Click for next page ( 37

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 36
WORKING PAPER SECTION 4 THE ACQUISITION COST OF A UHF DBS-A SYSTEM-SERYICE Estimating the financial and economic future is at least as difficult and tentative an undertaking as predicting the future of technological development and the listening interests of radio broadcasting audiences. But it seems reasonable to predict that the cost of providing the services described here, in the manner outlined, can be rationally estimated to within a factor of 2X or so, and that is sufficiently instructive to serve the purposes of this paper. The Surf ace Segment The potent) al market i s enormous. Several hundreds of mi l l i ons of spacewave receivers eventually could be expected to be purchased to replace those now in use to receive shortwave programs. Purchases also should be induced not only by the increased reliability, quality, and clarity of signal reception compared with today's shortwave services, but also by the ability to listen to many more program channels broadcast by the governments of countries all over the world, and perhaps by the prospect of listening to commercial broadcasting--altogether, a global initial purchase market of $10-billion. Thus, were the communications industry to believe that deployment of one or more space segments was in the offing, the industry could be expected to meet the development, production, marketing, distribution, and sales costs of the required new receivers. The purchase price of a Standard Service spacewave receiver need be no more than a few tens of dollars, i.e., the retail price of today's handheld and kitchen table AM and FM receivers The only novel features would be accurate and stable channel tuning, a low-noise front end and a different looking small antenna. So, even though the cost to produce, install, and use the surface segment of the overall system would be greater than the space segment by at least an order of magnitude, there would be good reasons to expect that its users would be able to, and would, make such a large overall investment; that providing the receivers would require little that would be novel to the communications industry; and, indeed, that there would be a great economic incentive for the industry to do so rapidly. The Soace Seument The present U.S. Federal Government Advanced Communications Technology Satellite (ACTS) and its anticipated rural mobile, satellite-to-satellite optical, surface-to-1 2-mile-high aerostat powered platform (HAPP), Milstar and Strategic Defense Initiative (SDI) R&D programs, and commercial DBS-TV development programs, should inferentially underwrite the bulk of the basic technological developments needed for space segment transmitters, switches, and space power sources, and the exploration of the operational - 36 - WORK] NO PAPER

OCR for page 36
WORKI NG P APER characteristics of dynamically programmable, multichannel, multibeam, geostationary, UHF, SHE, and EHF transmitters.22 The U.S. civilian Space Station, inclusive of both lower orbit Orbital Maneuvering Vehicles (OMV's) and higher, even encompassing geostationary orbit (GEO), Reuseable Orbital Transfer Vehicles--ROTV's, the Hubble space telescope, the Space Industries, Inc., "space factories," and the SD] R&D programs (and, quite possibly a new surface-LEO booster, a geostationary space "platform," and Lunar and/or Mars exploration programs)), in conjunction with use of the Shuttle fleet, and European Space Agency programs such as Columbus, would inferentially underwrite the development of in-space infrastructure. This support would allow large and sophisticated space structures to be assembled and tested in low-Earth-orbit (LEO), the development of economical satellite servicing assets and operations, and significant reduction in the unit cost of surface-to-LEO and surface-to-GEO space transportation. The existence and use of such permanent, sophisticated, in-space infrastructure, including technicians, will speed the introduction of advanced space communications technology and lower its unit costs generally by easing the conduct of in-space development programs and allow for the repair and updating of operating in-space assets. The assumption is made that four separate space segments would be required to provide adequate surface coverage on a worldwide basis (two for North, Central, and South America, and the eastern Pacific Ocean; two for Europe, Africa and Asia, the Indian Ocean, and the western Pacific Ocean). It is important to appreciate that this number would constitute a quasi-production run of essentially identical spacecraft (although the number of beams and their pointing directions would vary satellite-to-satellite as would the pointing direction of the satellite-to-satellite optical or millimeter wave program transfer circuits, etc.~. This would allow significant production learning curve efficiencies to be obtained and allow the total acquisition program engineering financial costs to be spread over a multiple satellite procurement. Another assumption is that the space segments would be designed and constructed to be able to have their parts packed for surface-to-LEO shipment aboard several Orbiters of the Shuttle fleet in a most compact and efficient fashion so as to obtain the lowest price for the overall shipment. Delivered to LEO over time, the parts would be off-loaded from the Orbiters and temporarily stored on the Space Station. One-by-one they 22. See "Satellites and mobile phones: planning a marriage," Alex Hills, IEEE Spectrum, pages 62-67; August, 1985. This article reviews NASA's aspirations for an R&D program that would involve a large and sophisticated space segment and small surface receivers to provide two-way audio communications in low population density areas. The space segment would have a large parabolic antenna, multiple spot beams, a high DC power and would operate in the UHF spectrum region. The receiver would have a low-noise front end and a modest antenna gain. - 37 - WORKING PAPER

