Chapter 3: Navy Tactical Applications for Space Emerge in the 1970s
The Navy's pioneering participation in space in the late 1950s had been primarily as part of the U.S. scientific race against the Soviets, although with an eye toward potential military benefits. Most Navy scientific work in space was turned over to NASA with the Vanguard program in 1959.
3.1 Soviet tactical exploitation of space alerts U.S. Navy, 1967-1972
In the late 1960s the Soviets began fielding space systems that were aimed not at the U.S. homeland, but against the U.S. Navy. The sections that follow provide an overview of Soviet naval-related developments in the 1960s and 1970s that is essential to understanding U.S. Navy responses.
3.1.1 Soviet antiship cruise missiles
At the end of World War II, the Soviet Navy was essentially a coastal-defense and ground forces-support service. Since it was not politically, economically, or technically feasible during the immediate postwar period to build a large ship seaborne Strike Force such as that of the U.S. and its NATO Allies, the Soviets took as their model the Japanese "Kamikaze" manned aircraft that had proved so successful in the final phases of W.W.II. Thus, a remotely piloted, unmanned antiship cruise missile program was developed into a formidable capability by the 1970s.
3.1.2 Soviet ELlNT ocean surveillance satellites
3.1.3 Soviet ocean reconnaissance RORSATs and EORSATs
3.1.4 Soviet navigation and communications satellites
The Soviet Navy began to use navigation satellites in 1970, in consonance with their breakout from a strictly defensive role to become a worldwide naval power. At that time there also was a nearly six-fold increase in the number of Soviet communications satellites used for naval long haul communications.
3.1.5 Soviet ASATs
3.1.6 U.S. Navy's net tactical situation vis-à-vis the Soviets space systems, in the early 1970s
3.1.7 Navy's need for a tactical-support space initiative
The U.S. Air Force, which had sole responsibility for acquiring U.S. military space systems, was focused almost exclusively on national intelligence and strategic defense priorities and was doing little to address Navy requirements for space-based support.
This situation was exacerbated when funding for all DOD space programs plummeted by 20% in 1970, and was down to about 60% of its 1969 level by 1972. In any case, Air Force decision-makers did not respond to the Navy's expressed concerns over Soviet ocean-reconnaissance and ASAT threats or the Navy's needs for space-based tactical communications and targeting support.
3.1.8 Letting the space-systems acquisition directive revised, 1970
In 1967, Admiral Thomas Moorer, Chief of Naval Operations, directed OP-098 to conduct a review of Navy space programs. This review produced two specific recommendations: (a) that a stronger Navy commitment to exploring the potential tactical applications of satellites was imperative; and (b) that the Navy needed to be bolder in translating fleet requirements into a space policy. Admiral Moorer responded to these recommendations, in part, by creating a new staff position, the Director of Navy Space Programs (OP-76). [Note: The new position was placed under the Director of Navy RDT&E (OP-07) in order to comply with the 1961 DOD Acquisition Directive limiting Navy space activities to research.]
To fill this new position, CNO selected Rear Admiral Bill Moran. The two officers had been stationed at China Lake together when the first Soviet Sputnik was launched and had discussed the potential naval applications of satellites. Rear Admiral Moran subsequently "pestered" Admiral Moorer on several occasions as to what the Navy was doing about getting a Navy space program started. As CNO, Admiral Moorer directed his former shipmate to "get the Navy started again on a space program" .
A 1969 Presidential Space Task Group review of NASA and DOD space programs, in which the Navy was an active participant, recommended that the DOD investment in satellite systems be at least doubled. With the Vietnam conflict consuming a growing share of the defense budget, the recommendation was rejected.
The Navy proceeded on its own to the extent that policy would permit, however, by creating the Navy Space Project Activity as a formal interface between the Navy and the National Reconnaissance Office.
In 1970, RADM Fritz Harlfinger, Director of Navy Command and Support Programs (OP-094), joined with his peers in the Army and Marine Coops in a concerted effort to overturn the stifling 1961 DOD Acquisition Directive. Their efforts struck a responsive chord with Deputy Secretary of Defense David Packard, who cancelled the 1961 Directive and issued a new DOD Directive 5160.32 in 1970. Under this new polity, all services were permitted to develop space systems, with oversight by the DOD Deputy Director of Research and Engineering.
3.2 Strengthening the Navy's space organization
The Navy took immediate advantage of the new DOD space acquisition policy: six weeks after Secretary Packard signed the new Directive, Rear Admiral Harlfinger (OP-094) obtained DOD authorization to develop a Fleet Satellite Communications System in response to urgent fleet requirements for global communications. (See Section 3.3.4, for details of this effort.)
After a decade in the relative backwaters of space development, however, the Navy needed to revitalize those staff functions required to sponsor, develop, and manage satellite systems.
3.2.1 OPNAV space program sponsors
In 1971, the Navy consolidated responsibility for identifying and validating requirements for satellite systems by establishing the Space Programs Coordinator (OP-094W. Rear Admiral Lloyd Moffit was assigned as the first coordinator. Rear Admiral Moffit was an excellent choice for this assignment based on his previous involvement in developing the so-called "moffit matrix" which had been used in getting ocean surveillance requirements recognized as a national intelligence objective by the U.S. Intelligence Board.
In 1974, CNO divided responsibility for sponsorship of Navy space systems between OP-094 (for satellite communications) and OP-095 (for space-based surveillance).
In 1978, three separate efforts were undertaken to evaluate the effectiveness of Navy efforts in using space systems: (1) a Space Net Technical Assessment, sponsored by the VCNO, (2) a Navy Space Study, under the auspices of OP-094; and (3) a study by the Navy Space Panel of the Naval Studies Board of the National Academy of Sciences. These three efforts resulted in the following broad conclusions:
- Soviet satellites represented a major threat to the U.S. Navy and prudent measures should be undertaken to counter any tactical advantages the Soviets had gained by using space systems.
- Space matters should be recentralized within OPNAV and a corps of space-competent Navy personnel should be developed.
- The Navy was the largest user of space systems among the services, but had little influence within DOD concerning space matters.
3.2.2 Management of Navy space programs
Between 1971 and 1973, the Navy's approach to managing satellite programs went through several transformations, which are described briefly below.
