Satellite Technology

SATMED: Legal Aspects of the Physical Layer of Satellite-Telemedicine

by Stephen Rooke

Significant disparities exist between the availability of physicians and health care specialists in urban and rural... more Significant disparities exist between the availability of physicians and health care specialists in urban and rural areas, particularly in developing countries. For example, the concentration of medical specialists in Nairobi, Kenya, is 147 times higher than in Kilifi, a relatively large, but rural region. Emerging telemedicine technologies would enable doctors located in urban areas and elsewhere around the globe to serve rural patients. However, the limited availability of telecommunications infrastructure and technology necessary for telemedicine in rural areas inhibits the deployment of such health care applications. For example, in Namtumbo, Tanzania, a region with over 190,000 people, there are no doctors and none of the medical facilities have access to any type of telephone connection. Only twenty percent of Tanzania's health districts are connected by landline telephone.

Satellites' ability to bridge gaps in telecommunications infrastructure gives them a unique capacity to also bridge the urbal-rural health care divide by making telemedicine applications available to rural patients and medical professionals worldwide. Unfortunately, international law provides an expansive grant of national sovereignty over electromagnetic spectrum that supersedes state obligations to provide access to health care. As a result, the physical equipment necessary to provide telemedicine services to rural patients is subject to national regulatory regimes that prevent the widespread and cost-effective availability of life-saving technology.

This paper identifies the body of international law governing satellite-telemedicine including outer space law; conventions governing economic, social and cultural rights and the right to health care; and international telecommunications law including the ITU Constitution, Tampere Convention, and the Global Mobile Personal Communication by Satellite Memorandum of Understanding. It then concludes that an additional international undertaking to eliminate national barriers to entry for satellite-telemedicine technology is necessary.

Modeling And Simulation Of Prolate Dual-Spin Satellite Dynamics In An Inclined Elliptical Orbit: Case Study Of Palapa B2R Satellite

by Agus Budiyono

Symposium on Aerospace Science and Technology, Jakarta, 2005

In response to the interest to re-use Palapa B2R satellite nearing its End of Life (EOL) time, an idea to incline the... more In response to the interest to re-use Palapa B2R satellite nearing its End of Life (EOL) time, an idea to incline the satellite orbit in order to cover a new region has emerged in the recent years. As a prolate dual-spin vehicle, Palapa B2R has to be stabilized against its internal energy dissipation effect. This work is focused on analyzing the dynamics of the reusable satellite in its inclined orbit. The study discusses in particular the stability of the prolate dual-spin satellite under the effect of perturbed field of gravitation due to the inclination of its elliptical orbit. Palapa B2R physical data was substituted into the dual-spin's equation of motion. The coefficient of zonal harmonics J2 was induced into the gravity-gradient moment term that affects the satellite attitude. The satellite's motion and attitude were then simulated in the perturbed gravitational field by J2, with the variation of orbit's eccentricity and inclination. The analysis of the satellite dynamics and its stability was conducted for designing a control system for the vehicle in its new inclined orbit.

A new star (sensor) is born

by Michiel Kruijff

ICSO 2010, Rhodes, Greece, International Conference on Space Optics 4 - 8 October 2010

Johan Leijtens, Willem Vliegenthart, Dimitris Lampridis, Guiseppe Vacanti, Bert Monna, Elbert Bechthum, Koen Hagenaars, Erik van der Heide, Michiel Kruijff, Eddie van Breukelen, Anita LeMair

- This paper reports the prototyping and testing of a compact multihead star sensor for which Delta-Utec developed... more - This paper reports the prototyping and testing of a compact multihead star sensor for which Delta-Utec developed multihead pattern recognition and attitude determination algorithms. A more advanced version of these algorithms for low-sensitivity and reduced FOV camera's has also been developed but is not reported here (Facet Nano project with ISIS), contact M. Kruijff or ISIS for more info.

In the frame of the Dutch Prequalification for ESA programs (PEP), as part of the efforts to design an integrated optical attitude control subsytem (IOPACS), a consortium of TNO and several SME's in the Netherlands have been working on a novel type of startracker called MABS (Multiple Aperture Baffled Startracker). The system comprises a single cast metal housing with four reflective optical telescopes which use only structural internal baffling.
Inherent to the design are a very high stability and excellent co-alignment between the apertures, a significant decrease in system size and low recurring production cost. The concept is a radical change from more common multiple startracker setups. The presentation will concentrate on the validity of the concept, the predicted performance and benefits for space applications, the produced breadboard and measured performances as well as the costing aspects.

