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Publisher: Elsevier   (Total: 3163 journals)

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Showing 1 - 200 of 3163 Journals sorted alphabetically
A Practical Logic of Cognitive Systems     Full-text available via subscription   (Followers: 9)
AASRI Procedia     Open Access   (Followers: 14)
Academic Pediatrics     Hybrid Journal   (Followers: 30, SJR: 1.655, CiteScore: 2)
Academic Radiology     Hybrid Journal   (Followers: 22, SJR: 1.015, CiteScore: 2)
Accident Analysis & Prevention     Partially Free   (Followers: 88, SJR: 1.462, CiteScore: 3)
Accounting Forum     Hybrid Journal   (Followers: 25, SJR: 0.932, CiteScore: 2)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 35, SJR: 1.771, CiteScore: 3)
Achievements in the Life Sciences     Open Access   (Followers: 5)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 7)
Acta Astronautica     Hybrid Journal   (Followers: 395, SJR: 0.758, CiteScore: 2)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 27, SJR: 1.967, CiteScore: 7)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 2)
Acta de Investigación Psicológica     Open Access   (Followers: 3)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.18, CiteScore: 1)
Acta Haematologica Polonica     Free   (Followers: 1, SJR: 0.128, CiteScore: 0)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.661, CiteScore: 2)
Acta Materialia     Hybrid Journal   (Followers: 243, SJR: 3.263, CiteScore: 6)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.504, CiteScore: 1)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.542, CiteScore: 1)
Acta Oecologica     Hybrid Journal   (Followers: 10, SJR: 0.834, CiteScore: 2)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 2, SJR: 0.307, CiteScore: 0)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 1, SJR: 1.793, CiteScore: 6)
Acta Poética     Open Access   (Followers: 4, SJR: 0.101, CiteScore: 0)
Acta Psychologica     Hybrid Journal   (Followers: 27, SJR: 1.331, CiteScore: 2)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.052, CiteScore: 2)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 3, SJR: 0.374, CiteScore: 1)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.344, CiteScore: 1)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 6, SJR: 0.19, CiteScore: 0)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 6)
Acute Pain     Full-text available via subscription   (Followers: 15, SJR: 2.671, CiteScore: 5)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.53, CiteScore: 4)
Addictive Behaviors     Hybrid Journal   (Followers: 16, SJR: 1.29, CiteScore: 3)
Addictive Behaviors Reports     Open Access   (Followers: 8, SJR: 0.755, CiteScore: 2)
Additive Manufacturing     Hybrid Journal   (Followers: 9, SJR: 2.611, CiteScore: 8)
Additives for Polymers     Full-text available via subscription   (Followers: 22)
Advanced Cement Based Materials     Full-text available via subscription   (Followers: 3, SJR: 0.732, CiteScore: 3)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 137, SJR: 4.09, CiteScore: 13)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.167, CiteScore: 4)
Advanced Powder Technology     Hybrid Journal   (Followers: 16, SJR: 0.694, CiteScore: 3)
Advances in Accounting     Hybrid Journal   (Followers: 8, SJR: 0.277, CiteScore: 1)
Advances in Agronomy     Full-text available via subscription   (Followers: 12, SJR: 2.384, CiteScore: 5)
Advances in Anesthesia     Full-text available via subscription   (Followers: 28, SJR: 0.126, CiteScore: 0)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 10, SJR: 0.992, CiteScore: 1)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 10, SJR: 1.551, CiteScore: 4)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 2.089, CiteScore: 5)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 14, SJR: 0.572, CiteScore: 2)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.61, CiteScore: 7)
Advances in Botanical Research     Full-text available via subscription   (Followers: 2, SJR: 0.686, CiteScore: 2)
Advances in Cancer Research     Full-text available via subscription   (Followers: 29, SJR: 3.043, CiteScore: 6)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 7, SJR: 1.453, CiteScore: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 1.992, CiteScore: 5)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 3)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 27, SJR: 0.156, CiteScore: 1)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.713, CiteScore: 1)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 10, SJR: 1.316, CiteScore: 2)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 28, SJR: 1.562, CiteScore: 3)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19, SJR: 1.977, CiteScore: 8)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.205, CiteScore: 1)
Advances in Dermatology     Full-text available via subscription   (Followers: 15)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 8)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 23)
Advances in Ecological Research     Full-text available via subscription   (Followers: 42, SJR: 2.524, CiteScore: 4)
Advances in Engineering Software     Hybrid Journal   (Followers: 27, SJR: 1.159, CiteScore: 4)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 43, SJR: 5.39, CiteScore: 8)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 1)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 53, SJR: 0.591, CiteScore: 2)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 1.354, CiteScore: 4)
Advances in Genome Biology     Full-text available via subscription   (Followers: 8, SJR: 12.74, CiteScore: 13)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 1.193, CiteScore: 3)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21, SJR: 0.368, CiteScore: 1)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11, SJR: 0.749, CiteScore: 3)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.193, CiteScore: 0)
Advances in Immunology     Full-text available via subscription   (Followers: 37, SJR: 4.433, CiteScore: 6)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 1.163, CiteScore: 2)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.938, CiteScore: 3)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6, SJR: 0.176, CiteScore: 0)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.682, CiteScore: 2)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 14, SJR: 0.88, CiteScore: 2)
Advances in Mathematics     Full-text available via subscription   (Followers: 11, SJR: 3.027, CiteScore: 2)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.694, CiteScore: 2)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.158, CiteScore: 3)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 21)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.182, CiteScore: 0)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 3)
Advances in Oncobiology     Full-text available via subscription   (Followers: 1)
Advances in Organ Biology     Full-text available via subscription   (Followers: 1)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 16, SJR: 1.875, CiteScore: 4)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 6, SJR: 0.174, CiteScore: 0)
Advances in Parasitology     Full-text available via subscription   (Followers: 5, SJR: 1.579, CiteScore: 4)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.461, CiteScore: 1)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 10)
Advances in Pharmacology     Full-text available via subscription   (Followers: 16, SJR: 1.536, CiteScore: 3)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.574, CiteScore: 1)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.109, CiteScore: 1)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19, SJR: 0.791, CiteScore: 2)
Advances in Psychology     Full-text available via subscription   (Followers: 59)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6, SJR: 0.371, CiteScore: 1)
Advances in Radiation Oncology     Open Access   (SJR: 0.263, CiteScore: 1)
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.101, CiteScore: 0)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 5)
Advances in Space Research     Full-text available via subscription   (Followers: 386, SJR: 0.569, CiteScore: 2)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Surgery     Full-text available via subscription   (Followers: 10, SJR: 0.555, CiteScore: 2)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 30, SJR: 2.208, CiteScore: 4)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 17)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 2.262, CiteScore: 5)
Advances in Water Resources     Hybrid Journal   (Followers: 46, SJR: 1.551, CiteScore: 3)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 1.117, CiteScore: 3)
Aerospace Science and Technology     Hybrid Journal   (Followers: 338, SJR: 0.796, CiteScore: 3)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.42, CiteScore: 2)
African J. of Emergency Medicine     Open Access   (Followers: 6, SJR: 0.296, CiteScore: 0)
Ageing Research Reviews     Hybrid Journal   (Followers: 10, SJR: 3.671, CiteScore: 9)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 438, SJR: 1.238, CiteScore: 3)
Agri Gene     Hybrid Journal   (SJR: 0.13, CiteScore: 0)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 15, SJR: 1.818, CiteScore: 5)
Agricultural Systems     Hybrid Journal   (Followers: 31, SJR: 1.156, CiteScore: 4)
Agricultural Water Management     Hybrid Journal   (Followers: 43, SJR: 1.272, CiteScore: 3)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 1)
Agriculture and Natural Resources     Open Access   (Followers: 2)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 56, SJR: 1.747, CiteScore: 4)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.589, CiteScore: 3)
Air Medical J.     Hybrid Journal   (Followers: 6, SJR: 0.26, CiteScore: 0)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.19, CiteScore: 0)
Alcohol     Hybrid Journal   (Followers: 11, SJR: 1.153, CiteScore: 3)
Alcoholism and Drug Addiction     Open Access   (Followers: 9)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.604, CiteScore: 3)
Alexandria J. of Medicine     Open Access   (Followers: 1, SJR: 0.191, CiteScore: 1)
Algal Research     Partially Free   (Followers: 10, SJR: 1.142, CiteScore: 4)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.504, CiteScore: 1)
Allergology Intl.     Open Access   (Followers: 5, SJR: 1.148, CiteScore: 2)
Alpha Omegan     Full-text available via subscription   (SJR: 3.521, CiteScore: 6)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 9, SJR: 0.201, CiteScore: 1)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 50, SJR: 4.66, CiteScore: 10)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 4, SJR: 1.796, CiteScore: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 4, SJR: 1.108, CiteScore: 3)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 6)
American Heart J.     Hybrid Journal   (Followers: 50, SJR: 3.267, CiteScore: 4)
American J. of Cardiology     Hybrid Journal   (Followers: 51, SJR: 1.93, CiteScore: 3)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 44, SJR: 0.604, CiteScore: 1)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 10)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, SJR: 1.524, CiteScore: 3)
American J. of Human Genetics     Hybrid Journal   (Followers: 32, SJR: 7.45, CiteScore: 8)
American J. of Infection Control     Hybrid Journal   (Followers: 26, SJR: 1.062, CiteScore: 2)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 34, SJR: 2.973, CiteScore: 4)
American J. of Medicine     Hybrid Journal   (Followers: 43)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3, SJR: 1.967, CiteScore: 2)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 201, SJR: 2.7, CiteScore: 4)
American J. of Ophthalmology     Hybrid Journal   (Followers: 61, SJR: 3.184, CiteScore: 4)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5, SJR: 0.265, CiteScore: 0)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.289, CiteScore: 1)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, CiteScore: 1)
American J. of Pathology     Hybrid Journal   (Followers: 27, SJR: 2.139, CiteScore: 4)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 27, SJR: 2.164, CiteScore: 4)
American J. of Surgery     Hybrid Journal   (Followers: 37, SJR: 1.141, CiteScore: 2)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.767, CiteScore: 1)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 6)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.144, CiteScore: 3)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 63, SJR: 0.138, CiteScore: 0)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 15, SJR: 0.411, CiteScore: 1)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 3, SJR: 0.277, CiteScore: 0)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription  
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 5, SJR: 4.849, CiteScore: 10)
Analytica Chimica Acta     Hybrid Journal   (Followers: 39, SJR: 1.512, CiteScore: 5)
Analytical Biochemistry     Hybrid Journal   (Followers: 175, SJR: 0.633, CiteScore: 2)
Analytical Chemistry Research     Open Access   (Followers: 10, SJR: 0.411, CiteScore: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 2)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 23, SJR: 0.683, CiteScore: 2)
Angiología     Full-text available via subscription   (SJR: 0.121, CiteScore: 0)
Angiologia e Cirurgia Vascular     Open Access   (Followers: 1, SJR: 0.111, CiteScore: 0)