3.2.3 OPTEVFOR detachment F/0-265
OPTEVFOR Detachment Sunnyvale was established as OPTEVFOR Det F/O 265 in 1972 to support a series of ocean surveillance and tactical intelligence exercises in the Pacific ocean area in the early 1970s. These exercises, which culminated in exercise OUT LAW HAWK in 1975, were for the purpose of evaluating the ability of Navy intelligence and operations personnel to receive, assimilate, and evaluate intelligence from U.S. low-orbiting surveillance satellites and other "non-organic" sources (U-2s and SOSUS) for tactical use.
OPTEVFOR was directed by CNO to provide objective operational assessment of the intelligence sources, procedures and equipments used to compile a tactical ocean surveillance product, and most importantly, to assess the value of that product to battle-group commanders. To execute this assignment, RADM Red Carmody created a detachment in Sunnyvale, California. OPTEVFOR Det Sunnyvale became OPTEVFOR's primary source of expertise to evaluate these systems, and the tactical procedures for their use. A number of systems were under Navy development at that time to aid in the exploitation of information from the satellites and other sources (e.g., Ocean Surveillance Information System (OSIS), Tactical Flag Command & Control Center (TFCC), and the Tomahawk Weapon Control Station (TWCS)). OPTEVFOR Det Sunnyvale was disestablished in 1989 as these systems transitioned to operational use.
3.3 Satellite communications for the U.S. fleet
3.3.1 Navy communications requirements in the 1970s
During the period between the end of WWII and the fleet introduction of satellite communications, the Navy had relied on MF/HF radio for long-haul communications at sea, and on land lines between stations ashore. Although the MF/HF radio had worked effectively for years, it had limitations. Surface-to-surface propagation was affected by ionospheric and atmospheric variations, and these frequencies were vulnerable to intercept and geolocation from great distances. Additionally, a network of MF/HF radio stations had to be set up ashore to support operations at sea in each theater.
At the end of the Korean War, the number of Navy personnel assigned to shore-based communications stations overseas was reduced significantly. In 1973, there were still twenty-nine Navy communications stations located throughout the world, but for economic reasons the number had to be reduced again.
DSCS satellites could solve problems the Navy might have with long-haul communications ashore, but DSCS could not replace MF/HF for long haul communications afloat, because the DSGS antennas were too big for aircraft, submarines, and most surface ships. For tactical communications among ships and aircraft, the Navy was dependent on UHF-band radio. The problem was that UHF is limited to line-of-sight links, and could not be used between units over the horizon from each other, unless an airborne relay was available. The global expansion of U.S. Navy responsibilities, to counter a growing Soviet naval threat, created an urgent need for UHF satellite communications.
3.3.2 Navy satellite communications organization
As described in section 3.2 above, sponsorship of Navy satellite communications programs resided in OP-094 beginning in 1971. Similarly, by 1973 management of Navy satellite communications programs had been consolidated within PME-106 under NAVELEXSYSCOM.
Three naval laboratories also supported the Navy satellite communications effort: the Naval Research Laboratory in Washington, DC; the Naval Electronics Laboratory Center (today, NRaD) in San Diego, California; and the Underwater Sound Laboratory (USL) in New London, Connecticut. By informal agreement among these laboratories, NELC was responsible for developing the Navy's satellite communications terminals, and NRL concentrated on the modulation techniques to be employed in satellite communications. The USL provided technical input and antenna design expertise for submarines.
3.3.3 Controversy over frequency bands
At this time, there were many honest, and strongly held, differences of opinion concerning the "proper" frequency band for tactical satellite communications. Proponents for UHF, SHE, and even EHF satellites offered well-reasoned arguments for their favorites.
UHF communications satellites would provide the greatest area of coverage to users on the surface equipped with relatively simple antennas. This concept had obvious appeal to tactical users. The UHF spectrum did not offer much opportunity for anti jamming techniques, however, and was the least capable of the three bands in terms of capacity.
At the other end of the spectrum, EHF communications satellites could provide very high capacity and exceptional anti jam resistance. EHF antennas could also be quite small. The downside was that EHF satellites would generate very narrow communications beams that would have to be pointed directly at individual or small groups of users on the surface and that high capacity EHF terminals would be large, complex, and expensive.
The DOD Plan. The Military Satellite Office (MSO) of the Defense Communications Agency recommended that satellite communications systems be pursued in all three frequency regimes: EHF, SHF, and UHF. The three system approaches recommended by the MSO were:
- Initiate a satellite communications system for use by general purpose forces. (This became FLTSATCOM, which used mostly UHF, but also SHF for the uplink of its shore-to-ship broadcast component.)
- Continue the DSCS satellite communications system (SHF), for "logistic" communications.
- Initiate a satellite communications system emphasizing jamming resistance, physical survivability, and a capability for the uplinks to be covert; for use by strategic and other high-command applications. (This led to Milstar, which is mostly EHF, but has some UHF channels.
3.3.4 UHF and the FLTSATCOM
Among all the services, Navy was most impressed by the UHF tactical communications demonstrated during the tests with LES-5/6 and TACSAT-1. As a result, the Navy submitted a plan to develop UHF tactical communications satellites in 1971.
On 27 September 1971, the Deputy Secretary of Defense approved the development of the Fleet Satellite Communication (FLTSATCOM) system. The Navy, which provided the requirements and funding for the system, was designated overall program manager. The Air Force was assigned to develop the satellites, provide for their launch and on-orbit control, and to develop airborne terminals. The Army was made responsible for the ground terminals. Navy became responsible for shipboard terminals.
As envisioned by the Navy, the Fleet Satellite Communications (FLTSATCOM) system would provide communications support to the fleet, worldwide (except for the near-polar regions), by means of four geosynchronous satellites arranged around the Earth's equator. A special transmitter/receiver package riding on the FLTSATCOM satellites, called AFSATCOM, would provide communications for Air Force long-range bombers. The solar-powered, three-axis-stabilized FLTSATCOM satellites, would each weigh a little over a ton and would be launched by Alas-Centaur.
Once the FLTSATCOM concept-definition phase got started, many potential users began to submit requirements-not only the military services, but also the State Department and White House. The demand for channel capacity grew, to the point that the growth in communications payload weight threatened to exceed the booster lift capability. Requirements had to be prioritized and resolved .
