Return to Naval Historical Center Homepage
1.1.1 Naval Research laboratory's space probes
The Naval Experimental and Research Laboratory was authorized by Congress on 4 March 1917, and its construction began on 6 December 1920 on the Potomac River about two miles from Washington D.C. The name was changed to Naval Research Laboratory in the mid-1920s.
In 1944, toward the close of World War II, the Naval Research laboratory established its Rocket-Sonde Research Branch to explore the upper atmosphere. This step toward outer space was the first such program in the United States. The NRL tests were designed to measure and study solar and cosmic radiations in the upper atmosphere, primarily to better understand their effects on Navy communications and help predict usable MF/HF channels.
In 1946, NRL together with other scientific agencies including the Navy associated Applied Physics Laboratory was offered the use of some of the captured German V-2s. Engineers and Scientists at NRL equipped V-2 rockets with instrumentation for probing radiation in the Earth's upper atmosphere. On 28 June 1946, NRL launched the first of these missions. The rocket, which reached an altitude of 67 miles, carried radio transmitters for telemetry transmissions, a spectrograph, pressure and temperature gauges, and a geiger counter telescope to probe for cosmic rays. Between 1946 and 1952, NRL launched sixty-three V-2 rockets, most of them from White Sands, New Mexico. The rockets carried over 20 tons of scientific instrumentation to altitudes ranging between 50 and 100 miles.
Once all the V-2s were expended, the Navy's solar radiation research continued first using new sounding rockets and finally satellites.
1.1.2 Applied Physics Laboratory's space probes
Military work at the Applied Physics Laboratory (APL) of the Johns Hopkins University began during World War II when a small group of scientists and engineers designed a very successful proximity fuze for U.S. antiaircraft guns. (Over time, APL was involved in developing the Polaris ballistic missile system, the Terrier, Talos, and Tarter antiaircraft missiles, the Tomahawk antiship cruise missile, and the Aegis system for fleet air defense.)
World War II naval operations had involved heavier use of communications than had been normal in pre-war years and the Navy discovered that the upper atmosphere had significant impact on long range communications. Because the mechanisms that affected communications were not well understood, and could not be predicted reliably, Navy-sponsored, post-war research was directed toward learning more about the upper atmosphere. Part of this effort included work, using captured German V-2 rockets, by APL, under the direction of James Van Allen.
The V-2 could reach an average altitude of 70 miles and a maximum altitude of 114 miles, but the rocket could not remain in the upper reaches of the atmosphere more than a few minutes. To obtain the data Van Allen wanted, the rocket had to rise more than twenty two miles above the earth, and from the time it passed that level on the way up until it came hurtling back down, the instruments had only about five minutes to obtain their data. During that brief time, data from particle counters were recorded on rotating steel cylinders in the rocket's nose and were transmitted via telemetry to receiving stations on the ground. Since the rockets crashed when they returned to earth, the steel cylinders were constructed to withstand extreme conditions. One V-2 nose cone was lost in the desert for nearly two years before it was finally recovered and its data retrieved.
Van Allen and his team of APL physicists proved particularly adept at designing experiments to take advantage of the limited window of opportunity provided by the V-2s. On July 30, a rocket bearing APL instruments soared a hundred miles above the Earth's surface, setting a high-altitude record and bringing back a wealth of information about the cosmic ray particles that constantly bombard the earth. According to Van Allen's findings, secondary particles (known as mesons) formed by the collisions of cosmic protons with the Earth's upper atmosphere were far more abundant than previously believed and were especially concentrated at a height of one hundred thousand to two hundred thousand feet (the so-called "Van Allen belt").
1.1.3 Development of NRL's Viking Rockets
In the late 1940s the Naval Research Laboratory developed the U.S. Viking rocket as a replacement for the then-dwindling supplies of German-built V-2s.
The first successful launch of a Viking rocket took place at White Sands Proving Grounds in 1949. The next year, 1950, one of the Vikings was launched from the deck of the USS Norton Sound (AVM-1). It achieved what was at that time the record high altitude of 106 miles-almost high enough but not yet fast enough to put a payload into low earth orbit.
The Viking rocket was used extensively during the International Geophysical Year, 1957-8. The Vanguard rocket which placed the first Navy satellite in space was a derivative of the Viking.