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Journal Cover
Acta Astronautica
Journal Prestige (SJR): 0.758
Citation Impact (citeScore): 2
Number of Followers: 395  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0094-5765
Published by Elsevier Homepage  [3163 journals]
  • Comparison of the space bubble detector response to space-like neutron
           spectra and high energy protons
    • Authors: Alexander Miller; Rachid Machrafi; Eric Benton; Hisashi Kitamura; Satoshi Kodaira
      Pages: 1 - 6
      Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Alexander Miller, Rachid Machrafi, Eric Benton, Hisashi Kitamura, Satoshi Kodaira
      To compare the response to high energy neutrons and protons of the space bubble detectors in use aboard the International Space Station (ISS), three series of experiments were conducted with high energy protons and neutrons. The first series of experiments was conducted with high-energy neutrons in the energy range expected for neutrons encountered during space flight (0.6–800 MeV) at the Los Alamos Neutron Science Center (LANSCE) using the spallation neutron source. The second series was conducted with high energy protons from 30 to 70 MeV using the cyclotron at the National Institute of Radiological Science NIRS in Japan, and the third series of experiments was performed with high energy protons from 60 to 230 MeV at the ProCure proton therapy facility, Oklahoma, USA. The bubble detectors were exposed to different fluences in different experiments and the number of bubbles was counted using a bubble detector reader. The proton response of the bubble detector (sensitivity), as a function of energy, was determined and compared to the neutron sensitivity. In addition, to adjust the neutron sensitivity of the bubble detector determined in an AmBe field, a calibration factor was obtained for space applications.

      PubDate: 2018-06-03T03:37:43Z
      DOI: 10.1016/j.actaastro.2018.05.035
      Issue No: Vol. 151 (2018)
  • Experimental study on a rotating detonation combustor with an axial-flow
    • Authors: Shengbing Zhou; Hu Ma; Yuan Ma; Changsheng Zhou; Daokun Liu; Shuai Li
      Pages: 7 - 14
      Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Shengbing Zhou, Hu Ma, Yuan Ma, Changsheng Zhou, Daokun Liu, Shuai Li
      The research on rotating detonation turbine engine is attracting much attention in recent years. In this study, experiments have been performed on a structure combining a rotating detonation combustor and an axial-flow turbine to investigate the propagation characteristics of the hydrogen-air rotating detonation wave. The stable rotating detonation wave is successfully initiated using the spark plug and pre-detonator, and there is still a velocity deficit of about 20% relative to the Chapmane-Jouguet value. There is a formation process for the stable detonation wave, and the formation time for the pre-detonator is far less than the spark plug, however the final state is independent on the ignition device. The rotating detonation wave successively appears the two-wave state with a same direction, the two-peak wave state, and the state of strong–weak alternation during the formation process. Finally, only one stable detonation wave is formed in the chamber and propagates until the operation off.

      PubDate: 2018-06-03T03:37:43Z
      DOI: 10.1016/j.actaastro.2018.05.047
      Issue No: Vol. 151 (2018)
  • Performance evaluation and comparison of electricity generation systems
           based on single- and two-stage thermoelectric generator for hypersonic
    • Authors: Kunlin Cheng; Duo Zhang; Jiang Qin; Silong Zhang; Wen Bao
      Pages: 15 - 21
      Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Kunlin Cheng, Duo Zhang, Jiang Qin, Silong Zhang, Wen Bao
      Thermoelectric generator (TEG) is a promising electricity generation technology distinguished by a direct thermoelectric conversion. The single- and two-stage TEG model, the heat source of which was the combustion heat dissipation, were developed to predict and compare the power generation performance on hypersonic vehicles at different inlet temperatures of heating channel, T fh0 . The distributions of the temperature and thermoelectric figure of merit (ZT value) were described by diagrams. Besides, some methods for performance enhancement were discussed. The results indicate that the single-stage TEG has an advantage of the maximum power density, and the two-stage TEG shows a higher conversion efficiency at the same T fh0 . The maximum power density of 16.53 kW/m2 is achieved by the single-stage thermoelectric generator. The optimal conversion efficiency is 10.78%, obtained by the two-stage TEG. Both the maximum power density and corresponding conversion efficiency increase with the inlet temperature of heating channel. In addition, the two-stage TEG has a greater potential for improving performance, by means of multiple thermoelectric materials in their optimal temperature ranges.

      PubDate: 2018-06-03T03:37:43Z
      DOI: 10.1016/j.actaastro.2018.05.033
      Issue No: Vol. 151 (2018)
  • Angular momentum management strategy of the FengYun-4 meteorological
    • Authors: Yiwu Liu; Zhuhua Si; Liang Tang; Shoulei Chen
      Pages: 22 - 31
      Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Yiwu Liu, Zhuhua Si, Liang Tang, Shoulei Chen
      Solar radiation torque has a great impact on Chinese new generation geostationary meteorological satellite FengYun-4 since its single winged solar array configuration. Daily accumulation in angular momentum stored in reaction wheels may increase about 30Nms, and should be unloaded via bipropellant thrusters during a daily 15-min housekeeping period. How to prevent zero-crossing and saturation of wheels, how to reduce the operation speed range of wheels, and how to ensure the service continuity if any one of wheels fails are the problems to be faced. In addition, both the uncertainty of thruster torque and the variability of solar radiation during all the life span may go against with the automaticity of angular momentum management. In this paper, a null-space-based momentum management method is presented, upon which the angular momentum is managed by null motion control while service and dumped during the housekeeping period. In-flight and numerical simulation results demonstrate the reliability and validity of this strategy.