The FLTSATCOM satellite system proposed by Navy and approved by DOD had the following communications subsystems:
- One channel for the Fleet Satellite Broadcast, a one-way broadcast from Navy communications ashore to commanders and units afloat (SHF uplink and UHF downlink)
- Nine UHF channels for Navy use, including:
-two channels for secure voice
-one channel for the Naval Modular Automated Communications Subsystem (NAVMACS) and the Common User Digital Information Exchange Subsystem (CUDIXS), for ship-to-shore and shore-to-ship transmission of teletype and other addressed messages (essentially to replace the MF/ HF ship-to-shore and ship-to-ship communications)
-one channel for the Tactical Intelligence (TACINTEL), broadcast, a one-way broadcast of special intelligence (SI) data from Ocean Surveillance Information System (OSIS) nodes ashore to commanders and units at sea
-one channel for the Officer in Tactical Command Information Exchange Subsystem (OTCIXS), a two-way automated data net interconnecting battle-group unto for purposes of tactical battle coordination and over-the-horizon targeting
-one channel for the Submarine Satellite Information Exchange Subsystem (SSIXS), an automated data net linking submarines at sea with support facilities ashore
-one channel for a Tactical Data Information Exchange System (TADIXS)
-and two spare channels
- Twelve channels for Air Force Satellite Communications (AFSATCOM
- One channel reserved for JCS
- Some channels for classified users.
A Navy communications station ashore in each theater would transmit the fleet satellite broadcast and, where necessary, to interconnect FLTSATCOM with the Defense Satellite Communications System.
FLTSATCOM system operations would be controlled by the Naval Telecommunications Command Operations Center (NTCOC) at Washington. DC, supported by: Naval Communications Area Master Stations (NAVCAMS) at Norfolk, Virginia (Atlantic theater and Second Fleet), Finegayan, Guam (Western Pacific and Seventh Fleet); and Wahiawa, Hawaii (Eastern Pacific and Third Fleet); and by the Air Force Satellite Control Facility.
220.127.116.11 Development of the Navy UHF terminals
Navy's terminals for FLTSATCOM were developed by NAVELEXSYSCOM with technical input by the Naval Electronics Laboratory Center (NELC, now called NRAD) at San Diego, California, and the Naval Research Laboratory. The types of shipboard FLTSATCOM terminals were:
- AN/WSC-5, for installation ashore, (using the assets from the AN/WSC-1 development), produced by Rockwell International.
- AN/WSC-3, for installation in all Navy submarines, all surface combatants, and some naval aircraft (e.g., EP-3s), produced by E-Systems. The AN/WSG3 has a remarkable record for reliability, attaining a 15,000-hour mean-time between failures, and costs only about $25,000 per installation.
- AN/SSR-1, for shipboard reception of the Fleet Satellite Broadcast (for ships not equipped with the AN/WSC-3), produced by Motorola
- ON-143, FLTSATCOM data modem for exchange of tactical data.
18.104.22.168 Acquisition of the FLTSATCOM satellites
The Air Force assigned a program manager at Space and Missiles Systems Organization, Los Angeles AFS, CA for acquisition of the satellite's. The program office had a Navy deputy program manager and 10 military and civilian staff positions. Specifications for the satellites were drafted by the Naval Research Laboratory. Proposals were solicited, and the FLTSATCOM contract was awarded to TRW in 1972. The FLTSATCOM program became embroiled in controversy almost from its inception. By all accounts, major problems first arose when serious difficulties were encountered in isolating the satellite's several antennas from each other and with inter-channel interference [1, 4, 10, 12, 14]. The Air Force was of the opinion that the Navy, and NRL in particular, was not a team player and had its own agenda .
When the technical difficulties appeared, the Air Force called on the Aerospace Corporation to "fix the problem" with FLTSATCOM. One of Aerospace's first steps was to question NRL's specifications [1, 12].
For its part, the Navy began to grumble about Air Force management practices and, as costs climbed, Congress threatened to cancel the program . At this point, the Air Force capped the cost of TRW's cost-plus-fixed-fee contract forcing the company to invest in-house funds while pursuing solutions to problems not covered in the specifications [4, 14].
The isolation problems were solved by modifying the uplink and downlink antennas. A joint Air Force, Aerospace, NRL, and TRW team also developed solutions for the interchannel interference problem. A fire at TRW's facility resulted in a delay in production, however .
A more serious potential delay developed when the Air Force began to talk of phasing out its Atlas-Centaur booster, which was needed to put FLTSAT in a geosynchronous orbit [ 14]. The Navy became a very anxious at this point because heavy investments had been made in preparation for fleet introduction of FLTSATCOM. The Navy approached Congress with a concept for leasing commercial satellite channels until FLTSAT was available. Congress approved this concept, which is discussed in more detail below.
By this point, the relationship between the Navy and Air Force over roles-and-missions in space acquisition in general, and FLTSAT in particular, had deteriorated badly. Hostility between the Navy FLTSAT Program Office and the Air Force Program Office became so intense a the Air Force Program Manager was relieved [10, 14]. The Air Force made a happy choice in selecting Colonel Forest McCartney, USAF as the new head of its FLTSATCOM Program Office. Colonel McCartney brought strong credentials in satellite communications to the job and quickly established cordial working relationships with Vice Admiral Gordon Nagler, (OP-094) and Rear Admiral Earl Fowler at the Navy's Electronics Systems Command-both of whom were major proponents of the FLTSATCOM effort. Colonel McCartney also began a dialog on fleet requirements for FLTSAT with Commander Scott Monroe, the Navy Liaison Officer to his Program Office.
Improvements in the program, at both the personal and technical levels, were soon apparent Colonel McCartney also took on problems within his Air Force chain of command with such vigor that his growing cadre of Navy supporters feared for his career. There was widespread relief in Navy circles when McCartney was selected for Brigadier General .
The respect and good will fostered by Brigadier General McCartney paid big dividends when an eleventh hour routine reliability check uncovered possible welding flaws in FLTSAT wiring. Navy and Air Force quality assurance experts began to question the desirability of proceeding to launch of the first satellite. After detailed discussions, Brigadier General McCartney made the decision to proceed, and received strong endorsements from Admirals Nagler and Fowler .
The first FLTSAT was launched in February 1978, followed by FLTSAT #2 in May 1979. The full operational constellation of four FLTSATs was in place by October 1980.
