coleman ◽  
L. Gonzalez ◽  
E. Haney ◽  
A. Oza ◽  
...  
Keyword(s):  
Low Earth Orbit ◽  
Geostationary Orbit ◽  
Earth Orbit ◽  
Orbital Transfer ◽  
Geo Satellite ◽  
Satellite Servicing ◽  
Geo Satellites ◽  
Kennedy Space ◽  
Cost Factors ◽  
Concept Of Operations

ABSTRACTIn an effort to quantify the feasibility of candidate space architectures for astronauts servicing Geosynchronous Earth Orbit (GEO) satellites, a conceptual assessment of architecture-concept and operations-technology combinations has been performed. The focus has been the development of a system with the capability to transfer payload to and from geostationary orbit. Two primary concepts of operations have been selected: (a) Direct insertion/re-entry (Concept of Operations 1 – CONOP 1); (b) Launch to low-earth orbit at Kennedy Space Center inclination angle with an orbital transfer to/from geostationary orbit (Concept of Operations 2 – CONOP 2). The study concludes that a capsule and de-orbit propulsion module system sized for the geostationary satellite servicing mission is feasible for a direct insertion/re-entry concept of operation CONOP 1. Vehicles sized for CONOP 2 show overall total mass savings when utilising the aero-assisted orbital transfer vehicle de-orbit propulsion module options compared to the pure propulsive baseline cases. Overall, the consideration of technical, operational and cost factors determine if either the aero-assisted orbital transfer vehicle concepts or the re-usable/expendable ascent/de-orbit propulsion modules is the preferred option.

scholarly journals Estimating the lifetime and Reentry of the Aluminum Space Debris of Sizes (1 and 10 cm) in LEO under Atmosphere Drag Effects

2020 ◽  
Vol 12 (02) ◽  
pp. 66-75
Author(s):  
H. K. Al-Zaidi ◽  
◽  
M. J. Al-Bermani ◽  
A.M. Taleb ◽  
Keyword(s):  
Drag Force ◽  
Space Debris ◽  
Atmospheric Model ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Atmospheric Drag ◽  
Kutta Method ◽  
Runge Kutta Method ◽  
Geomagnetic Activities ◽  
Dense Atmosphere

This study attempts to address the lifetime and reentry of the space debris in low earth orbit LEO which extends from 200 to 1200 km. In this study a new Computer programs were designed to simulate the orbit dynamics of space debris lifetime and reentry under atmospheric drag force using Runge-Kutta Method to solve the differential equations of drag force. This model was adapted with the Drag Thermosphere Model (DTM78, 94), the Aluminum 2024 space debris in certain size (1&10 cm) were used in this study, which is frequently employed in the structure of spacecraft and aerospace designs. The selected atmospheric model for this investigation was the drag thermospheric models DTM78 and DTM94, because of this dependence on solar and geomagnetic activities. It was found that the lifetime of the space debris increases with increasing perigee altitudes. It was also found that the elliptical shape of the debris orbit would change gradually into a circular shape, then its kinetic energy would be transformed into heat and hence the debris might be destroyed in the dense atmosphere.

The Holographic Solar Photon Thruster (SPT) : A Low-Earth Orbit Solar Sail

Solar Energy ◽  
2003 ◽  
Author(s):  
Gregory L. Matloff
Keyword(s):  
Solar Sail ◽  
Low Earth Orbit ◽  
Back Pressure ◽  
Orbital Energy ◽  
Earth Orbit ◽  
Atmospheric Drag ◽  
Net Radiation ◽  
Solar Sails ◽  
The Earth ◽  
Fixed Orientation

Atmospheric drag limits most solar sails to altitudes>1000 km. A two-sail variant, the Solar-Photon Thruster (SPT) , could be used in Low-Earth Orbit (LEO). An SPT has a fixed-orientation collector sail that focuses light against a smaller, adjustable thruster sail. Maintaining the collector surface parallel to the Earth minimizes SPT drag in LEO. To minimize solar-radiation back pressure towards Earth, the upper collector surface is non-reflective. The reflective lower collector surface directs light reflected and reradiated from the Earth against the thruster. Thruster orientation is adjusted in LEO to increase the orbital energy by the net radiation-pressure. Experiments reveal that holograms are tolerant to solar-wind radiation. SPTs with white-light holographic thrusters are useful in LEO because small thruster rotations produce greatly altered reflectivity. It may be possible to holographically combine SPT collector and thruster.

scholarly journals Atmospheric Drag Alters Satellite Orbits

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
David Shultz
Keyword(s):  
Low Earth Orbit ◽  
Earth Orbit ◽  
Satellite Orbits ◽  
Atmospheric Drag ◽  
Modeling Study

A new modeling study shows how the density of the thermosphere influences the paths of satellites in low Earth orbit.

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