1. BRIDGING THE GAP IN NIGERIA’S EARTH OBSERVATION SATELLITES – A CALL FOR SYNTHETIC APERTURE RADAR
Onwuama Chukwuweike Ihunanya
Centre for Satellite Technology Development, NASRDA, Abuja, Nigeria Onwuama.chukwuweike@cstd.nasrda.gov.ng
Abstract:- Over the years, optical remote sensing instruments have been applied in various areas of Earth Observation (EO) such as disaster monitoring, agriculture, forestry, desertification, land-cover mapping, urban planning, surveillance, defense and security etc. These areas of application have been implemented in Nigeria by the National Space Research and Development Agency (NASRDA), through the launch of NigeriaSat-1, NigeriaSat-X and NigeriaSat-2 satellites which are equipped with optical imaging payloads ranging from Medium to Very High Resolution Imagers. However, due to the peculiar climatic condition of Nigeria, these EO satellites find it difficult to deliver clear sky images all through the year for all parts of the country especially in the Southern region of the country. In order to combat the prevailing challenge imposed by the optical imagers which are usually affected by cloud cover and limited to day light imaging, a Synthetic Aperture Radar (SAR) satellite is hereby presented as an immediate solution.
SAR system utilizes the microwave region of the Electromagnetic (EM) spectrum and is capable of providing its own illumination that can penetrate clouds, thereby through barriers of vision impairment and thus provides observations over night-time activities. These capabilities make SAR systems complement imaging opportunities over cloudy regions especially the Southern part of the Nigeria. This paper briefly reviews the ways of bridging the gap impose by Nigeria’s current EO systems through the implementation of a cost effective SAR satellite.
Keywords: Earth Observation, Synthetic Aperture Radar, Disaster monitoring, Imaging payload.
2. DESIGN IMPLEMENTATION OF AN RF POWER AMPLIFIER FOR SATELLITE COMMUNICATION SYSTEMS.
EDET DAVID*Centre for Satellite Technology Development (NASRDA), Abuja
Landmark University, Omu-Aran, Kwara State, Kokoette.edet @lmu.edu.ng
ABSTRACT:
This paper focus on the design of RF power amplifiers for satellite communication systems. The rapid growth in the use of power amplifiers for satellite communication is been nothing short of phenomenal. One of the major part of a high frequency communication system is the power amplifiers which amplifiers signals more than 3GHz, into a frequency in the order of millions of cycles, the design of a radio frequency power amplifiers is the most obvious solution to overcoming the battery lifetime limitation in the satellite communication system, this paper focus on the design of a radio frequency amplifier with a technique to improve the drain efficiency of the class-F amplifier. This technique uses two passive networks; one of them is in series with the shunt capacitor Cs and the order in series with the MOSFET transistor’s source terminal. This technique shows improvement in the drain efficiency, which increases from 62% to 90%, this result to the demand for compact, low cost, and low power RF amplifiers. Thus, the design consideration was implemented, recorded, tested and met design specification.
Keywords: RF Amplifiers, Satellite System, Drain Efficiency, Power MOSFETs
3. SATELLITE OPERATIONS- PRINCIPLES, MANAGEMENT AND AUTOMATION
Sanusi Muhammad, *CSTD-Ground Segment Team, Centre for Satellite Technology Development, Obasanjo Space Centre, Airport Road, Pykassa Junction, Garki Abuja
email: msanusi2009@yahoo.co.uk
ABSTRACT
Launching satellites and maintaining a mission while in orbit is a procedural and expensive activity. It is therefore imperative satellite operations are designed to suit mission requirements so that operational activities are planned and managed properly. The earth station design and mission control planning are con-currently conducted with satellite payload and platform design and development. This strategy will ensure adequate testing of both satellite and ground facilities prior launching into the desired orbit. In this paper, the modern satellite ground operations principles are reviewed and discussed. To sustain a successful mission ground facilities including the hardware and software components maintenance is a key requirement hence critical issues involved are discussed in this paper. Also required human resources and responsibilities that are satisfactory and suitable are discussed. In contemporary missions and operations, activities are automated for effective mission cost and safer mission control and operations. In view of that automated principles are reviewed and an automated keplarian elements fetching software is developed and described. Also a re-configurable and flexible control algorithm for mission tasks operation is proposed to provide improvement in mission planning and control systems(MPS).
KeyWords: Satellite Operations, Management, Automation, maintenance.
4. SOCIO-ECONOMIC BENEFITS OF MICROGRAVITY RESEARCH
*a Esther Moradeke Afolayan, bFunmilola Adebisi Oluwafemi, cExcel Jeff-Agboola, dTimilehin Oluwasegun
*a Space
Life Science Unit, National Space Research and Development Agency, Airport
Road, Abuja, Nigeria.
(E-mail: morayoesther@gmail.com
+2348160943967)
b Space Life Science Unit,
National Space Research and Development Agency, Airport Road, Abuja, Nigeria.
