Aerospace Engineering Commons^™

Perjalanan Telkom Dalam Mengoperasikan Satelit Komunikasi Untuk Melayani Kepulauan Indonesia, Tonda Priyanto

Online Journal of Space Communication

Pada tahun 1976 Indonesia menjadi negara ketiga di dunia yang mengoperasikan Sistem Komunikasi Satelit Domestik dengan menggunakan Satelit GSO, yakni sistem Palapa A. Sistem satelit ini memberikan layanan teleponi dan faksimil antarkota di Indonesia dan juga menjadi infrastruktur utama pendistribusian program televisi. Saat ini, TELKOM sudah mengoperasikan jaringan komunikasi satelit selama 28 tahun. Dalam rentang waktu itu, TELKOM mengalami berbagai penyempurnaan teknologi, peningkatan dalam jasa-jasa nilai-tambah, serta juga perubahan-perubahan dalam regulasi. Saat ini TELKOM mengoperasikan dua satelit, PALAPA B4 dan TELKOM-1 untuk memberikan layanan telephony trunking, yang juga mencakup untuk sistem-sistem seluler, dan berperan sebagai tulang punggung data dan Internet …

Historical Overview: The Journey Of Telkom In Operating Communications Satellites To Serve The Indonesian Archipelago, Tonda Priyanto

Online Journal of Space Communication

n 1976, Indonesia became the 3rd nation in the world operating a Domestic Satellite Communication System using GSO Satellites, the PALAPA A system. This satellite system provided telephony and facsimile services between cities in Indonesia and became the main TV program distribution infrastructure.

TELKOM* has been operating satellite communication networks for almost 30 years, TELKOM has experienced technology improvements, value added service improvements and also changes in regulations. Nowadays, TELKOM operates 2 satellites, PALAPA B4 and TELKOM-1, for telephony trunking for cellular systems and as data and Internet backbone throughout Indonesia. This paper is intended to describe the journey of …

Berani Menghadapi Tantangan Teknologi Satelit: Terobosan Nasional Dan Peran Indonesia Di Forum-Forum Internasional, Arnold Djiwatampu

Online Journal of Space Communication

Untuk menyegarkan ingatan kita, sistem satelit domestik Palapa merupakan terobosan teknologi untuk mencapai daerah-daerah terisolasi dan memicu kegiatan-kegiatan usaha.

INTELSAT mulai membuka cakrawala baru untuk komunikasi satelit internasional yang handal, dan Indonesia telah mengambil keputusan bijak untuk segera turut serta, meskipun dihadang berbagai kesulitan di bidang ekonomi.

Indonesia harus mengambil keputusan-keputusan yang penting pada waktu ITU WARC-ORB '85 dan '87 sejalan dengan kepentingan komunitas dunia dan kepentingan nasionalnya sendiri. Bekerja sama dengan operator-operator Mobile Satellite Service (MSS) lainnya, Indonesia mendapatkan persetujuan pada WRC-95 untuk memperbaiki pita frekuensi MSS yang terfragmentasi, serta tambahan alokasi di WRC-2003.

Indonesia ikut serta pula dalam …

Historical Overview: Planning And Development Of Indonesia's Domestic Communications Satellite System Palapa, Marwah Ibrahim

Online Journal of Space Communication

This paper is taken from the author's dissertation written in 1989, entitled The Application of Communications Satellite in Developing Countries: The Case of Indonesia.

Artikel ini merupakan ringkasan dari disertasi penulis berjudul The Application of Communications Satellite in Developing Countries: The Case of Indonesia yang ditulis pada tahun 1989 untuk meraih gelar doktor di American University, Washington. Secara ringkas artikel ini menggambarkan sejarah awal dari Sistem Sateli Komunikasi Domestik Palala, mencakup dari alasan-alasan perlunya Indonesia memiliki sistem satelit seperti itu serta sejarah ringkas pembelian hingga pelucuran satelit Palapa. Pada saat itu, keputusan untuk memiliki satelit sendiri merupakan keputusan yang berani, …

Historical Overview: Braving The Challenge Of Satellite Technologies: National Breakthroughs And Indonesia's Role In International Forums, Arnold Djiwatampu

Online Journal of Space Communication

At the time INTELSAT made available for the first time reliable international satellite communication in the 1960's, Indonesia made a wise decision to join the Consortium of Satellite-Using Nations, notwithstanding the economic hardships it posed to participate. Later in the 1970's, the launch of Indonesia's Palapa domestic satellite was a breakthrough technology for addressing isolated areas, and triggering business activities.