22.214.171.124 Fleet satellite broadcast
When radios became standard equipment on U.S. Navy ships (in the early 1900s), communications depended on the use of medium frequency (MF) and high frequency (HF) portions of the frequency spectrum. MF/HF radios made it possible to communicate over great distances if sufficient power was available and atmospheric conditions were favorable. HF frequencies in particular, however, were vulnerable to enemy exploitation and jamming, from equally great distances.
When the concept of satellite communications was proposed seriously for fleet broadcasts, there was a strong desire to reduce the vulnerability of fleet communications to enemy activity jamming in particular. The Navy recognized that an ultra high frequency (UHF) broadcast from a satellite could reach a very large footprint on the surface of the earth and could be received by ships equipped with relatively simple omni-directional antenna systems. If an enemy attempted to jam a UHF satellite downlink, the hostile jammer would need to close within line-of-sight of the target ship. The Navy believed that conventional weapons could be employed by the fleet to destroy such a jammer.
If, on the other hand, an enemy attempted to jam a satellite uplink, it was possible that the broadcast could be knocked out. Of even greater concern, jamming could be directed against a satellite uplink from anywhere in the satellite's footprint-an area of approximately one quarter of the Earth's surface for a geosynchronous satellite. With these vulnerabilities in mind, NRL was directed to focus on methods for protecting the uplinks of the proposed communications satellites as the most effective means for increasing resistance to jamming.
NRL responded by developing a Fleet Broadcast Processor (FBP) which operated in the super-high frequency (SHF) portion of the radio-frequency spectrum. At SHF frequencies, engineers could take advantage of wideband, spread-spectrum modulation and the increased radiated power available from highly directional earthbound uplink antennas to provide a measure of resistance to jamming. When tests of the FBP proved the validity of the concept, NRL was directed to procure FBPs for the FLTSATCOM program. The Air Force, in its capacity as Program Manager for FLTSATCOM, levied a requirement that the FBP be hardened against nuclear attack. The radiation hardening was accomplished, although at great additional expense for the satellite segment of the FLTSATCOM system .
The FBP remains a core element of most military satellite communications operated by the U.S. today (including FLTSATCOM, LEASAT, UHF Follow-0n, and certain Navy DSCS applications. It is important to note that the SHF/FBP protects the fleet broadcast only. If two ships are talking to each other using UHF uplink and downlinks, this communication remains vulnerable to deliberate jamming (or unintended interference) from transmitters anywhere in the satellite's footprint.
126.96.36.199 Leasing the Gapfiller satellites
As a result of mid-1970s' uncertainties and delays in the acquisition of the FLTSATCOM satellites, Assistant Secretary of Defense for Command, Control, Communications and Intelligence (C3I), Eberhart Rechtin, approved a Navy request to procure UHF satellite communications capability directly through commercial sources. These "Gapfiller" satellites were to be used on an interim basis until the FLTSATCOMM satellites would become available. Congress approved the authorization.
The Navy contracted with Comsat General to lease UHF-relay channels on three of its MARISAT satellites which had been built for commercial maritime use. The Navy leased the UHF (225 to 400 MHz) channels, while Marisat's commercial users operated on the 1.5-1.9 GHz channels. In 1976, three UHF Gapfiller satellites were placed on operational service for Navy use. Special UHF terminals were provided for Navy use and were installed at first in only a handful of Navy combatant ships for high-priority use with the Gapfillers. The Gapfiller satellites provided point-to-point UHF communications service for the fleets for several years but did not provide the Fleet Satellite Broadcast or the Air Force Satellite Communications Subsystem. Gapfiller brought UHF satellite communications to the fleet for years before the military FLTSATCOMs came on line and proved satisfactory for the most essential of the fleet's tactical communications requirements.
3.3.5 Navy's development of SHF terminals for DSCS
Navy development of terminals for the DSCS continued through the 1970's. DSCS afloat terminals were intended only for installation in the flagships of major commands, whose commanders had to have access to the high-level communications and intelligence carried by DSCS, and whose flagship could accommodate the large directional antennas required by the SHF links of DSCS.
Following several aborted starts with SHF shipboard terminals for DSCS during the 1960s (see Section: 188.8.131.52), the Navy tried again with a contract awarded to ITT Corporation for development of the AN/WSC-2 SHF communications system. This undertaking turned out to be too costly and the installation too large for even the largest combatants.
Based on lessons learned from the AN/WSC-2 development, NAVELEX obtained permission from OPNAV to develop a simplified SHF terminal to reduce the size and cost of shipboard SHF terminals. The AN/WSC-6 was developed with dual antennas to obtain hemispheric coverage around the ship's superstructure; a pair of eight-foot diameter antennas for large combatants, and a pair of four-foot diameter antennas for smaller combatants. To further reduce cost in production, a single four-foot antenna was procured. Installations were limited to about thirty major flagships including aircraft carriers. These terminals were to provide the commanders of Battle Groups, Amphibious Ready Groups, and numbered fleets with high-level access to the DSCS net.
An anti-jam modulator-demodulator (modem) was developed concurrently with the AN/WSC-2 and-6 evolution, to provide an interoperable, anti-jam command link for Navy, Air Force, and Army commands. The OM-55 modem was developed for shipboard use to be interoperable with the AN/USC-28 modem developed by the Army and Air Force. The Navy's OM-55 incorporated robust forward error correction encoding to allow for signal losses during switching between the dual antennas, and a time-division mode for spectrum sharing with threat warning receivers on the ships.
During the 1970s, a requirement evolved to equip the Navy's eighteen SURTASS ships (essentially converted fishing boats which operated mobile towed arrays as part of the Navy's underwater sound system) with a wideband communications link to pass high-fidelity acoustic data ashore for near-real-time processing. The AN/WSC-7, a modified AN/WSC-6, was built by NRL to enable the SURTASS ships to utilize DSCS for this application.
3.3.6 EHF and MILSTAR
The Navy arranged with MIT's Lincoln Laboratories to explore the feasibility of providing a jamming-resistant communications capability for the Navy using the extremely-high frequency (EHF) portion of the radio spectrum. A proposal came forth for an EHF satellite communications capability that would use a combination of features to reduce vulnerability to jamming and direction-finding. These features included: (1) wideband spread-spectrum modulation, to provide a substantial link-margin advantage over any practicable jammer; (2) multiple spacecraft within sight, so users could select a satellite not being jammed; and (3) highly directional antennas, both at the surface and on the satellite, to provide an additional margin of protection against jammers outside the communications beam. The shorter wave lengths of EHF would permit directional antennas significantly smaller than those needed at SHF (for DSCS). The designers chose to employ a previously little used part of the EHF communications band, around 38 GHz.