The Navy's unused Viking rockets were transferred by NRL to NASA (with the Vanguard program) when NASA was formed in 1958.
1.1.4 Development of APL's Aerobee Rockets
Although APL continued to enjoy access to selected V-2 launches, the limited supply of these rockets persuaded the APL director to recommend that the Laboratory develop its own simpler, relatively inexpensive alternative. Such a project would also enable the Laboratory to obtain first hand experience with liquid rockets as potential guided-missile boosters. Under a Navy agreement with APL, the Navy's Bureau of Ordnance funded the project, APL provided the design and technical supervision, and associate contractors-in this case, Aerojet Corporation, Douglas Aircraft (later McDonnell-Douglas), and the Jet Propulsion Laboratory of the California Institute of Technology-performed the actual engineering and production work. The result was the Aerobee rocket, a twenty-foot-long, 1,650 pound liquid-fueled rocket, much smaller than the V-2 and capable of reaching a height of seventy-five miles at speeds of thirty-five thousand miles an hour (far higher and faster than the Army's Wac Corporal, the only other large American rocket in existence at that time.)
An Aerobee could carry a payload of 150 pounds in its eighty-eight-inch-long, pressure-tight nose cone. The first of these rockets was launched on November 24, 1947, for a flight of only thirty-five seconds. The second Aerobee launch on March 5, 1948, was highly successful, providing valuable new data on the intensity and distribution of cosmic rays above the appreciable atmosphere.
To provide a more expansive testing range in a variety of latitudes for both the V-2 and the Aerobee, the Navy converted a seaplane tender, the USS Norton Sound, into a seagoing rocket laboratory in 1948 and dispatched the ship to the Pacific Ocean. With its deck protected by a special metal sheath, the Norton Sound launched numerous APL rockets in 1948-49, obtaining through telemetry significant data on cosmic ray intensity and other atmospheric phenomena, including the dimensions of the ozone layer and the extent of solar radiation.
By January 1951, when APL's high-altitude program came to an end, APL had launched nine V-2 and twenty-one Aerobee rockets from sites around the globe.
1.1.5 Navy Satellite Communications Relay via the Moon
The U.S. Army's Signal R&D Laboratory bounced radar signals off the moon as early as 1946. The Army, concluded however, that nothing of military use would come of this work and ended the experiments. At the Naval Research Laboratory, Mr. James H. Trexler saw that the moon reflections might be useful in relaying military communications. Mr. Trexler's idea for a communications relay capability using the moon (Project Pamor-Passive Moon Relay) was funded by the Naval Security Group [1].
With NAVSECGRU funding, Trexler's development teams built a 60-foot-diameter antenna (actually a reflector-shaped hole in the ground), at Stump Neck, Maryland, and with NRL in-house funding proceeded to experiment with transmission and reception of signals off the moon. The feasibility of using moon reflections for communications was demonstrated successfully in 1951.
On 25 July 1954, using a 100-watt 220-megahertz communications transmitter, NRL transmitted the first voice messages via the earth-moon-earth path. Transcontinental communications were demonstrated in November 1955 when teletype messages were transmitted from Washington DC to San Diego, and two months later NRL conducted transoceanic communications via moon-satellite between Washington DC and Hawaii [2].
On the basis of these NRL experiments, the Chief of Naval Operations directed, in 1956, the establishment of the Communication Moon Relay (CMR) system for transmission of teletype and facsimile messages between Washington DC and Hawaii. In the Washington DC area, the transmitter was located at the U.S. Naval Radio Station, Annapolis, Maryland, see figure at left, while the receiver was located at Cheltenham, Maryland. The Hawaiian facilities were located at Opana and Wahiawa on the island of Oahu. The Washington DC and Hawaii terminals each used two 84-foot-diameter dish antennas-one for transmitting, the other for receiving.
1.2 Early competition over space development
The earliest U.S. studies of the feasibility of artificial earth-satellites after World War II were conducted by the Navy. The Navy's Bureau of Aeronautics formed a "Committee for Evaluating the Feasibility of Space Rocketry" on 9 October 1945, and the committee submitted a satellite development proposal to Bu Air, which tamed the proposal over to industry for refinement. Based on this effort, the Navy submitted its first satellite development proposal to the joint Army and Navy Aeronautical Board on 7 March 1946; a group established during WWII to coordinate R&D between the Army Air Corps and the Navy.