      PubDate: 2018-06-03T03:37:43Z
      DOI: 10.1016/j.actaastro.2018.05.031
      Issue No: Vol. 151 (2018)
  • Lunar orbit dynamics and maneuvers for Lunisat missions
    • Authors: Mauro Pontani; Riccardo Di Roberto; Filippo Graziani
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Mauro Pontani, Riccardo Di Roberto, Filippo Graziani
      Lunisat represents a next-generation microsatellite aimed at orbiting the Moon, and equipped with dispensers for the release of nanosatellites. This research is focused on the orbital dynamics of both the main microsatellite and the nanosatellites after release. Due to the irregular concentrations of mass in the Moon, low altitude, near-circular lunar orbits are affected by a considerable number of harmonics of the Moon gravitational field. Nonsingular equinoctial orbit elements are employed for orbit propagations, in conjunction with numerical averaging, which is a numerical technique that allows substantial computational improvements. The dynamical model considers a large number of harmonics of the lunar gravitational field, as well as the Earth and Sun perturbing influence as third bodies. Low-altitude lunar satellites turn out to impact the lunar surface after a few weeks or months. In case of an unsatisfactory lifetime, two simple orbit maintenance strategies are evaluated, together with the related propellant budget. Nanosatellites will be released from Lunisat by means of springs. The orbit of each nanosatellite depends on the release conditions, i.e. the relative velocity magnitude and direction. This work investigates the nanosatellite lifetimes as functions of these conditions. Lastly, minimum-time low-thrust transfers for reducing the orbit altitude are investigated, both for nanosatellite release and for the conclusive phase of the Lunisat mission, which finally terminates with the impact on the lunar surface.

      PubDate: 2018-05-31T03:35:07Z
      DOI: 10.1016/j.actaastro.2018.05.015
      Issue No: Vol. 149 (2018)
  • A maximal-reward preliminary planning for multi-debris active removal
           mission in LEO with a greedy heuristic method
    • Authors: Jianan Yang; Yu Hen Hu; Yong Liu; Quan Pan
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Jianan Yang, Yu Hen Hu, Yong Liu, Quan Pan
      An active multi-debris removal mission planning algorithm for low Earth orbit (LEO) debris removal is presented. We assume that a space platform carrying multiple debris-deorbiting nano-satellites will be launched to carry out the debris-removal mission. This platform travels from one debris object to the next using a drift-orbit-transfer strategy. Each debris is assigned a reward value reflecting potential collision risk reductions if the debris is deorbited. The objective of mission planning is to determine an ordering of debris to be deorbited that maximizes the total reward due to debris removal subject to the constraints of (a) the total amount of velocity change for orbit transfer, (b) the total duration of the debris removal mission, and (c) the number of deorbiting nano-satellites carried on board the platform. In this work, a new approach is taken to approximate the response curve of drift-orbit transfers between each debris pair using a numerically interpolated continuous curve. An optimal orbit transfer strategy then is adopted to minimizes the sum of relative Δ v consumption and relative transfer duration. The task of multi-debris removal mission planning is formulated as a combinatorial tree search discrete optimization problem using this optimal orbit transfer cost estimate. A greedy heuristic with polynomial time complexity is proposed to select the next debris to deorbit that maximizes the reward-to-cost ratio. The effectiveness of this novel approach is demonstrated using real-world Iridium 33 debris cloud data. It is observed that this algorithm delivers superior performance while consuming a small fraction of computing time compared to state of the art mission planning algorithms.