When the EHF communications proposal was briefed, senior Navy planners liked the idea. EHF satellite communications would provide the fleet not only with an alternative in the event of jamming, but also, since the wideband spread spectrum links would not be detectable by conventional receivers, could provide U.S. submarines at periscope depth with a covert means of transmitting their communications. EHF communications would have additional advantages, such as providing an "order wire" to reestablishing other communications nets, including FLTSATCOM, if they were disrupted. Finally, wide bandwidths available at EHF would assure that high-level commanders would have all the communications capacity they needed .
The proposed EHF satellite communications system was supported by the national intelligence community which was looking for improvements over DSCS for moving critical information.
The EHF satellite communications capability proposed by the Navy did not involve development of a new satellite, but called for development of an EHF package (a concept which had already been demonstrated with the LES-series satellites) to be carried piggy-back on existing FLTSATCOM satellites.
The Chief of Naval Operations approved the proposal for an EHF satellite communications package and sent it on to the Secretary of Defense with a request for acquisition. With the request, the Navy earmarked $3 billion from its own funds for the acquisition. At this point, the Air Force intercepted the proposal and strongly objected to it. The Air Force proposed, instead, to fund the EHF satellite-communications acquisition entirely out of Air Force funds, as long as the Air Force was designated Executive Agent for the project. This offer, relinquishing Navy lead for Air Force funding, was accepted (although both services were to regret it later).
In 1974, the Secretary of Defense, with the concurrence of the military services, authorized the EHF satellite communications program (which was eventually named MILSTAR), under a joint program office headed by the Air Force. An acquisition review board was established under OSD (C3I) with representation by all of the services and the Defense Communications Agency (instead of the Air Force Systems Command, which usually provided acquisition review for Air Force programs). The Space and Missile Systems Center of the Air Force Space Division (formerly SAMSO) was assigned to develop and procure the MILSTAR satellites. Each service was to develop its own EHF terminals for MILSTAR, as had been the case previously with the SHF DSCS and the UHF FLTSATCOM acquisitions.
184.108.40.206 Acquisition of the MILSTAR satellites
Under Air Force management, significant changes emerged in the Navy's EHF anti-jam communications concept.
First, the Air Force derided to develop an entirely new satellite system rather than hosting EHF packages on existing satellites.
Second, under the joint program concept, the Air Force applied a "common user" approach for soliciting requirements from all the military services and national agencies. Requirements emerged for strategic military applications, tactical military applications, and intelligence-systems support. This composite of "common user" requirements, in fact, provide the acronym for the System's name: the Military Strategic, Tactical, and Relay (Milstar) system.
Third, the Milstar downlink frequency was changed to 20 GHz, to be compatible with the 20-GHz downlink of the DSCS-III satellites, and the uplink was changed to 44 GHz rather than 38 GHz as proposed by Lincoln Laboratories and the Navy.
Compromises were also made in the specifications, to accommodate all the requirements. To address some of the tactical needs of the services, for example, a number of UHF channels were added, but not enough to meet all the services' requirements. To satisfy strategic survivability requirements, satellite-to-satellite users links were specified.
The Milstar development made progress but proceeded slowly over years, experiencing many delays and escalating costs. Many of the problems resulted from changes in priorities and requirements among the large number of joint users. At one time or another, Milstar was touted as a replacement for the (strategic) DSCS system; as a replacement for tactical FLTSATCOM; or as a replacement for the intelligence-support relay communications.
In 1982, the issue of executive agent for acquisition of MILSTAR resurfaced. By this time the Air Force had sized and tasted a Milstar EHF satellite that purported to meet all of the common user requirements negotiated with the services (including survivability in a nuclear war). But the MILSTAR cost estimate had grown, accordingly, by a factor of five, and the Air Force lost its enthusiasm for funding it. At that point, the Air Force offered the executive service role as well as the program management position to the Navy. The only stipulation was that the Navy make the program manager's job a flag billet, assigned at Air Force Space Division in Los Angeles. Vice Admiral Gordon Nagler (OP-094) turned down the offer.
In the Mid 1980s, when the Air Force had not yet developed an EHF terminal for Milstar and there was as yet no Milstar satellite in orbit, Congress authorized the Navy to put a Lincoln Laboratories EHF package on FLTSATCOM satellites, as had been proposed originally, to provide an interim Milstar capability.
In the early 1990s, the Air Force attempted to cancel the Milstar program, using the end of the Cold War as the principal justification. By this time, however, the other services, and the Army in particular, had integrated MILSTAR too deeply into their communications architectures to abandon the project.
220.127.116.11 Development of Navy's EHF terminals
At EHF frequencies, it is possible to build highly directional antennas with very small physical dimensions. Part of the Navy's EHF satellite communications concept was equipping submarines with periscope-mounted antennas to permit low-probability-of-intercept (LPI) communications to SSNs and SSBNs. Ample funding for this effort was found in the Navy's strategic submarine budget.
Both the Naval Research Laboratory (NRL) and Naval Ocean Systems Center (NOSC) developed concepts for an EHF periscope antenna. The NRL design included a unique circular waveguide that is used in periscopes today as part of a submarine direction-finding system. NOSC teamed with TRW and developed a competing system.
The Naval Electronics System Command (PME-117) wrote a systems specification which incorporated elements of both the NRL and NOSC/TRW designs and solicited proposals from industry. Raytheon won the contract and developed both SSN and SSBN versions of the submarine EHF satellite communications terminal. Prototypes of both systems were tested using EHF packages on the LES-8 and-9 experimental satellites.
3.3.7 Satellite laser communications to submarines (DARPA)
In the mid-1970s, laser technology had matured to the point that it appeared feasible, technically, to use space-based lasers for communications. The Defense Advanced Research Project Agency (DARPA) proposed to conduct experiments with blue-green lasers which penetrated sea water to greater depths than other light frequencies. The concept was to develop a means for communicating to submerged submarines as an alternative to: EHF (which required submarines to raise a periscope to communicate), VLF (which required a trailing wire antenna), or ELF (which had a very low data rate).
