scholarly journals A GA-SA Hybrid Planning Algorithm Combined with Improved Clustering for LEO Observation Satellite Missions

Algorithms ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 231
Author(s):  
Xiangyu Long ◽  
Shufan Wu ◽  
Xiaofeng Wu ◽  
Yixin Huang ◽  
Zhongcheng Mu
Keyword(s):  
Clustering Algorithm ◽  
Simulated Annealing Algorithm ◽  
Space Mission ◽  
Theory Model ◽  
Low Earth Orbit ◽  
Mission Planning ◽  
Experimental Simulation ◽  
Two Phase ◽  
Fitness Value ◽  
Planning Algorithm

This paper presents a space mission planning tool, which was developed for LEO (Low Earth Orbit) observation satellites. The tool is focused on a two-phase planning strategy with clustering preprocessing and mission planning, where an improved clustering algorithm is applied, and a hybrid algorithm that combines the genetic algorithm with the simulated annealing algorithm (GA–SA) is given and discussed. Experimental simulation studies demonstrate that the GA–SA algorithm with the improved clique partition algorithm based on the graph theory model exhibits higher fitness value and better optimization performance and reliability than the GA or SA algorithms alone.

scholarly journals An advance in transfer line chilldown heat transfer of cryogenic propellants in microgravity using microfilm coating for enabling deep space exploration

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
J. N. Chung ◽  
Jun Dong ◽  
Hao Wang ◽  
S. R. Darr ◽  
J. W. Hartwig
Keyword(s):  
Space Exploration ◽  
Fluid Management ◽  
Microgravity Condition ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Deep Space ◽  
Deep Space Exploration ◽  
Quenching Efficiency ◽  
Proper Perspective

AbstractThe extension of human space exploration from a low earth orbit to a high earth orbit, then to Moon, Mars, and possibly asteroids is NASA’s biggest challenge for the new millennium. Integral to this mission is the effective, sufficient, and reliable supply of cryogenic propellant fluids. Therefore, highly energy-efficient thermal-fluid management breakthrough concepts to conserve and minimize the cryogen consumption have become the focus of research and development, especially for the deep space mission to mars. Here we introduce such a concept and demonstrate its feasibility in parabolic flights under a simulated space microgravity condition. We show that by coating the inner surface of a cryogenic propellant transfer pipe with low-thermal conductivity microfilms, the quenching efficiency can be increased up to 176% over that of the traditional bare-surface pipe for the thermal management process of chilling down the transfer pipe. To put this into proper perspective, the much higher efficiency translates into a 65% savings in propellant consumption.

Robust Environmental Sensing Using UAVs

2021 ◽  
Vol 2 (4) ◽  
pp. 1-20
Author(s):  
Ahmed Boubrima ◽  
Edward W. Knightly
Keyword(s):  
Air Pollution ◽  
Gas Sensors ◽  
High Performance ◽  
Weather Conditions ◽  
Ambient Air ◽  
Mission Planning ◽  
Pollution Monitoring ◽  
Compound Pollution ◽  
Planning Algorithm

In this article, we first investigate the quality of aerial air pollution measurements and characterize the main error sources of drone-mounted gas sensors. To that end, we build ASTRO+, an aerial-ground pollution monitoring platform, and use it to collect a comprehensive dataset of both aerial and reference air pollution measurements. We show that the dynamic airflow caused by drones affects temperature and humidity levels of the ambient air, which then affect the measurement quality of gas sensors. Then, in the second part of this article, we leverage the effects of weather conditions on pollution measurements’ quality in order to design an unmanned aerial vehicle mission planning algorithm that adapts the trajectory of the drones while taking into account the quality of aerial measurements. We evaluate our mission planning approach based on a Volatile Organic Compound pollution dataset and show a high-performance improvement that is maintained even when pollution dynamics are high.

scholarly journals Clustering-Based Component Fraction Estimation in Solid–Liquid Two-Phase Flow in Dredging Engineering

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5697
Author(s):  
Chang Sun ◽  
Shihong Yue ◽  
Qi Li ◽  
Huaxiang Wang
Keyword(s):  
Clustering Algorithm ◽  
Two Phase Flow ◽  
Low Cost ◽  
Fast Response ◽  
New Method ◽  
Phase Flow ◽  
Reference Distribution ◽  
Two Phase ◽  
Long Time ◽  
Solid Liquid

Component fraction (CF) is one of the most important parameters in multiple-phase flow. Due to the complexity of the solid–liquid two-phase flow, the CF estimation remains unsolved both in scientific research and industrial application for a long time. Electrical resistance tomography (ERT) is an advanced type of conductivity detection technique due to its low-cost, fast-response, non-invasive, and non-radiation characteristics. However, when the existing ERT method is used to measure the CF value in solid–liquid two-phase flow in dredging engineering, there are at least three problems: (1) the dependence of reference distribution whose CF value is zero; (2) the size of the detected objects may be too small to be found by ERT; and (3) there is no efficient way to estimate the effect of artifacts in ERT. In this paper, we proposed a method based on the clustering technique, where a fast-fuzzy clustering algorithm is used to partition the ERT image to three clusters that respond to liquid, solid phases, and their mixtures and artifacts, respectively. The clustering algorithm does not need any reference distribution in the CF estimation. In the case of small solid objects or artifacts, the CF value remains effectively computed by prior information. To validate the new method, a group of typical CF estimations in dredging engineering were implemented. Results show that the new method can effectively overcome the limitations of the existing method, and can provide a practical and more accurate way for CF estimation.