The Army Air Corps (soon to become the U.S. Air Force) was caught off guard by the Navy proposal, and the next meeting of the joint Aeronautic Board's R&D Committee was delayed until 14 May 1946 to give the Army Air Corps time to prepare a response. In a crash effort to develop "equal competence" with the Navy on satellites and thus avoid being excluded from future military space research, General Curtis Le May, then director of R&D for the Army Air Force, assigned Douglas Aircraft Company and its Project RAND Group to undertake a three-month study on the service's behalf. Given the constraints on time, RAND produced a remarkably comprehensive report, not only on the technical feasibility but also on the future utility of space vehicles.
While RAND prepared its assessment, the Commanding General of the Army Air Forces was informed of the Navy satellite development proposal, and in 1946 the Air Staff argued that
...Army Air Forces should have primary responsibility for any military satellite vehicle, considering such activity to be essentially an extension of strategic air power [3].
This position was to be reiterated by the Air Force many times over the next five decades.
At the May 1946 meeting of the Aeronautical Board's R&D Committee, no agreement was reached as to which proposal, Navy or Army Air Corps, should be approved. The Board also postponed the decision as to service responsibility for satellite development until it received higher-level guidance.
After serious exploration of concepts for putting a satellite in orbit, the Navy's committee for evaluating space rocketry folded in early 1948, succumbing primarily to post-World War II budget cuts.
In mid-1948, the Navy proposed to undertake a joint project with the Air Force to develop earth-orbiting satellites, a proposal that was rejected by the Air Force. The Navy abandoned further efforts to form a joint satellite program in late 1948.
Proposals for space-related activity continued to be developed by the Navy, Army and Air Force, but all such proposals were opposed by Vannevar Bush, head of the powerful joint Research and Development Board. (Bush also opposed development of rocket boosters for long range missiles.) In 1948, the Secretary of Defense reported, with respect to space [3]:
The (joint) Committee on Guided Missiles "recommended that efforts in the field (of earth satellite vehicles) be limited to studies"
Reshuffling of the military services as the consequence of the National Security Act of 1947 garnered most of the attention of the Services for the next few years, and space took a back seat.
1.3 Navy requirements for communications, navigation, and surveillance at the end of Korean War
During W.W.II and continuing through the Korean Conflict, Navy ship-to-shore long-haul communications relied on the medium and high frequency (MF and HF) portion of the radio frequency spectrum. Signals at these frequencies can travel great distances but are affected by meteorological conditions, solar activity, and time of day. Beginning in W WII, the Navy established an extensive network of shore-based communications facilities to provide reliable connectivity for the fleet in many areas of the world. At the end of the Korean Conflict, however, severe cuts in the Navy budget dictated the closure of many of these overseas communications stations. The Navy then faced the challenge of building a communications network that could support fleet operations that were expanding to literally global proportions because of Cold War responsibilities.
In a similar fashion, the Navy and Army Air Corps had created LORAN, LORAN C, and OMEGA shore navigation stations all over the world to support W WII and post-war navigation requirements for ships and long-range aircraft. The dramatic cuts in defense spending following the Korean Armistice and into the late 1950s forced the closing of many of these facilities at the same time the U.S. Navy was preparing to deploy submarines that carried nuclear missiles--submarines which needed to determine their own positions accurately if missiles were to hit targets more than 1,000 miles down range.
Finally, W.W.II had produced major increases in broad ocean surveillance capabilities in the U.S. Navy, including modern patrol aircraft and Blimps. Post Korean Conflict budget reductions and lack of a Soviet "blue water" threat forced reductions in the number of air surveillance resources at a time when Navy Cold War responsibilities were growing to global proportions.
1.4 Sputnik 1: The watershed event
1.4.1 The challenge of monitoring activities behind the Iron Curtain
The U.S. ended W.W.II as the most militarily powerful nation the world had ever known. In spite of massive demobilization at the end of the war, Americans remained supremely confident that the U.S. monopoly in nuclear weapons provided all the clout needed for the foreseeable future. The triple shocks of: the Soviet blockade of Berlin (1948-49); the Soviet detonation of a nuclear device (1949); and the conflict in Korea (1950-53) undermined U.S. confidence and generated urgent requirements for information on Soviet military capabilities.