The Navy was never enthused about this concept, but it struck a responsive chord in Congress and the Navy agreed to pursue the idea if DARPA could demonstrate a brass-board capability. DARPA's tests were successful in a narrow technological sense (messages were transmitted from an aircraft to a submerged submarine operating at depth, using a blue-green laser), but the submarine's location had to be known with such precision that the Navy was skeptical of any operational utility with an airborne system. Additionally, the technical risks and associated costs with developing a satellite laser communications system were significant.
The Navy attempted to stop the development effort but interest in Congress was strong and funds were inserted in Navy budgets to support research into such a system until the late 1980s. As the Cold War wound down, the concept of a laser satellite communications system was dropped.
3.4 Space-based navigation systems in the 1970s: improvements and proposed improvements to Transit
3.4.1 Transit during the 1970s
For three decades the Transit satellite system served as the satellite navigation system for the U.S. Navy (see figure 17). It was also, used by the Allied navies, and by the late 1970s thousands of merchant ships used Transit.
About 1970, the Navy asked the Applied Physics Laboratory to make the Transit system usable for protracted periods of time even if the ground stations were put out of service as a result of enemy action or system failure. This was called the "Transit Improvement Program (TIP)." TRANSIT satellites built before the improvement program were dependent on commands from a ground station, at least twice a day, to maintain their orbits with the desired accuracy and to control satellite systems. The TIP included development of a Disturbance Compensation System (DISCOS) of micro-thrusters to fine tune a satellites' orbit, and an on-board computer to control satellite systems.
Three satellites were developed and launched as part of the TIP effort (see Table 10). These experimental satellites were followed by a new series of operational Transit satellites called "Nova" . The DISCOS unit in TIP-I operated
Table 9. Transit improvement program (TIP) satellites
DISCOS unit in TIP-I operated excellently for 2-1/2 years until its supply of fuel was exhausted. In one experiment, the satellite position was predicted ahead for 90 days, and the error at the end of that time was only 300 meters. The solar panels for both TIP-II and TIP-III failed to open and the missions were aborted. On the basis of the success of the experiments with TIP-I, the Navy proceeded with Nova. The Nova satellite, which incorporated DISCOS, was launched on 15 May 1981. Navigation accuracy with Nova was better than with any of the earlier Oscars.
As a result of the TIP effort, Transit satellites could perform well for more than a week without interaction with a ground station. The initial navigational accuracy goal of the Transit system was half a nautical mile. As the system evolved, however, the accuracy improved to about 25 meters.
Transit was a very successful satellite navigation system, but it did have its limitations. The biggest shortcoming was the low number of satellites in orbit at any given time. Users could copy the signal from one satellite pass and derive a line-of-position on a chart. Users would then wait from several minutes to large fractions of an hour for a second satellite, to obtain a crossing line-of-position, and wait even longer for a third satellite to improve the accuracy of a fix. For submarines at periscope depth, such delays were agonizing. For aircraft or ships moving at high speed, the delays increased the uncertainty of position. A less significant, but arguably still important, limitation of Transit was its inability to provide a user with a three-dimensional fix (latitude, longitude, and altitude).
The Navy recognized early in the Transit program that adding satellites to the constellation, or raising their altitude, could help to minimize the delays in obtaining a fix. Solving the three-dimensional fix limitation would require a new concept-and NRL proposed a solution in the early 1960s.
3.4.2 NRL's Timation satellites
The Transit system depended on users receiving and measuring the Doppler shift of signals from a satellite in low-earth orbit.
A simple way to think about a time-based satellite navigation system is to picture a globe of the earth and imagine a satellite orbiting this globe. Extend this picture to include an expanding "bubble" with the satellite in the center. The radius of this bubble is equal to the distance travelled by a clock signal from the satellite until the signal is received by a user on the globe. In this simple system, the user is located in a circle defined by the surface of the globe and the intersection of the "bubble" with the globe. If a second satellite and its intersecting "bubble" are added to the mix, the user is at one of two locations where the bubbles intersect the globe and each other. If a third satellite is added, the intersecting bubbles define a unique three dimensional location for the user. As a practical matter, addition of up to four to six satellites in total provides a unique three dimensional position and velocity for a user in motion.
By the mid-1960s, the accuracy of electronic timekeeping devices had advanced to such a degree that separate clocks could be used, one on the user's platform and another in a satellite, to determine the distance from the satellite to the user based on the propagation speed of a radio signal between them.
The Naval Research Laboratory built the first high-precision clock for a satellite and demonstrated the feasibility of a satellite system using the measured distances from satellite to user based on radio transmission transit time. The first orbital test was accomplished with NRL's Timation satellite, launched on 31 May 1967 . NRL research with this satellite technology demonstrated that it was feasible to obtain three-dimensional position-fixing accuracies measured in tens-of-feet or better using a navigation satellite system.
3.4.3 Air Force's NAVSTAR/GPS proposal
In the early 1960s, the Aerospace Corporation came up with the idea of developing a satellite navigation system that could determine a user's position in three dimensions. In 1963, the Air Force Space Division funded further study of this concept by the Aerospace Corporation. A number of different technical concepts were studied, each based on measuring the time of arrival of signals from a cluster of satellites.
The concept for a satellite navigation system, or "global positioning system," that evolved from Aerospace studies was, like the Loran terrestrial navigation system, based on measurement of the time-difference-of-arrival of signals from pairs of satellites rather than absolute time measurements. Each satellite transmitter used the same system time, synchronized by a very precise clock and updated periodically by a controlling master ground station. The docks carried by the satellites would be sufficiently accurate that the satellite could continue operations for days without updates from the ground station.
For use in high-speed platforms such as aircraft, a minimum of four GPS satellites must be in view at all times to achieve desired navigation accuracies.
Extraordinary accuracies could be achieved with the envisioned GPS, down to tens of feet in all coordinates. It was also proposed that two sets of modulations be transmitted, one for very precise location (encrypted, for U.S. military users), and the other with somewhat degraded accuracies (for other users).
