Advanced space system concepts and their orbital support needs (1980 - 2000). Volume 2: Final report

The results are presented of a study which identifies over 100 new and highly capable space systems for the 1980-2000 time period: civilian systems which could bring benefits to large numbers of average citizens in everyday life, much enhance the kinds and levels of public services, increase the economic motivation for industrial investment in space, expand scientific horizons; and, in the military area, systems which could materially alter current concepts of tactical and strategic engagements. The requirements for space transportation, orbital support, and technology for these systems are derived, and those requirements likely to be shared between NASA and the DoD in the time period identified. The high leverage technologies for the time period are identified as very large microwave antennas and optics, high energy power subsystems, high precision and high power lasers, microelectronic circuit complexes and data processors, mosaic solid state sensing devices, and long-life cryogenic refrigerators

Satellite communication and navigation for mobile users

Efforts made to utilize space technology for solving communication and navigation problems faced by mobile users in earth orientated situations are outlined. Applications include transoceanic airline communications, reliable long range ship-shore communications, emergency communications in regions with rough terrain, and military operations

Advanced space system concepts and their orbital support needs (1980 - 2000). Volume 1: Executive summary

The likely system concepts which might be representative of NASA and DoD space programs in the 1980-2000 time period were studied along with the programs' likely needs for major space transportation vehicles, orbital support vehicles, and technology developments which could be shared by the military and civilian space establishments in that time period. Such needs could then be used by NASA as an input in determining the nature of its long-range development plan. The approach used was to develop a list of possible space system concepts (initiatives) in parallel with a list of needs based on consideration of the likely environments and goals of the future. The two lists thus obtained represented what could be done, regardless of need; and what should be done, regardless of capability, respectively. A set of development program plans for space application concepts was then assembled, matching needs against capabilities, and the requirements of the space concepts for support vehicles, transportation, and technology were extracted. The process was pursued in parallel for likely military and civilian programs, and the common support needs thus identified

Concepts for 18/30 GHz satellite communication system study. Executive summary

An examination of a multiplicity of interconnected parameters ranging from specific technology details to total system economic costs for satellite communication systems at the 18/30 GHz transmission bands are presented. It was determined that K sub A band systems can incur a small communications outage during very heavy rainfall periods and that reducing the outage to zero would lead to prohibitive system costs. On the other hand, the economics of scale, ie, one spacecraft accommodating 2.5 GHz of bandwidth coupled with multiple beam frequency reuse, leads to very low costs for those users who can tolerate the 5 to 50 hours per year of downtime. A multiple frequency band satellite network can provide the ultimate optimized match to the consumer performance/economics demands

Compendium of Applications Technology Satellite user experiments

The achievements of the user experiments performed with ATS satellites from 1967 to 1973 are summarized. Included are fixed and mobile point to point communications experiments involving voice, teletype and facsimile transmissions. Particular emphasis is given to the Alaska and Hawaii satellite communications experiments. The use of the ATS satellites for ranging and position fixing of ships and aircraft is also covered. The structure and operating characteristics of the various ATS satellite are briefly described

The STARSYS Global Positioning and Messaging System

STARSYS is a commercially feasible mobile satellite communications system which employs low-Earth orbit (LEO) satellite technology to provide brief two-way messaging and position determination services. STARSYS mobile terminals will be able to send and receive short messages and, through ground computer processing, the system will determine the terminals\u27 location almost anywhere on Earth. These data services will have extensive utility in a number of different applications, such as recovery of stolen property, tracking vehicles and cargoes, remote area positioning and messaging, personal communications, multiple data retrieval, and remote control of systems such as utilities. The market niche for STARSYS-type LEO satellite communications will consist of customers who can effectively employ short, inexpensive data messaging. STARSYS does not, therefore, compete directly with those systems which emphasize voice services. Moreover, with its design emphasis on inexpensive satellites and very low cost terminals, STARSYS will foster the creation of a completely different market of data messaging users, a mass market consisting of millions of commercial users around the globe. Additionally, nearly all of the applications envisioned by STARSYS for its commercial customers have corresponding utility in the government and military marketplaces. The concept of providing satellite messaging and positioning to individual user terminals has been attempted before, but satellite and user terminal costs were too expensive for mass market acceptance, and the services languished. Now, with the continually diminishing cost of sophisticated electronics, and the ability to use low-cost, low-earth orbit satellites, the commercialization of space communications for mass market use is on the threshold of being realized. STARSYS is a leader in the effort to bring two-way space-based data communication and positioning at an affordable cost to people and businesses around the globe. The STARSYS system, our market perspective, and where we stand in implementing our system for low-cost data messaging and positioning by satellite is the subject of this paper