The Soviet Union was, at that time, one of the most secretive and closed societies in the world. The U.S. tried a wide range of techniques for peering beyond the Iron Curtain, including:
The failure of these and other approaches to reconnaissance of the Soviet Union, led the Eisenhower Administration to consider satellite reconnaissance as an alternative. There was, however, concern about two political aspects of space-based reconnaissance: (a) how would the Soviets respond; and (b) would the rest of the world object to U.S. satellite surveillance?
The Eisenhower administration determined, therefore, to pursue space goals in two distinct parts: military and civilian. The civilian part would be overt, "scientific," highly advertised and fully exploited for its world propaganda value [4]. The military part would be covert and highly secret. (The high degree of secrecy was as much to avoid bad publicity abroad as it was to keep the Soviets from knowing the details.) The mere existence of U.S. spying and other sensitive military applications from space would not be acknowledged openly by the U.S. government.
This "military" versus "civilian" (called "scientific") dichotomy was rigorously implemented by the U.S. Government and was to rule U.S. space programs for ensuing decades. During the early 1960s, for example, either a U.S. space program was 'scientific", or it did not overtly exist. (Later in that decade, existence of several military space systems did become public knowledge, among them TRANSIT and the Defense Meteorological Satellite Program (DMSP), both highly successful, programs.)
The U.S. Navy engaged in both aspects of this 1960s space program, military and scientific. The Naval Research Laboratory developed a highly classified satellite reconnaissance system (See Section 2.5) and at the same time participated with the scientific community in unclassified space research (which served in some cases as a cover for the NRL's classified work). The Navy's Transit navigation satellite development at the Applied Physics Laboratory was an exception to the rule. Transit was developed and launched to provide precision navigation for Navy Fleet Ballistic Missile (Polaris) submarines. Initially a classified effort, the technical details of Transit were later released to the public to improve safety of navigation and similar uses.
1.4.2 First on orbit!
During the 1950s, Wernher von Braun aggressively lobbied the U.S. government to develop a satellite launch vehicle using components available from the Army Ordnance Corps. It would be an Army development, but von Braun believed it was essential to obtain the support of all three Services. The Navy responded favorably; the Air Force declined to participate. By the spring of 1955, the Army and Navy had worked out details for a joint satellite concept called "Project Orbiter." The Army began work on the project, but the Navy's participation was cut short by preparations for the 1957-58 International Geophysical Year.
1.4.2.1 The International Geophysical Year
In the early 1950s, a group of eminent international scientists proposed that the year 1957-58 should be dedicated to worldwide scientific endeavor, to be called the International Geophysical Year (IGY). The IGY Coordination Committee accepted a U.S. proposal to launch earth-orbiting satellites as part of the effort. The White House announced on 29 July 1955 that the U.S. would launch a satellite as part of 1957-58 IGY activities. The Soviet Union submitted a similar proposal at an IGY meeting hosted by the U.S. National Academy of Silences in June 1957.
Although the IGY satellite project was designed to be primarily a scientific enterprise, the services recognized that military benefits might accrue from participating. All three of the U.S. military services submitted IGY proposals for an earth-orbiting satellite. They were:
The Navy's proposal was selected because it was felt that NRL's Viking rocket would most likely be considered by the world to be "scientific," whereas the Army and Air Force proposals were based on ICBM technology. (It is also possible that the Army's proposal was rejected in part because its chief engineer was one-time Nazi weapon builder, Von Braun, a matter of concern barely ten years after W.W.II.) A final factor in the selection of the Navy's proposal was a desire not to interfere with Army and Air Force ICBM development.
The Naval Research Laboratory began briskly preparing for the launch of what was anticipated to be the world's first artificial earth-orbiting satellite as part of the 1957-58 International Geophysical Year. What was not fully appreciated (then or now) was the major technological leap forward envisioned for Vanguard. The technology was sound conceptually but could not be accelerated easily.
1.4.2.2 Sputnik!
In October 1957, the Soviet Union surprised the world by launching "Sputnik," the world's first artificial satellite. Despite the fact that the Soviets had announced it in advance, Sputnik's success shocked the American people greatly.