Aerospace (and in particular, a very able and persuasive engineer, Mr. Ivan Getting) promoted the GPS as a global navigation system to be used by all the services, and began a decade-long campaign to convince potential buyers of its military benefits. Mr. Getting was convinced that accurate, three-dimensional information would increase the accuracy of weapons delivery by bombers, improve close air support, and facilitate all-weather rendezvous of fighters with tankers. Even so, it was not easy selling GPS to the Air Forces-much less to the other services, including the Navy. The Air Force's Tactical Air Command was equipping fighters with Loran-C, and the Strategic Air Command was content to use existing inertial navigation aided by Doppler and conventional radars.
The Navy, which was operating the only satellite navigation system in the world at that time, TRANSIT, was well acquainted with the need to improve the accuracy of its system, especially for aircraft navigation. By the mid-1960s, the Navy had several efforts in progress to upgrade TRANSIT- upgrades that would have led to a GPS-like system if allowed to proceed to maturity.
The Naval Space Surveillance System radars developed by NRL in the early 1960s could not be calibrated accurately until ultra-precise satellite clocks were developed as a means for comparing ground radar and satellite Doppler signals. Mr. Roger L. Easton, an NRL engineer working on NAVSPACSUR calibration, proposed in April 1964 that ultra-precise clocks would also permit satellite navigation by "ranging" instead of Doppler shift.
The TRANSIT "Doppler" system of satellite navigation provided a user on the ground with one line-of-position for each pass by a low orbiting TRANSIT satellite. Successive lines-of-position formed a fix. While this technique yielded reasonably accurate fixes for slow-moving users (e.g., ballistic missile submarines) it did not work well for higher speed ships or aircraft.
Mr. Easton's concept was transformed into an experiment using a quartz-crystal dock in the Timation-1 satellite launched in May 1967 as part of the TRANSIT program. The Navy conducted the first test of satellite ranging in June 1967 under auspices of the Naval Air Systems Command. Following these successful tests, NAVAIRSYSCOM invited the Army and Air Force to join a Tri-Service Navigation Demonstration. This group conducted tests of the satellite navigation ranging concept January through June 1968.
In 1968, the three services set up a committee called the Navigation Satellite Executive Group (NAVSEG), to study the issue. Aerospace, and the indefatigable Mr. Getting, re-intensified the selling of GPS to the Air Force, which gradually became an advocate .
NRL's quartz-crystal dock worked in principal, but the system proved difficult to control in the cold of space, and the quartz was affected by radiation encountered in orbit. NRL adopted a new concept, the rubidium oscillator (the so-called atomic clock) as a technique for overcoming the limitations of quartz oscillators. Responsibility for this work was transferred from NRL to the Naval Air Systems Command in 1970, and was handed over to the Navy Electronic Systems Command's Navy Space Project Office (PM-16) in 1971.
A Global Positioning System Joint Program Office was formed in December 1973, under the leadership of Colonel Bradford W. Parkinson, USAF, to develop and acquire a new satellite navigation system based on the ranging concept. The launch of the Navy-built Timation IIIA satellite in July 1974, under the new name of Navigation Technology Satellite #1 (NTS-l), was the first test conducted under auspices of the new Joint Program Office. NTS-l also carried the new NRL rubidium time standard into orbit.
A GPS Clock Development Program was begun at NRI. As part of the joint CPS Program, in recognition of the exceptional work done by the laboratory in this area of space science and engineering. A new atomic clock, based on an ultra-precise cesium standard, was developed by NRL, and launched in NTS-2 in June 1977.
Fortunately for the future of the Navy's operating forces, the NAVSTAR/GPS program manager, Colonel Brad Parkinson, was a Naval Academy graduate who understood Navy tactical requirements. Colonel Parkinson agreed to a number of compromises in the GPS design in order to accommodate Navy's concerns, and by doing so he succeeded in winning over much of the Navy. These Navy-initiated compromises included:
- Putting the satellites in 12-hour orbits, rather than the 24-hour (synchronous) orbits proposed by Aerospace. The Navy was concerned, with good reason, that if funding for the NAVSTAR constellation was reduced the Air Force would position the satellite's to emphasize strategic coverage of the western hemisphere and perhaps Europe or Korea, rather than the ocean areas where the Navy operates. (The Navy-proposed 12-hour orbits automatically cover the whole world.)
- Using the existing Transit calculation facilities at Dahlgren, Virginia for the NAVSTAR/GPS ephemeris calculations, rather than expanding the Air Force facilities at Colorado Springs.
- Incorporating in NAVSTAR the highly accurate (and already tested) atomic clock developed by NRL for its Timation program.
The NAVSTAR/GPS system ultimately received approval from many elements of the services, but its funding always seemed at risk. As GPS was a common-user system, no one service wanted to be in the position of providing the major share of the funding. Air Force, with OSD backing, eventually forced the funding into the DOD budget. The Air Force contracted for NAVSTAR with North American-Rockwell. GPS gradually achieved operational status in the late 1980s and early 1990s, following major delays resulting from the loss of the shuttle Challenger and a late requirement to harden GPS against nuclear effects.
3.5 Navy ELINT ocean-surveillance system
By the late 1960s, the heavy Soviet investment in naval forces which followed in the wake of the Cuban Missile Crisis was beginning to bear fruit. The Soviets were launching large numbers of new ships and submarines, most of which carried anti-ship cruise missiles. Soviet maritime strike aircraft, also with anti-ship missiles, began showing up in naval exercises. And finally, the beginning of a well integrated ocean surveillance system- which included airborne and satellite reconnaissance assets-began to manifest itself.
The U.S. Navy's resources were, at the same time, heavily committed to the conflict in Vietnam. Ever mindful of the growing Soviet threat, however, the U.S. Navy began to look for ways to improve fleet capabilities in "blue water" operations.
3.6 Navy's continuing attempts to get a space-based radar ocean surveillance system in the 1970s
3.6.1 Satellite Ocean Surveillance System (SOSS)
The satellite ocean surveillance system (SOSS) effort began in the early 1970s with a new study of applicable radar technology. This study determined that a 60-foot circular parabolic antenna offered the most cost effective potential for a space-based radar for ocean surveillance. SOSS was envisioned as a four-plane, low-orbiting satellite system to track surface ships worldwide in all weather. The radar was a sweeping type system that searched along the ground track of the satellite. The system would take two looks, fore and aft, and perform range profiling and course and speed determination. SOSS also involved nuclear hardening, resistance to jamming, and an interface to the emerging Navy Command and Control System through FLTSATCOM.