Indonesia had crucial decisions to make during ITU's WARC-ORB 1985 and 1987 regulatory deliberations in the interest of the global community and its own national interest. In cooperation with other Mobile Satellite Services (MSS) operators, Indonesia obtained an endorsement at …

Issue 8: From The Guest Editor, Sukarno Abdulrachman

Online Journal of Space Communication

Selamat Datang di edisi 8 dari majalah "Online Journal of Space Communication," yang merupakan Terbitan Khusus dengan tema "Peran Satelit dalam Pembangunan Nasional Indonesia."

Pada saat perkembangan teknologi satelit di dunia masih berada pada tahap sangat awal, Indonesia sudah menyadari bahwa penggunaan angkasa luar untuk keperluan damai pada umumnya, dan komunikasi melalui satelit pada khususnya, dapat berdampak sangat positif dan dapat berperan penting dalam pembanguna nasional Indonesia.

Indonesia sebagai negara kepulauan terbesar di dunia, dengan penduduk lebih dari 200 juta manusia yang tersebar tidak merata di antara ribuan pulau, menghadapi tantangan utama yaitu membangun, memelihara serta mengembangkan prasarana yang bermanfaat …

Review: Factors Affecting Composite Laminates Against Lightning Strikes, Aaryan Manoj Nair

Publications and Research

Lightning strike protection (LSP) have recently been a newly developing field particularly with the emergence of graphene thin film integration into carbon fiber composite structures. This technology has a widespread application in airplanes, wind turbines, and other instruments which are susceptible to frequent lightning strikes. Electrical discharge of the instrument in a safe manner is vital for the safety of the passengers (in the case of flights) as well as the integrity of the aircraft structures because of their specific mechanical and structural properties, which are essential for their functioning. The purpose of the study is to fabricate graphene thin …

Modernization Of Scienttific Mathematics Formula In Technology, Iwasan D. Kejawa Ed.D, Prof. Iwasan D. Kejawa Ed.D

Department of Mathematics: Faculty Publications

Abstract
Is it true that we solve problem using techniques in form of formula? Mathematical formulas can be derived through thinking of a problem or situation. Research has shown that we can create formulas by applying theoretical, technical, and applied knowledge. The knowledge derives from brainstorming and actual experience can be represented by formulas. It is intended that this research article is geared by an audience of average knowledge level of solving mathematics and scientific intricacies. This work details an introductory level of simple, at times complex problems in a mathematical epidermis and computability and solvability in a Computer Science. …

Europa Environmental Testing Of Thermal Hardware For The Mapping Imaging Spectrometer For Europa (Mise) Instrument, Ian M. Mckinley, Jose I. Rodriguez, Mason Mok, Kristen S. Maynard, Curtis Bingham, Andrew Ostler, Patrick Strong

Space Dynamics Laboratory Publications

The Europa Clipper spacecraft, scheduled for launch in June 2022, hosts a suite of instruments including the Mapping Imaging Spectrometer for Europa (MISE). MISE is a high-optical through-put push-broom infrared imaging spectrometer that can collect measurements within Europa’s challenging radiation environment. It is externally mounted to the spacecraft and as a result is exposed to high radiation levels and cold temperatures. The instrument consists of a scan mirror assembly, an optical bench including a Dyson spectrometer and a telescope, and a structure that supports a cryocooler and a radiator. The cryocooler is used to actively cool the focal plane array …