      PubDate: 2018-05-31T03:35:07Z
      DOI: 10.1016/j.actaastro.2018.05.040
      Issue No: Vol. 149 (2018)
  • Exogeoconservation: Protecting geological heritage on celestial bodies
    • Authors: J.J. Matthews; S. McMahon
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Jack J. Matthews, Sean McMahon
      Geoconservation is an increasingly widely adopted theoretical, practical and administrative approach to the protection of geological and geomorphological features of special scientific, functional, historic, cultural, aesthetic, or ecological value. Protected sites on Earth include natural rocky outcrops, shorelines, river banks, and landscapes, as well as human-made structures such as road cuts and quarries exposing geological phenomena. However, geoconservation has rarely been discussed in the context of other rocky and icy planets, rings, moons, dwarf planets, asteroids, or comets, which present extraordinarily diverse, beautiful, and culturally, historically and scientifically important geological phenomena. Here we propose to adapt geoconservation strategies for protecting the geological heritage of these celestial bodies, and introduce the term ‘exogeoconservation’ and other associated terms for this purpose. We argue that exogeoconservation is acutely necessary for the scientific exploration and responsible stewardship of celestial bodies, and suggest how this might be achieved and managed by means of international protocols. We stress that such protocols must be sensitive to the needs of scientific, industrial, and other human activities, and not unduly prohibitive. However, with space exploration and exploitation likely to accelerate in coming decades, it is increasingly important that an internationally agreed, holistic framework be developed for the protection of our common ‘exogeoheritage’.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.034
      Issue No: Vol. 149 (2018)
  • Data authentication, integrity and confidentiality mechanisms for
           federated satellite systems
    • Authors: Olga von Maurich; Alessandro Golkar
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Olga von Maurich, Alessandro Golkar
      This work addresses a critical topic in federated satellites development: the lack of trust between stakeholders that would prevent any stakeholder joining a satellite federation owned and operated by multiple parties. A characterisation of security needs for federated satellite systems is proposed, showing that in order for a federation to offer an environment for a beneficial cooperation, a notion of identity, both user identity and data authentication, has to be introduced, and stakeholders' security requirements have to be satisfied. This paper presents a public key infrastructure (PKI) based protocol for addressing stakeholders' security requirements and ensuring data authentication, integrity and confidentiality in data transfer operations within satellite federations. The performance and cost overheads of the proposed security protocol are first characterised with an experimental implementation on a Raspberry Pi 2 platform, used as a representative proxy testbed of commercial off-the-shelf avionics for small satellites, and then with a benchmark on a range of CPUs to analyse which platforms achieve set performance goals with radio-based and laser-based communications. Recommendations for implementing security mechanisms in federated satellite systems are thus derived.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.003
      Issue No: Vol. 149 (2018)
  • Onset of detonation in hydrogen-air mixtures due to shock wave reflection
           inside a combustion chamber
    • Authors: N.N. Smirnov; O.G. Penyazkov; K.L. Sevrouk; V.F. Nikitin; L.I. Stamov; V.V. Tyurenkova
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): N.N. Smirnov, O.G. Penyazkov, K.L. Sevrouk, V.F. Nikitin, L.I. Stamov, V.V. Tyurenkova
      Hydrogen fuel, as for now, is the most energy efficient and clean fuel for aviation engines. At present time RAM engines based on chemical burning of fuels and accelerating exhaust gases practically reached the top of their efficiency in terms of specific impulse. New schemes are under development. As it is known, complex geometry of combustion chambers could bring to compression waves focusing and changing the mode of flame propagation from slow combustion to detonation. Keeping this process under control is of major importance for developing new generation of engines. The paper presents results of numerical and experimental investigation of mixture ignition and detonation onset in shock wave reflected from inside a wedge. Comparison of numerical and experimental results made it possible to validate the developed 3-D transient mathematical model of chemically reacting gas mixture flows incorporating hydrogen – air mixtures. Kinetic schemes were improved based on comparison of numerical and experimental results. A tool was developed making it possible to set a criterion for obtaining either safe combustion regime, or transition to detonation regime in shock wave focusing.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.024
      Issue No: Vol. 149 (2018)
  • Being a father during the space career: Retired cosmonauts' involvement
    • Authors: Phyllis J. Johnson; Peter Suedfeld; Vadim I. Gushin
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Phyllis J. Johnson, Peter Suedfeld, Vadim I. Gushin
      The space career requires numerous absences from the cosmonaut's family during training and spaceflight. Such absences mean missing important milestones, events, and celebrations in the lives of their children. This study assesses retired cosmonauts' views of actual and desired involvement with their children during their spaceflight career. The Father Involvement Scale (adapted from Finley & Schwartz, 2004; Hawkins et al., 2002), translated into Russian, was answered by 17 retired cosmonauts. The 20 domains in the scale included 10 Expressive (e.g., intellectual, emotional, social, and spiritual development; sharing activities and interests) and 10 Instrumental (e.g., providing income, being protective, discipline, school/homework, and developing responsibility, independence, and competence). The cosmonauts' ratings of actual involvement with their children's lives was between Sometimes involved and Often involved (M = 3.66, SD = 0.42). None of the cosmonauts indicated Never involved for any of the Expressive domains or for seven of the ten Instrumental domains. Within the Expressive domains, the majority of cosmonauts said they were “often” involved in their child's spiritual development and in sharing activities/interests. Within the Instrumental domains, they were “often” involved in discipline and “always” involved in providing income. The areas in which they wished they had been “much more involved” than they had been were Expressive, rather than Instrumental: intellectual, spiritual, and physical development; sharing activities/interests, and companionship. This is the first study to measure retrospective assessments of father involvement during spaceflight careers. Space agencies should consider how Family Support personnel can enhance the parental involvement of future spacefarers.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.028
      Issue No: Vol. 149 (2018)
  • Numerical and experimental investigation on the influence of inlet
           contraction ratio for a rocket-based combined cycle engine
    • Authors: Zhengze Zhang; Peijin Liu; Fei Qin; Lei Shi; Yajun Wang; Chao Huo
      Pages: 1 - 10
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Zhengze Zhang, Peijin Liu, Fei Qin, Lei Shi, Yajun Wang, Chao Huo
      The influences of inlet contraction ratio on both the inlet and combustor of the rocket-based combined cycle engine are investigated in this paper by experimental and numerical approaches. A translating spike was employed to simulate the inlet counter pressure in the wind tunnel experiment. Steady-state pressure distributions were recorded and schlieren photos were obtained simultaneously. The combined numerical-experimental results show that the increased inlet contraction ratio always results in the increasing of the compression ratio and capability of anti-counter pressure, while its impact on the mass flow coefficient is negligible. Besides, the reactive numerical results show that the coefficients of inlet drag and combustor thrust increase with the increasing of the inlet contraction ratio, while the nozzle thrust coefficient demonstrates an opposite trend. These suggest that the selection of an appropriate inlet contraction ratio can effectively improve the total thrust coefficient of the engine, while the appropriate inlet contraction ratio is to be set to the minimum that satisfies the robust combustion requirement.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.017
      Issue No: Vol. 149 (2018)
  • Continuous discharge in micro ablative pulsed plasma thrusters
    • Authors: Zhiwen Wu; Guorui Sun
      Pages: 11 - 14
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Zhiwen Wu, Guorui Sun
      The mechanism of continuous discharge in micro ablative pulsed plasma thrusters has always been ignored. A series of experiments on discharge completion rate were conducted, and theoretical analyses were performed to understand the results. These results showed that as initial voltage decreased to a certain value, a portion of energy was not released in a short time, which caused overall efficiency to greatly decrease. As the initial voltage decreased sequentially, this phenomenon occurred more frequently. This study provides a reference for high-frequency micro ablative pulsed plasma thrusters.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.026
      Issue No: Vol. 149 (2018)
  • Experimental investigation on the surface wave characteristics of conical
           liquid film
    • Authors: Zhongtao Kang; Xiangdong Li; Xiongbing Mao
      Pages: 15 - 24
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Zhongtao Kang, Xiangdong Li, Xiongbing Mao
      The disintegration of the liquid sheet is due to the growth of the unstable surface wave. Research on the surface wave characteristics mainly uses the linear stability analysis, and the surface wave characteristics, for example the frequency and wave length of the surface wave, have not been analyzed well experimentally. In the present study, the proper orthogonal decomposition is adopted to analyze the instantaneous spray images and the extracted surface waves on the interface of the gas and liquid. The wavelength and frequency of the surface wave are obtained, and the influence of the injector mass flow rate is investigated. The results show that the spray pattern moves from onion stage to tulip stage and fully developed wavy cone stage with the increase of liquid mass flow rate. In the tulip stage, the wave frequency decreases slightly and then increases with the increase of liquid mass flow rate. On the contrary, the wavelength increases gradually with the increase of liquid mass flow rate and then decreases slightly. This variation trend is caused by the competition effect of the film thickness and the axial film velocity. The decrease of film thickness decreases the wave frequency and increases the wavelength, while the increase of the axial film velocity increases the wave frequency and decreases the wavelength. In the fully developed wavy cone stage, the wave frequency increases gradually with the increase of liquid mass flow rate. And the bandwidth of the surface wave frequency increases gradually, which means that the leading role of the dominant surface wave is weakened and the conical film is dominated by surface waves with multiple frequencies. The wavelength decreases with the increase of liquid mass flow rate because of the significant increased axial film velocity.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.030
      Issue No: Vol. 149 (2018)
  • Natural formation flying on quasi-halo orbits in the photogravitational
           circular restricted three-body problem
    • Authors: Tong Luo; Ming Xu; Yunfeng Dong
      Pages: 35 - 46
      Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149
      Author(s): Tong Luo, Ming Xu, Yunfeng Dong
      Formation flying near a libration point is an effective method of the multi-point in-situ detection of deep-space environment and the high resolution observation of astronomy etc. This paper proposes a novel numerical searching method based on ergodic Poincaré mappings to seek natural formation flying on quasi-halo orbits in a photogravitational circular restricted three-body problem (PCR3BP). The reduced Hamiltonian system using the Lie series method gives a qualitative description of the phase space near the libration points. Then, an algorithm to return numerical solutions of invariant tori back to the synodic reference coordinate is presented. This research proposes a new type of Poincaré mapping from center manifolds of quasi-halo orbits onto the defined characteristic indexes in formation flying. Appropriate orbit groups, including two quasi-halo orbits, a halo orbit and a quasi-halo orbit, or multiple quasi-halo orbits, are all feasible for formation flying through numerically ergodic searching. Finally, the relative trajectory is considered unstable and a control scheme is required in practical formation flying.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.027
      Issue No: Vol. 149 (2018)
  • OCEANUS: A high science return Uranus orbiter with a low-cost instrument
    • Authors: C.M. Elder; A.M. Bramson; L.W. Blum; H.T. Chilton; A. Chopra; C. Chu; A. Das; A.B. Davis; A. Delgado; J. Fulton; L.M. Jozwiak; A. Khayat; M.E. Landis; J.L. Molaro; M. Slipski; S. Valencia; J. Watkins; C.L. Young; C.J. Budney; K.L. Mitchell
      Pages: 1 - 11
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): C.M. Elder, A.M. Bramson, L.W. Blum, H.T. Chilton, A. Chopra, C. Chu, A. Das, A.B. Davis, A. Delgado, J. Fulton, L.M. Jozwiak, A. Khayat, M.E. Landis, J.L. Molaro, M. Slipski, S. Valencia, J. Watkins, C.L. Young, C.J. Budney, K.L. Mitchell
      Ice-giant-sized planets are the most common type of observed exoplanet, yet the two ice giants in our own solar system (Uranus and Neptune) are the least explored class of planet, having only been observed through ground-based observations and a single flyby each by Voyager 2 approximately 30 years ago. These single flybys were unable to characterize the spatial and temporal variability in ice giant magnetospheres, some of the most odd and intriguing magnetospheres in the solar system. They also offered only limited constraints on the internal structure of ice giants; understanding the internal structure of a planet is important for understanding its formation and evolution. The most recent planetary science Decadal Survey by the U.S. National Academy of Sciences, “Vision and Voyages for Planetary Science in the Decade 2013–2022,” identified the ice giant Uranus as the third highest priority for a Flagship mission in the decade 2013–2022. However, in the event that NASA or another space agency is unable to fly a Flagship-class mission to an ice giant in the next decade, this paper presents a mission concept for a focused, lower cost Uranus orbiter called OCEANUS (Origins and Composition of the Exoplanet Analog Uranus System). OCEANUS would increase our understanding of the interior structure of Uranus, its magnetosphere, and how its magnetic field is generated. These goals could be achieved with just a magnetometer and the spacecraft's radio system. This study shows that several of the objectives outlined by the Decadal Survey, including one of the two identified as highest priority, are within reach for a New-Frontiers-class mission.