Sputnik evoked fast action on the part of the Eisenhower administration. On 7 November 1957, the President announced the appointment of a Special Assistant who would chair the Presidential Science Advisor Committee (PSAC). The next day, as a backup to Project Vanguard, the Army was authorized to proceed with its proposed satellite program using the Redstone missile (thereby abandoning the U.S. attempt to maintain that its participation in the IGY was purely non-military and lowering ICBM development to second priority).
The hedging of this bet was none to soon. The first NRL attempt to launch its Vanguard satellite, in December 1957, was a disastrous and embarrassing failure for the Navy and the nation. The rocket blew up on the launch pad. As a result, the decision was made to go to the Army Redstone program, producing the first successful U.S. satellite launch on 31 January 1958.
1.5 The new U.S. space organizations, 1958-1961
1.5.1 NASA
The Soviet Union never pressed the issue of violation of territorial integrity resulting from over-flight by a satellite. They were hardly in a position to do so given that Sputnik was first. Throughout the late 1950s, however, there were strong U.S. and international sentiments (encouraged by a major Soviet propaganda effort) that any U.S. use of space should be limited strictly to "peaceful" applications. This meant that in order to accommodate world opinion, and to avoid offending the Soviets, the United States would have to limit overt space programs to scientific applications; any development of space by the military would have to be done covertly. (The Soviet Union's worldwide propaganda effort, which attempted to limit U.S. space efforts to non-military applications, was a cover for the fact that the Soviets were working on satellite reconnaissance and other military space systems, and were simply trying to delay U.S. military space efforts in order to get a head start.)
As noted earlier, the Navy's Vanguard program involved major advances in rocket technology including gimbaled rocket motors, advanced fuel pumps, and innovative staging concepts-many of which were incorporated into NASA's man-rated Saturn rocket, the most reliable rocket built by the U.S. Vanguard did launch three payloads successfully for the IGY, including sensitive instruments that measured the Van Allen Bells and the first imaging system carried into orbit.
In early 1958, plans were made in the United States to establish a national space agency as a civilian scientific organization, providing an image of U.S. peaceful use of space. President Eisenhower was opposed to the creation of a civilian space agency separate from the Department of Defense as an unnecessary and costly duplication of effort, arguing that DOD could be the operational agent for all U.S. space programs. By March 1958, however, the President bowed to growing pressure to set up an independent, civilian organization for the non-military use of space. The National Aeronautics and Space Agency (NASA) was established by Congress on 2 April 1958. NASA's responsibilities and those of the Defense Department were differentiated as follows in the National Aeronautics and Space Act of 1958:
[All space activities] ...shall be the responsibility of, and shall be directed by a civilian agency (NASA), except that ... activities primarily associated with the development of weapons systems ... shall be the responsibility of, and shall be directed by, the Department of Defense.
Its merits notwithstanding, establishment of NASA as an organization separate from DOD resulted over the years in competition within the U.S. space program. The most important impact was on the U.S. Air Force, which eventually took over the DOD space-launch responsibilities, and competed with NASA for launch of U.S. military spacecraft. There was also a brief struggle between NASA and the Air Force over manned space flight (see Section: 2.6).
Staffing for the newly created NASA organization in 1958 drew heavily on the military services' base of space-qualified technical people. The Army was required to transfer Von Braun and several thousand members of its rocket team to NASA. The Air Force also had to provide NASA with much of its expertise to carry out the transition.
The Navy had to share with NASA an even higher proportion of its relatively small space technology base. More than 300 space scientists and technical personnel were transferred from the Naval Research Laboratory in 1958 to help fill NASA's billets. The NRL Vangarde group, a total of approximately 200 scientists and engineers, remained housed at NRL until the new facilities at the Goddard Space Flight Center at Beltsville, Maryland, became available in September 1960.
NASA's manning requirements were later to place another demand on the Navy, in another personnel area: Naval (Navy and Marine Corps) officers eventually provided more than half the astronauts for NASA manned space flight programs.