OCR for page 36
WORKING PAPER would be assembled there by appropriate Space Station technicians, tested in LEO, and then sent on their way outward to their intended final geostationary orbital locations.23 Finally, each space segment might be able to take up its position on or near a geostationary space focal point, or "platform," where they would share basic services such as orbit adjustment engines, fuel, telemetry, electrical power, basic stabilized structural framework, and visiting maintenance crew quarters with other space platform occupants. Other such occupants could be transceivers used for long-hau] trunk, mobile, teleconferencing and DBS-TV communications; navigation and position-fixing transceivers, increasingly sophisticated passive and active radiowave and optical Earth-directed remote sensing instruments, and sophisticated astronomy instruments. Whether or not this possibility occurs cannot be clearly predicted now because NASA's geostationary space "platform" aspirations are still in the study stage, not the commitment-to-develop stage. Within the context of these assumptions, a system's space segment would cost roughly less than $200 million, as detailed below. 23. Perhaps it could go without saying that space-related economic competitive drives in other countries as well as the U.S. could modify such assumptions and lower the costs estimated here. - 38 WORKING PAPER

OCR for page 36
WORKING PAPER Space Segment Cost Estimates--Major Components Item Cost (mi1lions of U.S. dollars 1985) .. Components Antenna DC powe r Switch Upper Stage 11 Busll Power amplifiers, drivers, etc. Insurance, per sate] ~ ite Launch to LEO 4 ~- 5. In-orbit parts storage, assembly, and test Space segment surface feeder station 6. Surface signal monitoring network TOTAL 20 30* 10 10 10* 20 10 40+ 10 10 10 $180 * Both the cost of the DC power and the bus could be reduced by a factor of 2 or more for any DBS-A space segment that shared a geostationary space "platform" with other space assets and services. For instance, a geostationary DBS-A space segment would need a maximum of electrical energy during the pre-workday AM hours and the post-workday PM hours, while a long-haul trunk space segment needs the most electrical energy during the work day. + The equivalent of half of a full shuttle flight at $80 million each. - 39 - WORKING PAPER

OCR for page 36
WORKING PAPER Each subsequent space segment would cost $160 million on this same basis. Therefore, the total acquisition cost of the space segments of a global system-service would be: $~80 + (3~$160) = 5660 million. Considering both the judgements and approximations that had to be made in the circuit power budget, expected learning curve savings, and the possible cost savings that sharing geostationary services at space "platforms" would allow, it seems reasonable to round off the total cost to 5500 million. It should be reemphasized that the UHF space segment outlined here is a truly sophisticated one that would challenge communications and space engineers. While anticipated space-related technological developments offer a clear promise that its operational and cost goals could be attained, a relatively early regional system-service implementation could be initiated with greater confidence with a less sophisticated space segment. If the space segment antenna were scaled down from the 200-foot diameter suggested to 60 feet, or a frequency in the upper UHF TV region employed rather than the illustrative 2.5 GHz, then a system-service channel capacity reduction of some BOX would ensue. This arrangement would still provide a very respectable capacity for an initial service to be established within the next decade; it would not present the technical challenge and risk posed by a transmitter with lOX the antenna aperture area and lOX the number of subtransmitters; and it would result in an initial financial cost estimate of $30 to 50 million less for each satellite. Such a lower capacity initial regional system-service could be acquired at a cost estimated to be $130 to 150 million, rather than the $~80 million estimated for a large capacity system-service. An initial worldwide network of four such regional systems for an estimated gross cost of $100 to 200 million less than that estimated for the higher capacity system service. Again, it should be noted that such early cost estimates, made before detailed studies of service standards, system operating margins, overall system-service sizing, actual development of sophisticated in-space antenna, sub-transmitter and switch technology, and the actual installation and test of in-space spacecraft assembly and service infrastructure (i.e., a civilian Space Station), must be considered as preliminary and not accurate to more than a factor of two. WORKING PAPER