(E-mail: oluwafemifunmilola@gmail.com)
cd Joseph
Ayo Babalola University, Nigeria.
(E-mail: yjeffagboola@yahoo.com,
tibexx31@gmail.com)
Abstract
Microgravity literally means little gravity;(Microgravity: Earth and Space An Educator’s Guide with Activities in Technology, Science, and Mathematics Education) it is a state of weightlessness. Microgravity research are those research conducted in low gravity environment. These low gravity environment can be achieved in a number of ways including parabolic aircraft flights, sounding rockets, drop towers, clinostat, etc. Gravity dominates everything on earth, from the way life has developed to the way materials interact.(Microgravity: Earth and Space An Educator’s Guide with Activities in Technology, Science, and Mathematics Education) The reduction of gravity cause significant changes in the chosen sample which could be cells, plants, micro-organisms and small samples from material sciences. The changes that occur as a result of the effect of microgravity have led to discoveries that have been found to be of socio-economic benefits. Socio-economic benefits involve benefits in wealth, health, economic, environment etc. Sustainable development in an economy includes economic growth, environmental protection and social equality. Space technology applications such as in microgravity stimulate economic growth and improve the quality of life of people; thereby beneficial to mankind. Overall products manufactured in microgravity environments have key properties usually surpassing the best terrestrial counterparts. Commercially, these products have attractive features that facilitate marketing.
Ioana Cozmuta, Lynn D Harper, Daniel J Rasky, Robert B Pittman, Alexander C MacDonald (2014). Microgravity for economic growth and public benefit.
. More than 818 patents have been granted from 1981 as related to the subject of microgravity, the use of patents as an indicator of value creation signifies economic potential. This review will consider the various benefits of microgravity research in life-sciences such as in biotechnology, microbiology, pharmacy, medicine etc.
Keywords: Microgravity Research, Socio-Economic, Life-Sciences
5. IMPACT OF CLIMATE CHANGE ON THE DESIGN PARAMETERS OF HEATING, VENTILATION AND AIR CONDITIONING SYSTEMS FOR SPACECRAFT.
*Idris Ibrahim Ozigis and Shade Ibidunni Ishola
Department of Mechanical Engineering, University of Abuja, FCT.
*Idris.ozigi@gmail.com; 08062984934
omolehinmi@yahoo.com;08055363892
Abstract
The study presents impact of climate change on the design parameters of Heating, Ventilation and Air Conditioning (HVAC) systems for spacecraft. Firstly, the climate parameters include outdoor dry-bulb temperature, coincident wet-bulb temperature and relative humidity. The data for these parameters for Ikeja, Lagos, Nigeria, for a period of fifteen years (1995-2009), were obtained from Nigerian Meteorological Agency (NIMET), Oshodi, Lagos. The climate design parameters for Atlanta, GA, USA, were obtained from literature for a period of 1982 to 2006, on one hand and in another hand, design climatic information for Niamey, Niger, were obtained from literature. Ikeja, Lagos, Nigeria, Atlanta, GA, USA and Niamey, Niger, were hypothetically chosen and to compare results of the climate parameters due to their heavy traffic of airplanes with large weather data generation. Secondly, the work involves use of statistics and Microsoft excel software for evaluation of variation trend of the climate parameters for departure city, which is very important in determining thermal comfort of payload in spacecrafts on ascent. The Lagos dry-bulb temperature average results obtained were 33.81, 32.98, 32.3, 22.1, 21.19, 20.43, 23.84 and 31.65 at 0.4%, 1.0%, 2.0%, 97.5%, 99.0%, 99.6%, median of extreme lows and median of extreme highs, respectively. The Lagos relative humidity average results were 116.3, 112.65, 109.14, 99.83 and 49.42 at 0.4%, 1% and 2.0% occurrence as well as median of extreme highs and median of extreme lows, respectively. Ikeja, Lagos, had mean coincident dry bulb temperature of 33.8°C and 32.98°C at 0.4% and 1% percentile respectively. The heat dry bulb temperature for Ikeja, Lagos, was determined to range from 20.43°C to 22.1°C from January to December, in the period of 1995-2009, at 97.5% 99% and 99.6% percentile respectively.
6. SATELLITE OPERATIONS- PRINCIPLES, MANAGEMENT AND AUTOMATION
Sanusi Muhammad, *CSTD-Ground Segment Team, Centre for Satellite Technology Development, Obasanjo Space Centre, Airport Road, Pykassa Junction, Garki Abuja
email: msanusi2009@yahoo.co.uk
Abstract
Launching satellites and maintaining a mission while in orbit is a procedural and expensive activity. It is therefore imperative satellite operations are designed to suit mission requirements so that operational activities are planned and managed properly. The earth station design and mission control planning are con-currently conducted with satellite payload and platform design and development. This strategy will ensure adequate testing of both satellite and ground facilities prior launching into the desired orbit. In this paper, the modern satellite ground operations principles are reviewed and discussed. To sustain a successful mission ground facilities including the hardware and software components maintenance is a key requirement hence critical issues involved are discussed in this paper. Also required human resources and responsibilities that are satisfactory and suitable are discussed. In contemporary missions and operations, activities are automated for effective mission cost and safer mission control and operations. In view of that automated principles are reviewed and an automated keplarian elements fetching software is developed and described. Also a re-configurable and flexible control algorithm for mission tasks operation is proposed to provide improvement in mission planning and control systems(MPS).