1.5.2 ARPA
The Eisenhower Administration's response to Sputnik was to expand and accelerate the military as well as the scientific side of the U.S. space program. One of the President's first concerns was to eliminate the competition among the Services for space funding by attempting to concentrate all the military space funding in a single agency. The Advanced Research Projects Agency (ARPA) was established for that purpose on 27 November 1957.
The military versus non-military coordination between ARPA and NASA did not work well, nor was ARPA ever able to establish a working relationship with the Air Force. The DOD Deputy Director for Research & Engineering, Dr. Herbert York, believed that the creation of ARPA, if anything, had increased the amount of service rivalry [3]. In September 1959, therefore, all of the space projects under ARPA's control were transferred back to the military services, and ARPA was left to conduct only advanced research.
1.5.3 CINCSPACE is proposed, 1958
In 1958 (while the role of ARPA in space development was being debated), the services discussed a proposal by the Chief of Naval Operations, Admiral Arleigh Burke, that a "unified space command" be created, to take ARPA's place. Ironically, in the light of developments in the 1970s and 80s, the idea was strongly opposed at that time by the Air Force, in the belief that this would jeopardize its campaign to take over the entire space mission [3].
1.5.4 The National Reconnaissance Office
1.5.4.1 Background
In the 1950s, the RAND Corporation recommended that the Air Force pursue research into satellite reconnaissance missions. These recommendations were pursued by the Air Force R&D command under the project name "Feedback." In March 1954, Project Feedback personnel recommended that the Air Force develop and operate a satellite reconnaissance vehicle as a matter of "vital strategic interest to the U.S." This project, which was to be conducted in strictest secrecy, was approved by OSD in May 1954 and was given the unclassified title "Advanced Reconnaissance System," designated WS-117L. The operational objective of WS-1 176, defined in Air Force General Operational Requirement No. 80, was to provide surveillance of "pre-selected areas of the earth" (in particular the land-mass of the USSR and any other area potentially denied to U.S. access for intelligence) in order "to determine the status of a potential enemy's war-making capability." The Executive Agent for Project Feedback was the Air Force R&D Command.
At the same time, the Central Intelligence Agency had also become interested in strategic reconnaissance for national intelligence, using high-flying aircraft, rather than satellites. The CIA was, for example, responsible for developing the U-2. In 1958, President Eisenhower directed the CIA to develop a reconnaissance satellite system. While this decision ran counter to his persistent desire to avoid duplication, the President's Board of Consultants on Foreign Intelligence in February 1958 reported that the Air Force's WS-117L Advanced Reconnaissance System would not be able to meet its near-term commitment, because it depended on the Atlas booster which was a long way from becoming operational. The Board recommended that the CIA develop reconnaissance satellites that could be launched from the existing Thor IRBM. The CIA project, known as "Corona," was funded largely by the CIA, and indirectly by the Air Forces' Discoverer program, which served as its "white world" cover.
Lockheed (the builder of the CIA's U-2) was selected as prime contractor for the Air Force WS-117L program. The company was also prime contractor for the CIA's "Corona."
The CIA imagery system differed from the Air Force system in one important way: the CIA system depended on jettison of film canisters from the satellite and recovery in mid-air, while the Air Force system depended on televising the satellite's photography.
By the summer of 1959, the U.S. satellite reconnaissance program was in a state of crisis. The CIA-managed Corona/Discoverer tests had not had a single success, and the Air Force-managed program (first called "Sentry", and later "Samos') was slipping at an enormous rate due to technical problems. Concern over this lack of progress led directly to the creation of the National Reconnaissance Office in August 1960.
1.5.4.2 Establishment of the NRO
So secret was the operation of the NRO that its very existence was only inadvertently revealed by the Senate in 1973. By 1968, the National Reconnaissance Program had branched into three developments:
1.5.5 The Defense Communications Agency (DCA)
In 1962 the Department of Defense experienced difficulty during development of a communications satellite called "Advent' (See Section 1.6.2). As a result, Secretary of Defense McNamara established the Defense Communications Agency (DCA).
The DCA was given the responsibility for centralizing all jointservice requirements, plans, and operations for communications (including satellite communications) for strategic and joint logistic applications. (Tactical communications remained a function of each military service.)