Design And Flight-Path Simulation Of A Dynamic-Soaring Uav, Gladston Joseph

Doctoral Dissertations and Master's Theses

We address the development of a dynamic-soaring capable unmanned aerial vehicle (UAV) optimized for long-duration flight with no on-board power consumption. The UAV’s aerodynamic properties are captured with the integration of variable fidelity aerodynamic analyses. In addition to this, a 6 degree-of-freedom flight simulation environment is designed to include the effects of atmospheric wind conditions. A simple flight control system aids in the development of the dynamic soaring maneuver. A modular design paradigm is adopted for the aircraft dynamics model, which makes it conducive to use the same environment to simulate other aircraft models. Multiple wind-shear models are synthesized to …

Modeling Of A Hybrid-Electric System And Design Of Control Laws For Hybrid-Electric Urban Air Mobility Power Plants, Sohail Bin Salam Lahaji

Doctoral Dissertations and Master's Theses

Advanced Air Mobility (AAM) is an emerging market and technology in the aerospace industry. These systems are being developed to overcome traffic congestion. The current designs make use of Distributed Electric Propulsion (DEP): either fully electric or hybrid electric. The hybrid engine system consists of two power sources: prime movers, such as turbine engines, and batteries. The hybrid systems offer higher range and endurance compared with the existing fully electric systems. Hybrid-electric power generation systems for AAM have different mission requirements when compared to systems used in automobiles. Therefore, there is a particular need to model hybrid-electric systems and the …

Fault Tolerant Deep Reinforcement Learning For Aerospace Applications, Christoph Elias Aoun

Doctoral Dissertations and Master's Theses

With the growing use of Unmanned Aerial Systems, a new need has risen for intelligent algorithms that not only stabilize or control the system, but rather would also include various factors such as optimality, robustness, adaptability, tracking, decision making, and many more. In this thesis, a deep-learning-based control system is designed with fault-tolerant and disturbance rejection capabilities and applied to a high-order nonlinear dynamic system. The approach uses a Reinforcement Learning architecture that combines concepts from optimal control, robust control, and game theory to create an optimally adaptive control for disturbance rejection. Additionally, a cascaded Observer-based Kalman Filter is formulated …

On The Local Heat Transfer Behavior Of Supercritical Carbon Dioxide, Neil Sullivan

Doctoral Dissertations and Master's Theses

A detailed study of the local heat transfer behavior of supercritical carbon dioxide (sCO2) is performed. Flows relevant to heat transfer devices, such as sCO2 heaters, recuperators, and internally cooled turbine blades are studied, with particular attention paid to data reduction methodology, and the use of appropriate reference quantities, nondimensionalizations, and correlations. Additionally, a semi-intrusive temperature measurement technique capable of obtaining highly spatially resolved temperature distributions is adapted for use in the challenging conditions of supercritical (SC) flow. SC fluids have proven difficult to study both experimentally and numerically due to dramatically changing thermodynamic and transport properties near the critical …

Scheduling Allocation And Inventory Replenishment Problems Under Uncertainty: Applications In Managing Electric Vehicle And Drone Battery Swap Stations, Amin Asadi

Graduate Theses and Dissertations

In this dissertation, motivated by electric vehicle (EV) and drone application growth, we propose novel optimization problems and solution techniques for managing the operations at EV and drone battery swap stations. In Chapter 2, we introduce a novel class of stochastic scheduling allocation and inventory replenishment problems (SAIRP), which determines the recharging, discharging, and replacement decisions at a swap station over time to maximize the expected total profit. We use Markov Decision Process (MDP) to model SAIRPs facing uncertain demands, varying costs, and battery degradation. Considering battery degradation is crucial as it relaxes the assumption that charging/discharging batteries do not …

High-Order Positivity-Preserving L2-Stable Spectral Collocation Schemes For The 3-D Compressible Navier-Stokes Equations, Johnathon Keith Upperman

Mathematics & Statistics Theses & Dissertations

High-order entropy stable schemes are a popular method used in simulations with the compressible Euler and Navier-Stokes equations. The strength of these methods is that they formally satisfy a discrete entropy inequality which can be used to guarantee L₂ stability of the numerical solution. However, a fundamental assumption that is explicitly or implicitly used in all entropy stability proofs available in the literature for the compressible Euler and Navier-Stokes equations is that the thermodynamic variables (e.g., density and temperature) are strictly positive in the entire space{time domain considered. Without this assumption, any entropy stability proof for a numerical scheme …