      PubDate: 2018-05-31T03:35:07Z
      DOI: 10.1016/j.actaastro.2018.04.019
      Issue No: Vol. 148 (2018)
  • Shock wave structures in the wake of sonic transverse jet into a
           supersonic crossflow
    • Authors: Chang-hai Liang; Ming-bo Sun; Yuan Liu; Yi-xin Yang
      Pages: 12 - 21
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Chang-hai Liang, Ming-bo Sun, Yuan Liu, Yi-xin Yang
      This study experimentally and numerically investigated the flow physics of a sonic transverse gaseous jet under a Ma = 2.95 supersonic crossflow. NPLS (Nanoparticle-based Planar Laser Scattering) and oil flow techniques were combined to achieve experimental visualization, while RANS (Reynolds-averaged Navier-Stokes) model was used to carry out the numerical simulation. Under the supersonic crossflow with jet-to-crossflow momentum flux ratio (J) of 7.7, the typical structures, including a bow shock, a barrel shock, horseshoe vortex, and separation zones, were clearly observed by the NPLS techniques. V-shape separation bubbles and V-shape collision shocks were identified based on the oil-flow results. Detailed flow fields around the V-shape separation bubble were then revealed by numerical calculations. It is shown that the collision shock induced V-shape separation bubbles can further affect the Mach disk, the reflected shock and the barrel shock. The reflected shock deflects the collision shock toward the two flanks. The collision shock intersects with the barrel shock, influencing the shape of the Mach disk. In addition, the interaction between the reflected shock and the wall leads to the velocity slip in the near-wall region.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.009
      Issue No: Vol. 148 (2018)
  • Conceptual Moon imaging micro/nano-satellite design optimization under
    • Authors: Xingzhi Hu; Yong Zhao; Xiaoqian Chen; Valerio Lattarulo
      Pages: 22 - 31
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Xingzhi Hu, Yong Zhao, Xiaoqian Chen, Valerio Lattarulo
      Low-cost Moon imaging micro/nano-satellites have been receiving much attention from the engineering community. The reliability-based robust design optimization (RBRDO) of these weight/size/power constrained satellites is crucial. In this study, the configuration of this conceptual design problem considering uncertainty is analyzed and the interdisciplinary relations are described. Discipline models including orbit, payload, propulsion, and communication are mainly discussed. A new RBRDO approach to lunar micro/nano-satellite system design is presented, involving dimension reduction, dynamic response surface, system decoupling, and multiobjective alliance search. The optimization goal includes payload cost-effective ratio and satellite mass, and five reliability constraints are considered including satellite installation volume and battery cycles. Through identifying a dominant active subspace for high-dimensional inputs, the in-loop uncertainty quantification is greatly accelerated by about two orders of magnitude. A smooth and uniformly distributed Pareto front is therefore obtained to provide beneficial Pareto-optimal solutions, which indicates that the orbit altitude gathers around 200 km and the mission cycle is nearly 2.4 years. An optimal trade-off design has the minimum satellite mass of 8.95 kg and smaller cost-effective ratio. Compared with the deterministic optimization, the RBRDO approach is preferable for designing Moon imaging micro/nano-satellites of high reliability and robustness.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.017
      Issue No: Vol. 148 (2018)
  • Investigation of combustion characteristics in a scramjet combustor using
           a modified flamelet model
    • Authors: Guoyan Zhao; Mingbo Sun; Hongbo Wang; Hao Ouyang
      Pages: 32 - 40
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Guoyan Zhao, Mingbo Sun, Hongbo Wang, Hao Ouyang
      In this study, the characteristics of supersonic combustion inside an ethylene-fueled scramjet combustor equipped with multi-cavities were investigated with different injection schemes. Experimental results showed that the flames concentrated in the cavity and separated boundary layer downstream of the cavity, and they occupied the flow channel further enhancing the bulk flow compression. The flame structure in distributed injection scheme differed from that in centralized injection scheme. In numerical simulations, a modified flamelet model was introduced to consider that the pressure distribution is far from homogenous inside the scramjet combustor. Compared with original flamelet model, numerical predictions based on the modified model showed better agreement with the experimental results, validating the reliability of the calculations. Based on the modified model, the simulations with different injection schemes were analysed. The predicted flame agreed reasonably with the experimental observations in structure. The CO masses were concentrated in cavity and subsonic region adjacent to the cavity shear layer leading to intense heat release. Compared with centralized scheme, the higher jet mixing efficiency in distributed scheme induced an intense combustion in posterior upper cavity and downstream of the cavity. From streamline and isolation surfaces, the combustion at trail of lower cavity was depressed since the bulk flow downstream of the cavity is pushed down.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.005
      Issue No: Vol. 148 (2018)
  • Uncertainty dynamic theoretical analysis on ceramic thermal protection
           system using perturbation method
    • Authors: Jie Huang; Weixing Yao; Piao Li
      Pages: 41 - 47
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Jie Huang, Weixing Yao, Piao Li
      A two degree-of-freedom uncertainty dynamic theoretical model under the acoustic and base excitations was presented to analyze the uncertainty dynamic behaviors of thermal protection system (TPS) and the uncertainty dynamic strength of strain-isolation-pad (SIP). The tile and SIP are both simplified as the combination of a mass point, a linear spring and a damping element, and all the dynamic parameters obey the normal distribution. The probability distributions of responses were derived from adopting the perturbation method. The difference method is used to analyze the sensitivity of the mean responses to random parameters, and the reasonable sensitivity values are obtained under a difference step which is equal to the standard deviation of the random parameter. The probability distributions calculated by the uncertainty theoretical model match well with the Monte Carlo numerical results, so the accuracy of the uncertainty dynamic theoretical model is verified. The researches in this paper provide a theoretical foundation for studying the uncertainty dynamic behaviors of TPS, analyzing uncertainty dynamic strength of SIP and intensifying the integrity and security of TPS.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.027
      Issue No: Vol. 148 (2018)
  • Laplace ℓ1 Huber based cubature Kalman filter for attitude
           estimation of small satellite
    • Authors: Lu Cao; Dong Qiao; Xiaoqian Chen
      Pages: 48 - 56
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Lu Cao, Dong Qiao, Xiaoqian Chen
      This paper offers a solution to the attitude estimation of small satellite with the existence of model error and heavy-tailed noise, which is referred as to the Laplace ℓ1 Huber Based Kalman filter (ℓ1-HBKF). It employs the Laplace distribution and Huber based method to update the measurement covariance to deal with different types of model error or heavy-tailed noise for robust design. Then, the majorization minimization approach is discussed to improve the estimation accuracy by an iterative algorithm. In addition, the proposed ℓ1-HBKF is implemented in the Kalman filtering framework and is further extended by the strategy of fifth-degree cubature rule for high accuracy. Finally, the attitude estimation of small satellite is simulated and compared with conventional cubature Kalman filter (CKF), which can prove the accuracy and robustness of the proposed methods for the attitude estimation with low precision sensors.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.020
      Issue No: Vol. 148 (2018)
  • Performance evaluation of regenerative cooling/film cooling for
           hydrocarbon fueled scramjet engine
    • Authors: Jingying Zuo; Silong Zhang; Jiang Qin; Wen Bao; Naigang Cui
      Pages: 57 - 68
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Jingying Zuo, Silong Zhang, Jiang Qin, Wen Bao, Naigang Cui
      Thermal protection is considered to be a significant challenge for scramjet engine. In this paper, a combined cooling method which combines film cooling (F.C.) with regenerative cooling (R.C.) instead of single regenerative cooling for hydrocarbon fueled scramjet engine by using gaseous hydrocarbon fuel coming out of the cooling channel exit as film coolant has been proposed to increase the engine's flight Mach number without bringing extra fuel on board. One-dimensional (1-D) model of the combined cooling in terms of supersonic combustion in combustor and cracking reaction in regenerative cooling channels has been built and validated in order to evaluate its performance. The calculation results indicate that the engine wall temperature can be reduced significantly with R.C./F.C. and the flight Mach number of engine can be increased by nearly 8% under the stoichiometric fuel flow rate when material limit of the engine wall is set to be 1300 K. It is found that the effect of film inlet temperature on the cooling performance can be ignored because of the high total temperature of main flow, while the flow direction inside the cooing channel will have significant effects on the cooling performance of R.C./F.C.. The heat flux imposed on the engine wall is less uniform with “parallel flow” inside the cooling channel and the cooling performance is better and more sensitive to the change of film injection position under this condition. In addition, the cooling performance of R.C./F.C. present a very slight change when the number of the slots stays at a very low value and 2–3 film slots may be more practical and useful for the hydrocarbon fueled scramjet engine.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.037
      Issue No: Vol. 148 (2018)
  • Dynamic analysis of lunar lander during soft landing using explicit finite
           element method
    • Authors: Guang Zheng; Hong Nie; Jinbao Chen; Chuanzhi Chen; Heow Pueh Lee
      Pages: 69 - 81
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Guang Zheng, Hong Nie, Jinbao Chen, Chuanzhi Chen, Heow Pueh Lee
      In this paper, the soft-landing analysis of a lunar lander spacecraft under three loading case was carried out in ABAQUS, using the Explicit Finite Element method. To ensure the simulation result's accuracy and reliability, the energy and mass balance criteria of the model was presented along with the theory and calculation method, and the results were benchmarked with other software (LS-DYNA) to get a validated model. The results from three loading case showed that the energy and mass of the models were conserved during soft landing, which satisfies the energy and mass balance criteria. The overloading response, structure steady state, and the crushing stroke of this lunar lander all met the design requirements of the lunar lander. The buffer energy-absorbing properties in this model have a good energy-absorbing capability, in which up to 84% of the initial energy could be dissipated. The design parameters of the model could guide the design of future manned landers or larger lunar landers.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.014
      Issue No: Vol. 148 (2018)
  • Orbit estimation using a horizon detector in the presence of uncertain
           celestial body rotation and geometry
    • Authors: Amir Shakouri; Mahdi Hazrati Azad; Nima Assadian
      Pages: 82 - 88
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Amir Shakouri, Mahdi Hazrati Azad, Nima Assadian
      This paper presents an orbit estimation using non-simultaneous horizon detector measurements in the presence of uncertainties in the celestial body rotational velocity and its geometrical characteristics. The celestial body is modeled as a tri-axial ellipsoid with a three-dimensional force field. The non-simultaneous modelling provides the possibility to consider the time gap between horizon measurements. An unscented Kalman filter is used to estimate the spacecraft state variables and the geometric characteristics as well as the rotational velocity vector of the celestial body. A Monte-Carlo simulation is implemented to verify the results. Simulations showed that using non-simultaneous horizon vector measurements, the spacecraft state errors converge to zero even in the presence of an uncertain geometry and rotational velocity of the celestial body.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.021
      Issue No: Vol. 148 (2018)
  • Static and moving solid/gas interface modeling in a hybrid rocket engine
    • Authors: Alexandre Mangeot; Mame William-Louis; Philippe Gillard
      Pages: 89 - 98
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Alexandre Mangeot, Mame William-Louis, Philippe Gillard
      A numerical model was developed with CFD-ACE software to study the working condition of an oxygen-nitrogen/polyethylene hybrid rocket combustor. As a first approach, a simplified numerical model is presented. It includes a compressible transient gas phase in which a two-step combustion mechanism is implemented coupled to a radiative model. The solid phase from the fuel grain is a semi-opaque material with its degradation process modeled by an Arrhenius type law. Two versions of the model were tested. The first considers the solid/gas interface with a static grid while the second uses grid deformation during the computation to follow the asymmetrical regression. The numerical results are obtained with two different regression kinetics originating from ThermoGravimetry Analysis and test bench results. In each case, the fuel surface temperature is retrieved within a range of 5% error. However, good results are only found using kinetics from the test bench. The regression rate is found within 0.03 mm s−1 and average combustor pressure and its variation over time have the same intensity than the measurements conducted on the test bench. The simulation that uses grid deformation to follow the regression shows a good stability over a 10 s simulated time simulation.