To further validate the SOSS concept, the Navy commissioned detailed assessments by Navy laboratories, Federally Funded R&D Centers (FFRDCs), and two experienced industry teams. A minimum cost for the capability was determined to be on the order of $3.5 billion for a five-year life cycle. Research continued primarily at NRL, but two major aerospace teams also were brought in: TRW/Raytheon; and McDonnell-Douglas/RCA. The bulk of the funding was from OSD (ASD/I). OPNAV involvement and interest were minimal and little was done to get a planning wedge into the budget. The SOSS effort was terminated by mid-decade as Navy planners shifted priorities from the Soviet surface fleet to its growing submarine force. Affordability had also become a major issue and resulted in abandoning the concept of general ocean surveillance in favor of limited area surveillance and support for over-the-horizon targeting for cruise missiles.
3.6.2 XOS-19 and Crow's Nest
XOS-19 (Crow's Nest). When SOSS was terminated, emphasis was shifted to a concept more suited to monitoring of "choke points" and support for over-the-horizon-targeting. PME-106 called this concept Crow's Nest initially but the OPNAV staff felt the name was too revealing for a covert satellite system and the innocuous title XOS-19 was assigned to the project.
The XOS-19 project focused on a drastic reduction in cost, as compared to SOSS, in hopes that once a radar satellite was in orbit the information it provided would become so valuable that a full program would be authorized. XOS-19 was, therefore, recast as a research effort. Two expensive elements of the SOSS concept-radar scanning and on-board processing of radar data-were dropped in favor of a simple stating mode radar and less expensive ground processing. It was estimated that one prototype satellite could be built and launched for approximately $300 million. In the post-Vietnam conflict budget environment, however, even this smaller amount was not available and the project was terminated.
3.6.3 Clipper Bow
One of the tactical challenges the Navy began to ponder in the late 1970s was how the soon-to-be-introduced Harpoon and Tomahawk anti-ship missiles could be employed in a true over-the-horizon mode if the "shooter" did not have information on ships in the vicinity of the intended target-ships that might inadvertently be hit by a missile directed at a threat. In 1977, the Clipper Bow concept emerged as one possible solution to this targeting dilemma.
At the time the Clipper Bow concept reached maturity, however, the Soviet Backfire bomber, with its potent anti-ship missile, had emerged as a major threat to the fleet-a threat Clipper Bow could not address. Clipper Bow was terminated in 1979, primarily because the $600 million price tag was considered too high for a system that was limited to support of over-the-horizon targeting.
3.7 U.S. ASATs in the 1970s
3.7.1 1972 SALT treaty (prohibited U.S., but not Soviet ASATs)
The Strategic Arms Limitation Agreement of 1972 (SALT-I), between the U.S. and USSR, prohibited future interference with each other's 'national technical means of verification,' including reconnaissance satellites.
By the 1970s, the Soviets were operating RORSAT, EORSAT, and ELINT low-orbit satellites against the U.S. Navy and were regularly testing their ASAT interceptors in preparation for wartime use against U.S. low-orbiting satellites (including the Transit navigation satellite system).
The Soviets argued that low-orbit satellites comprised tactical support systems and were not "national means of verification." The U.S. (which at that time had no satellite reconnaissance systems exclusively dedicated to tactical support), insisted that all satellite reconnaissance systems constituted "national technical means of verification," and that an attack on any U.S. reconnaissance satellite, low or high-orbiting, would be considered a violation of the treaty and subject to appropriate retaliation.
Many people in the U.S. government made the argument that, since space systems were more important to the U.S. than to the Soviets, the U.S. should not threaten the Soviets with anti-satellite systems that might cause them to respond in kind. The fact that the Soviets already had an operational ASAT system, and were operating tactical satellites that directly threatened the U.S. Navy (e.g., RORSAT, EORSAT) was not compelling outside of Navy circles . The policy argument opposing the development of U.S. ASATs, which began under President Eisenhower, governed U.S. ASAT policy until the last days of President Ford's administration. President Ford reversed this policy in February 1976 when the Soviets resumed ASAT testing after a four-year hiatus. .
The Carter administration in 1978 pursued the so-called "twin track" policy with regard to ASATs: attempting to reach an ASAT arms control agreement with the Soviet Union, but at the same time authorizing a U.S. ASAT development program to provide bargaining leverage during the negotiations, and insurance if the negotiations proved unsuccessful.
3.7.2 Navy sea-based ASAT proposed
In the Mid 1970s, the Air Force re-initiated its ASAT program. New technology in guidance and infrared sensing allowed an inexpensive ASAT system to be conceptualized. The concept was to use F-15 aircraft to launch an existing missile, with a new second stage to loft a sensor package (about the size of a tomato juice can) with enough accuracy to intercept Soviet low earth orbiting satellites. The kill- mechanism was via kinetic energy upon impact; there was no explosive warhead. The F-15s were to be based on both East and West coasts of the United States, and upon orders to intercept, would take off and fly to a weapons release point and release the missile-all under computer control.
In parallel with the Air Force development, the Naval Air Systems Command was working with Air Force Systems Command to develop a system to launch the Air Force missile from carrier-based F-14s. This was the status quo as the CNO and his staff took up the issue of ASATs in 1982.
Over a three month period, the OPNAV staff reviewed the USAF ASAT and potential alternative concepts that included: (1) the F-14 launch of the ASAT missile and interceptor; (2) the interceptor in lieu of a nuclear warhead on a SM-2N missile launched from an Aegis cruiser, and targeted using the AEGIS weapons control system; and (3) the interceptor in lieu of the nuclear warheads on Poseidon missiles, launched from SSBNs, and targeted with the modified AEGIS system.
CNO turned down the Air Force offer to take over the air-launched ASAT program. After a determination that the ASAT mission was not part of the Navy's roles and missions.
All work on proposed sea-based launch of ASATs was also terminated at this time.
3.7.3 Navy countermeasures against Soviet satellite surveillance
In the absence of any weapon to use against Soviet ocean surveillance satellites, the fleet began to explore a wide range of potential doctrinal responses to reduce vulnerability of U.S. units to spacebased surveillance. The primary tools employed against Soviet surveillance involved traditional operations security (OPSEC) techniques such as emissions control.