Fluorinated Single Wall Nanotube/Polyethylene Composites for Multifunctional Radiation Protection

2002 ◽  
Vol 740 ◽  
Author(s):  
Merlyn X. Pulikkathara ◽  
Meisha L. Shofner ◽  
Richard T. Wilkins ◽  
Jesus G. Vera ◽  
Enrique V. Barrera ◽  
...  
Keyword(s):  
Radiation Protection ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Proton Radiation ◽  
Freeform Fabrication ◽  
Nanotube Composites ◽  
Total Fluence ◽  
Hydrogen Exposure ◽  
The Stability ◽  
Single Wall Nanotubes

ABSTRACTFluorinated Single Wall Nanotubes (f-SWNTs) have been processed in polyethylene by an incipient wetting technique to achieve a well dispersed nanocomposite for radiation protection. In some cases, samples were further processed using the rapid prototyping method of extrusion freeform fabrication. Composites were exposed to 40 MeV proton radiation with a flux of about 1.7×107 protons/cm2/sec to a total fluence of 3×1010 protons/cm2.This exposure is consistent with a long-term space mission in low earth orbit. The samples were evaluated by means of Raman spectroscopy and thermogravimetric analysis (TGA). These results were compared to the unexposed composite and unfilled polymer samples. This study has focused on the stability of the nanotube composites when exposed to radiation and prior to hydrogen exposure. It was shown that the stability of the functional group is not constant with SWNTs produced by different processes and that radiation exposure is capable of defluorinating SWNTs in polyethylene.

The research of parking mission planning algorithm for unmanned ground vehicle

ICCAS 2010 ◽  
2010 ◽  
Author(s):  
Jae-Hwan Kim ◽  
Chung-Kyeom Kim ◽  
Gyeong-Hwan Jo ◽  
Byong-Woo Kim
Keyword(s):  
Mission Planning ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicle ◽  
Planning Algorithm

One Variant of Manned Mission to Mars with a Nuclear Electric Propulsion

2011 ◽  
Vol 1 (2) ◽  
pp. 1-17 ◽  
Author(s):  
M. S. Konstantinov ◽  
H. W. Loeb ◽  
V. G. Petukhov ◽  
G. A. Popov
Keyword(s):  
Electric Propulsion ◽  
Space Mission ◽  
Optimization Criterion ◽  
Low Earth Orbit ◽  
Problem Definition ◽  
Specific Mass ◽  
Propulsion Systems ◽  
Propulsion Efficiency ◽  
Mass Minimization ◽  
Low Mass

In this paper, one possible way for implementing a manned mission to Mars is examined. Typical peculiarities of the mission are as follows: the nuclear electric propulsion; relatively low mass of the spacecraft at a low Earth orbit (200 tons) and the crew time in flight is high (900-1000 days). Space mission analysis of the chosen variant is performed. As an optimization criterion, the authors chose the fuel mass required for the flight. Under examined problem definition such mass minimization is equivalent to maximal final mass of the spacecraft and maximal permissible total mass of power and electric propulsion systems. The authors show that to implement the examined manned mission, it is necessary to create the nuclear electric power and electric propulsion systems with a specific mass lower than 12.5 kg/kW under propulsion efficiency of 0.8, specific mass of the system for propellant storage of 0.05 and manned spacecraft complex mass of 52.1 tons. Under propulsion efficiency of 0.7, specific mass of power-propulsion should be lower than 10.9 kg/kW.

scholarly journals Improving Motion Safety and Efficiency of Intelligent Autonomous Swarm of Drones

Drones ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 48
Author(s):  
Amin Majd ◽  
Mohammad Loni ◽  
Golnaz Sahebi ◽  
Masoud Daneshtalab
Keyword(s):  
State Of The Art ◽  
Holistic Approach ◽  
Integrated Approach ◽  
Mission Planning ◽  
Operating Environment ◽  
Intelligent Monitoring ◽  
Planning Algorithm ◽  
Definition Of ◽  
Formal Requirements ◽  
Swarm Mission

Interest is growing in the use of autonomous swarms of drones in various mission-physical applications such as surveillance, intelligent monitoring, and rescue operations. Swarm systems should fulfill safety and efficiency constraints in order to guarantee dependable operations. To maximize motion safety, we should design the swarm system in such a way that drones do not collide with each other and/or other objects in the operating environment. On other hand, to ensure that the drones have sufficient resources to complete the required task reliably, we should also achieve efficiency while implementing the mission, by minimizing the travelling distance of the drones. In this paper, we propose a novel integrated approach that maximizes motion safety and efficiency while planning and controlling the operation of the swarm of drones. To achieve this goal, we propose a novel parallel evolutionary-based swarm mission planning algorithm. The evolutionary computing allows us to plan and optimize the routes of the drones at the run-time to maximize safety while minimizing travelling distance as the efficiency objective. In order to fulfill the defined constraints efficiently, our solution promotes a holistic approach that considers the whole design process from the definition of formal requirements through the software development. The results of benchmarking demonstrate that our approach improves the route efficiency by up to 10% route efficiency without any crashes in controlling swarms compared to state-of-the-art solutions.

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