      PubDate: 2018-05-02T17:12:21Z
      DOI: 10.1016/j.actaastro.2018.04.046
      Issue No: Vol. 148 (2018)
  • Design and deploying study of a new petal-type deployable solid surface
    • Authors: He Huang; Fu-Ling Guan; Liang-Lai Pan; Yan Xu
      Pages: 99 - 110
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): He Huang, Fu-Ling Guan, Liang-Lai Pan, Yan Xu
      Deployable solid surface reflector is still one of the most important ways to fulfill the ultra-high-accuracy and ultra-large-aperture reflector antennas. However the drawback of integrate stiffness is still a main problem for solid surface reflectors in the former research. To figure out this problem, a New Petal-type Deployable Solid Surface Antenna (NPDSSA) is developed in this study. A kind of drag springs are applied as linkages with adjacent petals to improve the integrate rigidity. The structural design is introduced and the geometric parameters are analyzed to find their effects on the rotation and package capacities. The software simulations and laboratory model tests are conducted to verify the deploying process of NPDSSA. Two models are employed to study the property of linkage butts and drag springs. It is indicated that model NPDSSA with the application of linkage butts and drag springs has better integrality and stability during the deploying. Finally it is concluded that NPDSSA is feasible for space applications.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.04.042
      Issue No: Vol. 148 (2018)
  • Thermal analysis of regenerative-cooled pylon in multi-mode rocket based
           combined cycle engine
    • Authors: Dekun Yan; Guoqiang He; Wenqiang Li; Duo Zhang; Fei Qin
      Pages: 121 - 131
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Dekun Yan, Guoqiang He, Wenqiang Li, Duo Zhang, Fei Qin
      Combining pylon injector with rocket is an effective method to achieve efficient mixing and combustion in the RBCC engine. This study designs a fuel pylon with active cooling structure, and numerically investigates the coupled heat transfer between active cooling process in the pylon and combustion in the combustor in different modes. Effect of the chemical reaction of the fuel on the flow, heat transfer and physical characteristics is also discussed. The numerical results present a good agreement with the experimental data. Results indicate that drastic supplementary combustion caused by rocket gas and secondary combustion caused by the fuel injection from the pylon result in severe thermal load on the pylon. Although regenerative cooling without cracking can reduce pylon's temperature below the allowable limit, a high-temperature area appears in the middle and nail section of the pylon due to the coolant's insufficient convective heat transfer coefficient. Comparatively, endothermic cracking can provide extra chemical heat sink for the coolant and low velocity contributes to prolong the reaction time to increase the heat absorption from chemical reaction, which further lowers and unifies the pylon surface temperature.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.04.038
      Issue No: Vol. 148 (2018)
  • Past and present engagement in space activities in Central and Eastern
    • Authors: Daniel Sagath; Maarten Adriaensen; Christina Giannopapa
      Pages: 132 - 140
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Daniel Sagath, Maarten Adriaensen, Christina Giannopapa
      Central and Eastern European (CEE) countries have been facing different cooperation models in the last fifty years regarding space policy and industrial activities. The period before the 1990s provided these countries with a strong heritage of expertise in space engagement which after the fall of the ‘Eastern Block’ offered the basis for cooperation with the other European countries and organisations. The way space policy in the CEE region was shaped during the early period and the way collaboration is conducted today have not been fully analysed. The objective of this paper is to provide a holistic analysis of the evolution of past and present developments of the CEE countries in space activities. The main focus of this paper is given to the Intercosmos period before the 1990s and following that, the integration process of these countries to the European Space Agency (ESA). Additionally, the CEE countries have been engaging in cooperation with other space agencies in Europe and outside. The countries also participate through the EU and its two flagship programmes Galileo and Copernicus amongst others. Furthermore, this paper provides an overview of the ESA accession process established in the early 2000s as ESA responded to the increasing interest of the CEE countries to engage in cooperation in the field of space. The comparison of both, historical and recent developments on CEE countries in space activities, indicates that CEE region has the basis for integrating in the European space sector. Participation in ESA and collaboration with other space faring nations is needed to ensure successful transformation of both their scientific and industrial basis as well as their governance, to the evolving space sector while utilizing the heritage obtained through the past engagements.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.04.048
      Issue No: Vol. 148 (2018)
  • Mathematical modeling and characteristic analysis for over-under turbine
           based combined cycle engine
    • Authors: Jingxue Ma; Juntao Chang; Jicheng Ma; Wen Bao; Daren Yu
      Pages: 141 - 152
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Jingxue Ma, Juntao Chang, Jicheng Ma, Wen Bao, Daren Yu
      The turbine based combined cycle engine has become the most promising hypersonic airbreathing propulsion system for its superiority of ground self-starting, wide flight envelop and reusability. The simulation model of the turbine based combined cycle engine plays an important role in the research of performance analysis and control system design. In this paper, a turbine based combined cycle engine mathematical model is built on the Simulink platform, including a dual-channel air intake system, a turbojet engine and a ramjet. It should be noted that the model of the air intake system is built based on computational fluid dynamics calculation, which provides valuable raw data for modeling of the turbine based combined cycle engine. The aerodynamic characteristics of turbine based combined cycle engine in turbojet mode, ramjet mode and mode transition process are studied by the mathematical model, and the influence of dominant variables on performance and safety of the turbine based combined cycle engine is analyzed. According to the stability requirement of thrust output and the safety in the working process of turbine based combined cycle engine, a control law is proposed that could guarantee the steady output of thrust by controlling the control variables of the turbine based combined cycle engine in the whole working process.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.04.050
      Issue No: Vol. 148 (2018)
  • Numerical analysis of air dissociation influence on spaceplane aerodynamic
    • Authors: Nikolay A. Elisov; Sergey A. Ishkov; Valentin G. Shakhov
      Pages: 153 - 162
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Nikolay A. Elisov, Sergey A. Ishkov, Valentin G. Shakhov
      Hypersonic flow is a very complex regime due to high values of velocity that causes air dissociation and ionization. This paper explores the influence of air dissociation on aircraft aerodynamic properties. The approach is the creation of a block-structured mesh by means of ICEM CFD and further set-up of Fluent solver. Aircraft aerodynamics properties were calculated for cases of perfect gas and non-equilibrium flow. Based on the results of the calculation, a comparison was made between obtained drag pressure coefficients, skin friction coefficients, drag coefficients, lift coefficients, lift-to-drag ratios and pitching moment coefficients.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.001
      Issue No: Vol. 148 (2018)
  • Experimental investigation on the effect of swirling flow on combustion
           characteristics and performance of solid fuel ramjet
    • Authors: Omer Musa; Li Weixuan; Chen Xiong; Gong Lunkun; Liao Wenhe
      Pages: 163 - 174
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Omer Musa, Li Weixuan, Chen Xiong, Gong Lunkun, Liao Wenhe
      Solid-fuel ramjet converts thermal energy of combustion products to a forward thrust without using any moving parts. Normally, it uses air intake system to compress the incoming air without swirler. A new design of swirler has been proposed and used in the current work. In this paper, a series of firing tests have been carried out to investigate the impact of using swirl flow on regression rate, combustion characteristics, and performance of solid-fuel ramjet engines. The influences of swirl intensity, solid fuel port diameter, and combustor length were studied and varied independently. A new technique for determining the time and space averaged regression rate of high-density polyethylene solid fuel surface after experiments has been proposed based on the laser scan technique. A code has been developed to reconstruct the data from the scanner and then used to obtain the three-dimensional distribution of the regression rate. It is shown that increasing swirl number increases regression rate, thrust, and characteristic velocity, and, decreases air-fuel ratio, corner recirculation zone length, and specific impulse. Using swirl flow enhances the flame stability meanwhile negatively affected on ignition process and specific impulse. Although a significant reduction of combustion chamber length can be achieved when swirl flow is used. Power fitting correlation for average regression rate was developed taking into account the influence of swirl number. Furthermore, varying port diameter and combustor length were found to have influences on regression rate, combustion characteristics and performance of solid-fuel ramjet.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.04.055
      Issue No: Vol. 148 (2018)
  • Integrated guidance and control for microsatellite real-time automated
           proximity operations
    • Authors: Ying Chen; Zhen He; Ding Zhou; Zhenhua Yu; Shunli Li
      Pages: 175 - 185
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Ying Chen, Zhen He, Ding Zhou, Zhenhua Yu, Shunli Li
      This paper investigates the trajectory planning and control of autonomous spacecraft proximity operations with impulsive dynamics. A new integrated guidance and control scheme is developed to perform automated close-range rendezvous for underactuated microsatellites. To efficiently prevent collision, a modified RRT* trajectory planning algorithm is proposed under this context. Several engineering constraints such as collision avoidance, plume impingement, field of view and control feasibility are considered simultaneously. Then, the feedback controller that employs a turn-burn-turn strategy with a combined impulsive orbital control and finite-time attitude control is designed to ensure the implementation of planned trajectory. Finally, the performance of trajectory planner and controller are evaluated through numerical tests. Simulation results indicate the real-time implementability of the proposed integrated guidance and control scheme with position control error less than 0.5 m and velocity control error less than 0.05 m/s. Consequently, the proposed scheme offers the potential for wide applications, such as on-orbit maintenance, space surveillance and debris removal.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.04.054
      Issue No: Vol. 148 (2018)
  • Failure tolerance strategy of space manipulator for large load carrying
    • Authors: Gang Chen; Bonan Yuan; Qingxuan Jia; Hanxu Sun; Wen Guo
      Pages: 186 - 204
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Gang Chen, Bonan Yuan, Qingxuan Jia, Hanxu Sun, Wen Guo
      During the execution of large load carrying tasks in long term service, there is a notable risk of space manipulator suffering from locked-joint failure, thus space manipulator should be with enough failure tolerance performance. A research on evaluating failure tolerance performance and re-planning feasible task trajectory for space manipulator performing large load carrying tasks is conducted in this paper. The effects of locked-joint failure on critical performance(reachability and load carrying capacity) of space manipulator are analyzed at first. According to the requirements of load carrying tasks, we further propose a new concept of failure tolerance workspace with load carrying capacity(FTWLCC) to evaluate failure tolerance performance, and improve the classic A* algorithm to search the feasible task trajectory. Through the normalized FTWLCC and the improved A* algorithm, the reachability and load carrying capacity of the degraded space manipulator are evaluated, and the reachable and capable trajectory can be obtained. The establishment of FTWLCC provides a novel idea that combines mathematical statistics with failure tolerance performance to illustrate the distribution of load carrying capacity in three-dimensional space, so multiple performance indices can be analyzed simultaneously and visually. And the full consideration of all possible failure situations and motion states makes FTWLCC and improved A* algorithm be universal and effective enough to be appropriate for random joint failure and variety of requirement of large load carrying tasks, so they can be extended to other types of manipulators.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.04.052
      Issue No: Vol. 148 (2018)
  • Trajectory design for the System of Observation of Daytime Asteroids
    • Authors: Irina D. Kovalenko; Boris M. Shustov; Natan A. Eismont
      Pages: 205 - 209
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Irina D. Kovalenko, Boris M. Shustov, Natan A. Eismont
      System of Observation of Daytime Asteroids (SODA) is a space mission project, intended to detect and monitor hazardous asteroids approaching the Earth from the Sun direction, namely from the daytime sky. In particular, the SODA mission aims to detect small celestial objects of size about 10 m, approaching the Earth from directions inaccessible to ground-based and near-Earth space-based telescopes, and to inform beforehand whenever a risk of collision with the Earth occurs. The system uses one or two spacecraft launched into the vicinity of the Lagrangian point L1 of the Sun-Earth system, about 1.5 million km from the Earth. This paper considers main aspects of trajectory design for the SODA project at its initial stage. Selection of an orbit about L1 point, transfer from the Earth and stationkeeping in the vicinity L1 are discussed. A launch scheme making use of a lunar gravity assist is proposed to achieve a desired configuration of the two spacecraft.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.007
      Issue No: Vol. 148 (2018)
  • Numerical investigation of a combined solid fuel scramjet combustor
    • Authors: Ming Hu; Zhijun Wei; Shiqi Ding; Ningfei Wang
      Pages: 210 - 219
      Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148
      Author(s): Ming Hu, Zhijun Wei, Shiqi Ding, Ningfei Wang
      A new scramjet configuration using solid fuel as propellant is proposed, namely, the combined solid fuel scramjet. The combined solid fuel scramjet combustor has been investigated numerically to predict its characteristics. Two-dimensional axisymmetric Reynolds-averaged Navier–Stokes equations and species transport equations are solved numerically. Turbulence closure is achieved using the shear stress transport k-ω model. Three global one-step reaction mechanisms are used in this study. The experimental data in the published literature has been used to validate the accuracy of numerical model. The results of the numerical analysis show that secondary combustion occurs in the supersonic combustor. At the combustor outlet, the total pressure loss is about 0.65 and the combustion efficiency is about 48%. A subsonic recirculation zone is formed near the wall between the air inlet and the fuel-rich gas inlet, which is beneficial to mixing and flame holding. A normal shock wave is generated at the end of the expansion zone after the fuel-rich gas is injected into the combustor, and this is due to the strong pressure downstream induced by secondary combustion.