Millimeter wave satellite concepts. Volume 1: Executive summary

The objectives of the program were: (1) development of methodology based on the technical requirements of potential services that might be assigned to millimeter wave bands for identifying the viable and appropriate technologies for future NASA millimeter research and development programs, and (2) testing of this methodology with user applications and services. The scope of the program included the entire communications network, both ground and space subsystems. The reports include: (1) cost, weight, and performance models for the subsystems, (2) conceptual design for point-to-point and broadcast communications satellites, (3) analytic relationships between subsystem parameters and an overall link performance, (4) baseline conceptual systems, (5) sensitivity studies, (6) model adjustment analyses, (7) identification of critical technologies and their risks, (8) brief R&D program scenarios for the technologies judged to be moderate or extensive risks

Commercial Application of EYESAT

With the continued growth in geosynchronous satellite communications transponders today, why could anyone consider using a low earth orbit, low data rate, limited availability satellite? Several factors have proven to be important as our experience with small, low earth orbit satellites increases: user priority, simple access, low investment cost, portability, global reach, and flexibility in meeting specialized requirements. The purpose of this paper is to describe some of the potential commercial applications of the AMSAT Microsatellite. Four of these spacecrafts are currently in sun-synchronous orbit, being tested and used by amateur radio operators around the world. Interferometrics Inc. of Vienna, VA has been licensed by AMSAT to commercialize the Microsat technology. Several system concepts using the basic Microsat bus have been developed to meet user requirements. The combination of a small, proven, inexpensive satellite; affordable launch costs; portable, user-friendly ground terminals; and simple, on-orbit operations make these concepts extremely attractive to a number of potential customers

A burst compression and expansion technique for variable-rate users in satellite-switched TDMA networks

A burst compression and expansion technique is described for asynchronously interconnecting variable-data-rate users with cost-efficient ground terminals in a satellite-switched, time-division-multiple-access (SS/TDMA) network. Compression and expansion buffers in each ground terminal convert between lower rate, asynchronous, continuous-user data streams and higher-rate TDMA bursts synchronized with the satellite-switched timing. The technique described uses a first-in, first-out (FIFO) memory approach which enables the use of inexpensive clock sources by both the users and the ground terminals and obviates the need for elaborate user clock synchronization processes. A continous range of data rates from kilobits per second to that approaching the modulator burst rate (hundreds of megabits per second) can be accommodated. The technique was developed for use in the NASA Lewis Research Center System Integration, Test, and Evaluation (SITE) facility. Some key features of the technique have also been implemented in the gound terminals developed at NASA Lewis for use in on-orbit evaluation of the Advanced Communications Technology Satellite (ACTS) high burst rate (HBR) system

Technology requirements for communication satellites in the 1980's

The key technology requirements are defined for meeting the forecasted demands for communication satellite services in the 1985 to 1995 time frame. Evaluation is made of needs for services and technical and functional requirements for providing services. The future growth capabilities of the terrestrial telephone network, cable television, and satellite networks are forecasted. The impact of spacecraft technology and booster performance and costs upon communication satellite costs are analyzed. Systems analysis techniques are used to determine functional requirements and the sensitivities of technology improvements for reducing the costs of meeting requirements. Recommended development plans and funding levels are presented, as well as the possible cost saving for communications satellites in the post 1985 era