KeyWords: Satellite Operations, Management, Automation, Maintenance
7. DYNAMIC MECHANICAL ANALYSIS OF UKAM FIBRE REINFORCED POLYESTER COMPOSITES
Okpanachi, G.E, Centre for Satellite Technology Development, National Space, Abuja. Okpanachi1976@gmail.com, 08039718721
ABSTRACT
Natural fibers show potential to replace glass fibers in thermoset and thermoplastic composites. Ukam is a bast-type fiber with high specific strength and great potential to compete with glass fibers. In this research Ukam/polyester composites were analyzed using Dynamic Mechanical Analysis (DMA). A three-point bend apparatus was used in the DMA testing. The samples were tested at 2 hertz, 5 hertz and 10 hertz at a displacement of 10 μm, and at room temperature. The fiber volume content of the Ukam was varied from 5%, 10%,15%,20% and 25%. Ten samples of each fiber volume fraction were manufactured and tested. The flexural storage modulus, the flexural loss modulus, and the loss factor were reported. Generally, as the fiber volume fraction of Ukam increased, the flexural storage and flexural loss modulus increased. The loss factor remained relatively constant with increasing fiber volume fraction.
Keywords: Ukam, polyester resin, composite, storage modulus, loss modulus
8. SATELLITE COMMUNICATION LINK EVALUATION VIA VSAT NETWORK
Orisekeh, Kingsley I. and Ogbuokebe K.C. Centre for Satellite Technology Development
National Space Research and Development Agency, Abuja, Email: kingsleyorisekeh@yahoo.com/08037786223
Abstract
VSAT stands for very small aperture terminal. It has become a big family of the global satellite communication infrastructure. Its usefulness in today’s businesses cannot be over-emphasized as it provides data transmission links connecting various business sites to a central facility. The first earth station antennas used in commercial satellite communications were very large and expensive, typical aperture diameter of 30m operating in C band (6/4 GHz). This was not easily affordable, hence, the need for VSAT. Today, most VSAT systems operate in ku-band with earth station antenna diameters of 1m and transmitter power of 1 to 2W. The earth stations are usually organized in a star network in which the earth stations connect to a central hub station via a Geostationary Earth Orbit (GEO) satellite. Data rates on the links are from a few thousand bits per second depending on the traffic requirements. This work aimed to address Satellite Communication link design, how to utilize parameters and iteratively improve link design (link budget) to meet specifications vis-à-vis important parameters to be considered in designing and trade-off: Link margins, Quality of service, Service availability, Cost, Antenna size, Access schemes-SCPC-FDMA & TDM, Forward Error Correction (FEC) and Data rate.
Keywords- VSAT, Link Budget, Antenna, FDMA, TDM, FEC, Data rate, C-bands, Ku-bands, GEO Satellite.
9. SATELLITE COMMUNICATION LINK EVALUATION VIA VSAT NETWORK
Orisekeh, Kingsley I. Centre for Satellite Technology Development National Space Research and Development Agency, Abuja Email: kingsleyorisekeh@yahoo.com/08037786223
ABSTRACT
VSAT stands for very small aperture terminal. It has become a big family of the global satellite communications infrastructure. Its usefulness in today’s businesses cannot be over-emphasised as it provides data transmission links connecting various business sites to a central facility. The first earth station antennas used in commercial satellite communications were very large and expensive, typical aperture diameter of 30m operating in C band (6/4 GHz). This was not easily affordable, hence, the need for VSAT. Today, most VSAT systems operate in ku-band with earth station antenna diameters of 1m and transmitter power of 1 to 2W. The earth stations are usually organized in a star network in which the earth stations connect to a central hub station via a Geostationary Earth Orbit (GEO) satellite. Data rates on the links are from a few thousand bits per second depending on the traffic requirements.
This work aimed to address Satellite Communication link design, how to utilize parameters and iteratively improve link design (link budget) to meet specifications vis-à-vis important parameters to be considered in designing and trade-off: Link margins, Quality of service, Service availability, Cost, Antenna size, Access schemes-SCPC-FDMA & TDM, Forward Error Correction (FEC) and Data rate.
Keywords- VSAT, Link Budget, Antenna, FDMA, TDM, FEC, Data rate, C-bands, Ku-bands, GEO Satellite.