      PubDate: 2018-05-28T03:34:00Z
      DOI: 10.1016/j.actaastro.2018.05.021
      Issue No: Vol. 148 (2018)
  • Benchmarking inscribed matter probes
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Michael Hippke, Paul Leyland, John G. Learned
      We have explored the optimal frequency of interstellar photon communications and benchmarked other particles as information carriers in previous papers of this series. We now compare the latency and bandwidth of sending probes with inscribed matter. Durability requirements such as shields against dust and radiation, as well as data duplication, add negligible weight overhead at velocities v < 0.2 c. Probes may arrive in full, while most of a photon beam is lost to diffraction. Probes can be more energy efficient per bit, and can have higher bandwidth, compared to classical communication, unless a photon receiver is placed in a stellar gravitational lens. The probe's advantage dominates by order of magnitude for long distances (kpc) and low velocities ( < 0.1 c ) at the cost of higher latency.

      PubDate: 2018-06-21T09:56:36Z
  • Historical-orbital-data-based method for monitoring the operational status
           of satellites in low Earth orbit
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Tao Li, Lei Chen
      A method is developed for monitoring the operational status of satellites in low Earth orbit (LEO) based on their historical two-line element (TLE) data. In this method, whether the satellite still has the maneuverability to maintain the orbital altitude is used as the criteria for judging the operational status, the whole judgment process includes two steps. The first step is to design a specialized algorithm to detect orbit maintenance maneuvers from the satellite's TLE time-history. The algorithm uses abnormal data segments of the TLE derived semi-major axis time series to identify the orbit maintenance maneuver, and various measures are taken to eliminate the noise interference and to ensure the detection accuracy. The second step is to use the detected maneuvering history to determine the current operational status of the satellite. In this step, the statistical technique is used to get the temporal regularity of the satellite to implement orbit maintenance maneuvers and the allowable range of the natural variation of the semi-major axis, so then the criteria for determining the satellite operational status is developed. Analysis of typical LEO satellites indicates that this method can accurately determine the current operational status of the satellite and provide an approximate estimation interval of the satellite retiring time, which is of practical value.