Scaling Flight Test Data Between A Scaled Aircraft And A Cessna 172 For Use In Trajectory Energy Model Validation, Cody William Nettleton

Theses and Dissertations

Currently in the general aviation sector, a new type of aircraft is rising to prominence. It is known as Urban Air Mobility (UAM) and takes many shapes and sizes. The goal of UAM is to produce aircraft that can be used to travel into and out of the city in an efficient manner through the sky. This may cut down on many people’s commutes and lower the amount of ground traffic in cities. One core component of UAM research is to determine the fuel consumption during phases of flight such as conventional takeoff and landing, as well as cruise travel …

Reduced Sample Minimum Strength Estimates For Novel Material Systems: Effects On Confidence And Structural Risk, Andrew Carl Ollikainen

Theses and Dissertations

There are ongoing efforts to standardize the materials, methods and process controls used in additive manufacturing. To support the broader use of additive manufacturing (AM) in the aerospace industry, the statistics working group of the Composite Materials Handbook (CMH-17) is evaluating whether its current methods of calculating minimum strength values are suitable for these new materials. The work presented in this dissertation investigates methods for determining minimum strength estimates in a way that will benefit application of AM materials in engineering practice. The greatest challenge in conducting such an assessment is accounting for the many variables in material, processing, and …

The Importance Of Strategic Communication For Building Employee Resource Groups In Aviation, Lynnette Darnell

Doctoral Dissertations and Projects

In this qualitative case study, the research explores the importance of strategic communication for building employee resource groups in aviation, specifically at a regional airline. To expand and develop knowledge regarding employee resource groups, the researcher looks at a widely distributed workforce to understand how the lack of strategically planned communication can impact employee resource group development and employee engagement. The data were collected through semi-structured interviews and a focus group of the employee resource group members, which provided insight on their experience engaging with the employee resource groups, preferred communication methods and tools, and their perception of leadership involvement. …

Monte-Carlo-Based Analysis Of Traffic Flow For Urban Air Mobility Vehicles, Sara Ghayouraneh

Graduate Theses and Dissertations

The research conducted in this dissertation is focused on developing a simulation tool that can predict the traffic flow patterns of the Urban Air Mobility vehicles to alleviate some of the challenges related to their traffic management. First, an introduction to the concept of Urban Air Mobility is given, the usage of Automatic Dependent Surveillance-Broadcast systems for Urban Air Mobility vehicles is suggested and dynamic addressing concept is introduced as an answer to a part of air traffic management and address scarcity challenge for Urban air Mobility vehicles. Next, in order to simulate the traffic flow patterns of the Urban …

Analysis Of A Non-Equilibrium Vortex Pair As Aircraft Trailing Vortices, Manuel Ayala

Mechanical & Aerospace Engineering Theses & Dissertations

Shortly after the roll-up evolution of the vortex sheet behind the wings of an aircraft, a coherent counter-rotating vortex pair emerges. Presence of this vortex pair in the downstream of an aircraft, creates unsafe conditions for other aircraft, especially near airport runways. Fundamental knowledge of the physics that govern the formation, duration and dissipation of aircraft wake vortices is desirable in order to improve aircraft operational safety. This study uses non-equilibrium pressure theory to develop an accurate model describing the physical behavior of the vortex pair created by an aircraft in the early to mid-field vortex regime. An isolated aircraft …

The Effect Of Through Thickness Reinforcement On Debonding Behavior Of Skin/Stringer Configuration, Yogaraja Sridhar

Mechanical & Aerospace Engineering Theses & Dissertations

Investigation of this study is to the determine the crack propagation and disbonding in the bonded region of the skin and stringer specimen. An adhesive layer has been used to bond the skin and stringer by using a heat press operation. After the bonding, a drilling method has been adopted to install the through thickness reinforcement in the specimen. The key role of the through thickness reinforcement is to increase the stiffness and strength of the panels and to prevent the crack propagation or disbonding of the panels. The reinforcement was installed in pure (Pristine) samples and in defect samples …