Qualification and in-flight demonstration of a European tether deployment system on YES2

by Michiel Kruijff

Acta Astronautica 64 (2009) 882–905
M. Kruijff & E.J. van der Heide

This paper highlights the design, qualification and mission performance of the tether deployer system on the second... more This paper highlights the design, qualification and mission performance of the tether deployer system on the second Young Engineers’ Satellite (YES2), that featured a tethered momentum transfer. The deployer is designed with a broad range of near- term tether applications in mind. The system contains the tether, including features to enhance safety and wound up in controlled manner onto a spool core, optical deployment sensors, a “barberpole” friction brake controlled by a stepper motor and a triple tether cutter system. To initiate the deployment a spring-based ejection system was developed, and to apply accurate momentum transfer a timer and release system is present on the subsatellite side. A small, 6 kg re-entry capsule was developed as subsatellite. On September 25th, 2007, YES2 deployed a 32km tether in orbit and gathered a wealth of data. Confidence is gained from the mission results for use of the deployer in future missions.

The Second Young Engineers’ Satellite: Innovative Technology through Education

by Michiel Kruijff

A not very technical brief description of the YES2 educational design process and mission results.

Fujii, H.A., Kruijff, M., Heide, E.J. van der, Watanabe, T., Ockels, W.J.,
”The Second Young Engineersʹ Satellite: Innovative Technology Through Education,”
2009‐g‐29, 27th International Symposium on Space Technology and Science”, Transactions of Japan Society for Aeronautical and Space Sciences, Space Technology Japan, appearing in JSTS journal Vol. 8, 2010.

This paper introduces an innovative technology through education obtained in the project of the second Young... more This paper introduces an innovative technology through education obtained in the project of the second Young Engineers’ Satellite (YES2) piggybacked on the Foton-M3 microgravity platform.

STRAND-1: USE OF A $500 SMARTPHONE AS THE CENTRAL AVIONICS OF A NANOSATELLITETE

by Christopher Bridges

Shaun Kenyon, Surrey Satellite Technology Ltd. (SSTL), Guildford, Surrey, United Kingdom, s.kenyon@sstl.co.uk

Dr Christopher Bridges, Surrey Space Centre (SSC), University of Surrey, Guildford, Surrey, United Kingdom, c.p.bridges@surrey.ac.uk

Doug Liddle, Bob Dyer, James Parsons, David Feltham, Rupert Taylor, Dale Mellor, Andrew Schofield, Rosie Linehan, Richard Long, Juan Fernandez, Haval Kadhem, Phil Davies, Jonathan Gebbie, Nick Holt (SSTL)

Peter Shaw, Lourens Visagie, Theodoros Theodorou, Dr Vaios Lappas, Dr Craig Underwood (SSC)

STRaND-1 is the first in a series of Surrey Satellite Technology Ltd. (SSTL)-Surrey Space Centre (SSC) collaborative... more STRaND-1 is the first in a series of Surrey Satellite Technology Ltd. (SSTL)-Surrey Space Centre (SSC) collaborative satellites designed for technology path finding for future commercial operations. It is the first time Surrey has entered the CubeSat field and differs from most CubeSats in that it will fly a modern commercial off-the-shelf (COTS) Android smartphone as a payload, along with a suite of advanced technologies developed by the University of Surrey, and a payload from the University of Stellenbosch in South Africa. STRaND-1 is also different in that anyone (not just from the space engineering or space science community) will be eligible to fly their “app" in space, for free. STRaND-1 is currently being manufactured and tested by volunteers in their own free time, and will be ready for an intended launch in the next four months.

This paper outlines the STRaND pathfinder programme philosophy which challenges some conventional space engineering practises, and describes the impact of those changes on the satellite development lifecycle. The paper then briefly describes the intent behind the design of STRaND-1, before presenting details the design of the nanosatellite, focussing of the details of the innovative new technologies; including two different propulsion systems, an 802.11g WiFi experiment, a new VHF/UHF transceiver unit and a miniature 3-axis reaction wheel assembly. The novel processing setup (which includes the smartphone) is discussed in some detail, particularly the potential for outreach via the open source nature of Google's Android operating system. A step-through of the planned concept of operations is provided, which includes a possible rendezvous and inspection objectives, demonstrating equal or improved capability compared to SNAP-1 with a reduced total system mass. Finally, data from the test campaign is presented and compared against other notable CubeSats known for their advanced capabilities. Rendered images of STRaND-1 are shown in Fig. I and are discussed later in the paper.

STRaND: Surrey Training Research and Nanosatellite Demonstrator

by Christopher Bridges

C. P. Bridges, S. Kenyon, C. I. Underwood, M. N. Sweeting

As pico and nanosatellites gain popularity with space educators and institutions, Surrey Space Centre (SSC) and Surrey... more As pico and nanosatellites gain popularity with space educators and institutions, Surrey Space Centre (SSC) and Surrey Satellite Technology Ltd. (SSTL) have collaborated together to build STRaND-1, a nanosatellite based on the 3U-CubeSat standard. The aim of STRaND, or ‘Surrey Training Research and Nanosatellite Demonstration’ programme, is:
• To provide rapid hands-on training experience for academics and less experienced engineers at both centres in designing and building new satellite technologies,
• To challenge the current industry standard development processes and discover new ways of managing developments, and
• To demonstrate novel space technologies or the use of existing but modern terrestrial commercial-off-the-shelf (COTS) technologies in space.