      PubDate: 2018-06-21T09:56:36Z
  • Uncertain surface accuracy evaluation based on non-probabilistic approach
           for large spacecraft
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Chen Yang, Xinbin Hou, Li Wang
      The influence of the surface shape state upon the performance and function of large spacecraft should be considered in design and analyzed in the extreme space environment. Therefore, in this paper, considering the measurement uncertainties and errors exist in large high-precision spacecraft, an interval surface accuracy evaluation method is proposed based on a non-probabilistic approach. To overcome the limitations of insufficient statistical quantification of uncertain parameters, this paper treats uncertainties as non-probabilistic intervals. The conventional root mean square index is extended to uncertain interval numbers, which can be used to evaluate the surface accuracy with the measurement uncertainties and errors. Moreover, to improve the interval expansion problem, subinterval technology is applied to the uncertainty propagation process for surface accuracy evaluation. As long as the bounds of the uncertainties and errors are known, the interval bound for uncertain surface accuracy can be estimated conveniently by interval analysis. Finally, three engineering examples are separately proposed to evaluate the interval surface accuracy thereby validating the effectiveness and veracity of the proposed method. The result obtained in this paper can be regarded as an interval estimator, offering more detailed evaluations and suggestions for large spacecraft design and analysis than deterministic methods.

      PubDate: 2018-06-21T09:56:36Z
  • Experimental study of near-blowoff characteristics in a cavity-based
           supersonic combustor
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Xiliang Song, Hongbo Wang, Mingbo Sun, Yanxiang Zhang
      Lean blowoff characteristics of an ethylene-fueled model scramjet combustor with cavity flameholder are investigated under the inflow conditions of Ma = 2.52 and T0 = 1600 K. It is observed that, lean blowoff limits increase with increasing injection distance and which for the single-orifice cases are found to be higher than those for the multiple-orifice cases. For the multiple-orifice cases studied, once the flame is ignited, it can always be stabilized by the cavity as long as the fuel supply is constant. For the single-orifice cases, however, the flame can be extinguished intermittently even if the fuel is served continuously. That is, the lean flames are more stable for the multiple-orifice cases. Near-blowoff dynamics are then analyzed for the less unstable single-orifice cases. When the lean blowoff limits are approached, the cavity flames become less and less stable and may be partially extinguished. Nevertheless, the residual flame within the cavity may reignite the combustible mixture outside the cavity and the entire flame may restabilize. When the equivalence ratio is further decreased, ultimate blowoff takes place and is found to occur in multiple steps - the shear-layer flame becomes weaker, the flame is partially extinguished near the trailing edge, the flame shrinks into the latter part of the cavity, the flame moves towards the cavity front wall and is subsequently extinguished completely.

      PubDate: 2018-06-18T13:43:35Z
  • Benchmarking information carriers
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Michael Hippke
      The search for extraterrestrial communication has mainly focused on microwave photons since the 1950s. We compare other high speed information carriers to photons, such as electrons, protons, and neutrinos, gravitational waves, inscribed matter, and artificial megastructures such as occulters. The performance card includes the speed of exchange, information per energy and machine sizes, lensing performance, cost, and complexity. In fast point-to-point communications, photons are superior to other carriers by orders of magnitude. Sending probes with inscribed matter requires less energy, but has higher latency. For isotropic beacons with low data rates, our current technological level is insufficient to determine the best choice. We discuss cases where our initial assumptions do not apply, and describe the required properties of hypothetical particles to win over photons.

      PubDate: 2018-06-18T13:43:35Z
  • Analysis of lithium-combustion power systems for extreme environment
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Christopher J. Greer, Michael V. Paul, Alexander S. Rattner
      The longest duration mission on the Venus surface was Venera 13 at just over 2 h. This time constraint was due to limited battery power life and craft thermal management challenges. A lithium combustion based power system has been proposed to increase landed mission durations for Venus and other extreme environment targets. This paper presents a new detailed thermodynamic and heat transfer model of a conceptual lithium combustion power system. Findings are applied to specify engineering requirements for potential missions. Results indicate that a lithium combustion power system using the in-situ carbon dioxide atmosphere as an oxidizer could power a Venus lander for up five days (24 h, Earth day) with 185 kg of fuel, delivering 14 kWth thermal energy continuously. Even greater durations are possible if lower power missions are considered. The potential performances of a Li-CO2 powered Stirling engine and sulfur-sodium batteries were compared. It was found that sulfur-sodium batteries would require about 1.75–2.5 times more mass to provide 1 kW of power output for mission durations of five to ten days, respectively. A lithium combustion power system with a sulfur-hexafluoride oxidizer could power a Europa lander at 94W with a Stirling engine for up to twenty days with 43 kg of reactants mass. Lithium-combustion activated Stirling engines and TEG arrays were compared with batteries to meet this power and mission duration requirement. It was found that batteries would require less mass than either lithium-fueled system. However, for mission durations longer than twenty-six days the Stirling engine power system may require less total mass than batteries. Future work will include laboratory-based experimental studies to validate results and improve heat transfer closure models.

      PubDate: 2018-06-18T13:43:35Z
  • Multi-objective integrated robust H∞ control for attitude tracking
           of a flexible spacecraft
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): Shunan Wu, Weimeng Chu, Xue Ma, Gianmarco Radice, Zhigang Wu
      This paper investigates the multi-objective attitude tracking problem of a flexible spacecraft in the presence of disturbances, parameter uncertainties and imprecise collocation of sensors and actuators. An integrated robust H∞ controller, including an output feedback component and a feedforward component, is proposed, and its gains are calculated by solving Linear Matrix Inequalities. The output feedback component stabilizes the integrated control system while the feedforward component can drive the attitude motion to track the desired angles. The system robustness against disturbances, parameter uncertainties and imprecise collocation is addressed by the H∞ approach and convex optimization. Numerical simulations are finally provided to assess the performance of the proposed controller.

      PubDate: 2018-06-18T13:43:35Z
  • Lessons learned in 20 years of application of Systems Concurrent
           Engineering to space products
    • Abstract: Publication date: October 2018
      Source:Acta Astronautica, Volume 151
      Author(s): G. Loureiro, W.F. Panades, A. Silva
      This paper aims to present the lessons learned in 20 years of application of the SCE (Systems Concurrent Engineering) approach that evolved over the last 20 years being applied to the development of more than 200 complex system solutions. SCE is an approach to the integrated development of complex systems that applies the systems engineering process, simultaneously, to the product elements of a system solution as well as for the service elements of the system solution, recursively, at every layer of the system solution breakdown structure. The approach was born as the application of the requirements, functional and physical analysis processes to the simultaneous development of a product, its life cycle processes and their performing organizations, at every layer of the product breakdown structure. The continuous application of the approach up to 2010, showed the need to include a stakeholder analysis step, to acknowledge that the solution was comprised of product and organization elements (processes were, in fact, the functions of products and organizations), that a mission layer should be added at the top of the product breakdown structure and that the notion of circumstances should be added to the traditional notion of scenarios. With the increasing use of the approach for system of systems conception and development such as those involving multi-spacecraft solutions, the mission layer needed to be extended to include other life cycle processes (besides the operations processes) concept of service and system service architecture. This requires the development of a system solution breakdown structure that will guide the development of the overall solution. For multi-spacecraft solutions, for example, it is necessary to conceive and architect testing, launching and decommissioning services as early as operations. Also, going into more detail in the approach, modes can be derived from circumstances, interface states and internal states of the system and not only from circumstances, as initially established in the approach. These lessons to be presented were learned during the development of: 1) the Brazilian Strategic Program for Space Systems (PESE) and; 2) the TIM Project (Telematics International Mission), a satellite formation with contributions from many regions in the world.

      PubDate: 2018-06-12T13:32:13Z
  • IFC - Publication Information
    • Abstract: Publication date: August 2018
      Source:Acta Astronautica, Volume 149

      PubDate: 2018-06-06T03:40:21Z
  • IFC - Publication Information
    • Abstract: Publication date: July 2018
      Source:Acta Astronautica, Volume 148

      PubDate: 2018-05-31T03:35:07Z
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