A Digital One Degree Of Freedom Model Of An Electromagnetic Position Sensor, Michelle Elizabeth Weinmann

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this project was to improve an existing system currently in use by NASA Langley Research Center (LaRC). The 6-inch Magnetic Suspension and Balance System (MSBS) built at MIT is operational with control in three degrees of freedom, with two additional degrees of freedom exhibiting passive stability. The means for measuring model displacement within the magnetic environment is an Electromagnetic Position Sensor (EPS), consisting of excitation coils at 20 kHz and multiple sets of pickup coils. The pickup coil voltages are proportional to model displacement in each degree of freedom. However, the EPS electronic signal processing system is …

Development And Applications Of Adjoint-Based Aerodynamic And Aeroacoustic Multidisciplinary Optimization For Rotorcraft, Ramiz Omur Icke

Mechanical & Aerospace Engineering Theses & Dissertations

Urban Air Mobility (UAM) is one of the most popular proposed solutions for alleviating traffic problems in populated areas. In this context, the proposed types of vehicles mainly consist of rotors and propellers powered by electric motors. However, those rotary-wing components can contribute excessively to noise generation. Therefore, a significant noise concern emerges due to urban air vehicles in or around residential areas. Reducing noise emitted by air vehicles is critically important to improve public acceptance of such vehicles for operations in densely populated areas.

Two main objectives of the present dissertation are: (1) to expand the multidisciplinary optimization to …

Additively Manufactured Dielectric Elastomer Actuators: Development And Performance Enhancement, Stanislav Sikulskyi

Doctoral Dissertations and Master's Theses

The recently emerging and actively growing areas of soft robotics and morphing structures promise endless opportunities in a wide range of engineering fields, including biomedical, industrial, and aerospace. Soft actuators and sensors are essential components of any soft robot or morphing structure. Among the utilized materials, dielectric elastomers (DEs) are intrinsically compliant, high energy density polymers with fast and reversible electromechanical response. Additionally, the electrically driven work principle allows DEs to be distributed in a desired fashion and function locally with minimum interference. Thus, a great effort is being made towards utilizing additive manufacturing (AM) technologies to fully realize the …

Issue 7: Contributors, David Hartshorn, Martin Jarrold

Online Journal of Space Communication

List of Issue 7 Contributors.

Future Solutions: Access To Ict: A Tale Of Three Briefings, David Hartshorn

Online Journal of Space Communication

If your inbox is anything like mine, then you already know that the publication of satellite communications reports has become an industry unto itself. But that's not to say that it's always an end unto itself. On the contrary.

Future Solutions: Universal Access, David Hartshorn

Online Journal of Space Communication

Today, the nations of the world have an immediate opportunity to advance essential telecommunication policy objectives through harmonisation of regulations governing the use of fixed satellite-based network solutions.

Regulatory Reform: Strengthening Access To Information & Communications Technologies: Guidelines To Facilitate Policy & Regulation For Satellite Services, Global Vsat Forum

Online Journal of Space Communication

This document was prepared by GVF, an association of organisations engaged in the delivery of advanced broadband and narrowband satellite services to consumers, and commercial and government enterprises worldwide.

Regulatory Reform: In The Land Of The 'Coffeenet', Martin Jarrold

Online Journal of Space Communication

Sitting down to write this article at a desk some 30 miles south of central London, and less than one degree west of the Greenwich meridian, I became immediately more conscious than usual of geography. The frequently interwoven use of such western-centric cartographic labels as Middle East, and Far East, with the geographically more precise terms of Western or Central Asia, and East and South-East Asia, sometimes causes us to confuse the actual proximity of Europe's, much larger, near-neighbour.

Regulatory Reform: Asia's Great Step Forward, David Hartshorn

Online Journal of Space Communication

This paper was presented at Connect-World Asia Pacific, June 2002.

Forget about a great leap forward. All that's needed to facilitate communications in Asia are a few small steps. Indeed, today all nations of the world have an immediate opportunity to advance essential telecommunication policy objectives through harmonisation of regulations governing the use of telecommunications solutions.