This paper will outline the processes that Surrey, the collective team of SSC and SSTL engineers, went through to design STRaND-1’s mission requirements, and through to the final system design. To cater for a range of new mission requirements, including a new high performance computer, a modern smart-phone with Android operating system, and a novel electric propulsion system. Many custom parts were designed to accommodate a new 3-axis stabilised attitude/orbit control system (AOCS) of micro-wheels, micro-magnetorquer rods, Sun/Earth sensors together with a bespoke payload bay for non-CubeSat standard boards.

DEMONSTRATING VISUAL INSPECTION OF SOLAR SAIL SURFACES

by Christopher Bridges

C.P. Bridges, P. Palmer

Formation flying missions are now at the forefront of new flight qualified space technologies, an example being the... more Formation flying missions are now at the forefront of new flight qualified space technologies, an example being the precise propulsion systems like that flown on the PRISMA mission. One such mission concept designed by Surrey Space Centre is to perform on-orbit visual inspection of a solar sail which aims to demonstrate and validate a new imaging system and a micro chemical propulsion system (μCPS) currently under development by a consortium led by Astrium GmbH. Applications of this new utility can be utilized towards redundant satellite systems, cluster-based sensor networks, rendezvous and docking operations, and visual inspection missions. A model of the solar sail is developed from the classical catenary, whose shape is typically defined by gravitational forces. This method however can be applied to estimate the ‘billowing’ in the solar sail and the resultant net thrust from combined solar radiation pressure and atmospheric drag forces. Furthermore, by investigating the light reflection patterns returned from the solar sail as a function of the sail surface, the accurate estimation of the solar sail shape can be achieved.

As sunlight is reflected from the sail, it is important to understand how the Sun angle affects potential observation points in an orbit. Results for various Sun angles in an inertially-fixed solar sail case-study are presented to find that there are 2 key opportunities for imaging: i) looking at the micro-structure, i.e. shape and attitude, and ii) the macro-structure, i.e. the grazing Sun incidence angles for the sail surface. At these points, the sail shape, attitude, and surface structure can be learnt. A recent example of such a mission is the Japanese Space Agency (JAXA) Ikaros solar sail mission and, together with a deployed satellite, DCAM2, obtained imagery to confirm full deployment of the solar sail. In this imagery, it can be clearly seen when DCAM2 enters the focal point of the sail and the camera is completely saturated with light and little information, other than sail shape, can be made out. Using our simulations and models, a billow of 31.3 cm was estimated for this mission.

This paper proposes the solar sail inspection mission parameters, introduces the new light reflection model and methodology for solar sails, and the formation flying experiment of potential observation points in a 2-1 safety ellipse around the solar sail target using the μCPS.

MIT CASTOR Satellite: design, implementation, and testing of the communication system

by Alessandra Babuscia

Optical Payloads Proposed For High Resolution Earth Imaging Systems

by Waqas Mahmood

NEE-01 PEGASUS: The first Ecuadorian Satellite

by Ronnie Nader

Ultra thin, deployable, multipanel solar arrays for 1U cubesats

by Ronnie Nader

CYCLOPS: REAL TIME VIDEO TRANSMISSION FROM ORBIT ON A 1U CUBESAT MISSION

by Ronnie Nader

CARBON NANOTUBES BASED THERMAL DISTRIBUTION AND TRANSFER BUS SYSTEM FOR 1U CUBESATS

by Ronnie Nader

SEAM/NEMEA: THE SPACE ENVIRONMENT ATTENUATION MANIFOLD SHIELD FOR NANOSATELLITES

by Ronnie Nader

SELF DEPLOYING ANTENNA SYSTEM FOR NANO SATELLITES BASED ON SHAPE MEMORY ALLOYS

by Ronnie Nader

SESCA: SPACE ENVIRONMENT SIMULATION CHAMBER FOR ACCURATE GROUND TESTING OF NANO SATELLITES

by Ronnie Nader

HIGH ENERGY DENSITY MULTI CELL BATTERY ARRAY FOR NANOSATELLITES

by Ronnie Nader

NANO SATELLITE SENSOR ARRAY AND ON-SCREEN VIDEO TELEMETRY SYSTEM

by Ronnie Nader

Blind in a Dark Room? Europe's Space Capacities for Natural Resource Mapping

by Daniel Fiott

Madariaga Paper, Vol. 3, No. 6, (Oct., 2010)

Is the European Union doing all it can to harness the full benefits of space for the purposes of global natural... more Is the European Union doing all it can to harness the full benefits of space for the purposes of global natural resource management? How is the EU presently utilising imagery from space to halt illegal exploitation of resources? What are the technological and political obstacles hindering further progress in this regard? This paper provides a survey of EU space activities and makes recommendations regarding the EU’s role in successfully managing natural resources across the globe from outer space including the suggestion that a European Union Geological Survey be established.