1.6 The Navy's space program burgeons, 1958-1961
The first efforts by the Navy to exploit space came in the late 1950s, when an ad hoc group chaired by the Deputy CNO for Air Warfare (OP-05) published a study, "Navy in the Space Age," which recommended a substantial increase in Navy space organizations. As a result, the CNO established within his headquarters the Astronautics Operations Division (OP-54) and the Space Research, Development, Test and Evaluation Division (OP-76). In the Bureau of Naval Weapons, an assistant director was appointed for the Pacific Missile Range and Astronautics.
1.6.1 Origins of the Transit Navigation System
In July 1957, APL established a space exploration study group, to look into ways of applying the Laboratory's technical expertise to the field of space research. Although this ad hoc study group never submitted any formal proposals, it did create an area of research interest and specialized knowledge within the Laboratory, so that "when an idea that was really good came up, they saw it." That one "really good" idea arose in the autumn of 1957, in the wake of the Soviet Union's launch of its Sputnik satellite on October 4.
The consternation Sputnik aroused at APL was tempered by the fascination that the Soviet achievement aroused in many members of the Laboratory who actually, in the words of one senior-level APL official, "thought it was pretty neat." One of those who was captivated by the Sputnik episode was William Guier, who had joined the Laboratory in 1951. Sputnik was launched on a weekend. "The next Monday I came in," remembered Guier, "and to my surprise, no one was listening to it. They kept saying you could get it on twenty megacycles, and I thought someone would be listening, with all the receivers all over this place. So in the early afternoon, I decided I'd see if I could get that thing."
Guier had been working recently in the Research Center with George Weiffenbach, a physicist who had joined APL at about the same time. As part of his experiments in microwave spectroscopy, Weiffenbach had been using a shortwave receiver that could pick up very sensitive radio signals. Around four o'clock that afternoon, Weiffenbach stuck a piece of wire into the antenna connection on his receiver, and he and Guier began listening to the distinctive "beep- beep" signals emanating from Sputnik. When Weiffenbach analyzed the tape recordings with the aid of a wave analyzer, the result was "an absolutely gorgeous Doppler shift." In other words, the satellite's signals sounded higher pitched as Sputnik came loser to Washington and lower as it went away, just as a bystander would hear the whistle of a freight train change pitch as the train approaches and passes.
While waiting for the satellite's next pass over the United States, Guier realized that the slope of the Doppler shift could help him ascertain the distance to Sputnik. To compute the satellite's path, he and Weiffenbach used the estimated time of Sputnik's arrival over Washington, as broadcast by a Moscow shortwave radio station that Weiffenbach had serendipitously picked up on his receiver. After listening and recording data for several days, the two physicists discovered they could use a mechanical calculator to predict the satellite's orbit much more accurately than could the elaborate tracking system employed by the Navy's research station in downtown Washington. Unfortunately, Sputnik I stopped sending signals after the first week because its storage batteries gave out. But Guier took his calculations and began processing them on the Laboratory's recently installed Univac 1103 digital computer.
When the Soviets launched Sputnik II on November 3, the signals from space resumed and Weiffenbach and Guier discovered that, with the aid of the Univac, they were able to carry out even more sophisticated experiments with their Doppler data. They still were tracking the satellite more accurately than anyone else in the nation; moreover, they were doing it from a single station, thereby defying the conventional wisdom that at least two stations were needed to track a spacecraft accurately.
For nearly six months, Guier and Weiffenbach and a small team of colleagues persisted in tracking first Sputnik II and then the first U.S. satellite, Explorer I, which was launched at the end of January 1958. Their superior, Frank McClure, then realized that if one can find a satellite from a listening station on earth using the Doppler-shift data, then one can find the listening station on earth from the orbit, and within a week he and an APL colleague had designed a navigation system on this principle [5]. The system would consist of four basic elements: (1) a satellite containing a highly precise crystal-driven dock or cycle counter, a frequency generator, and a dual-frequency radio transmitter to beam signals to earth; (2) a network of hacking stations to measure the frequency of the received satellite signals; (3) an injection station, or communication channel, to permit ground engineers to insert the predicted orbital positions of the satellite (which they calculated using the previous day's tracking data) into the spacecraft's memory every twelve hours; and of course, (4) the shipboard navigation set to receive and interpret the signals broadcast by the satellite. The proposed navigation system came to be known as Transit [5].
At the time Transit was first proposed, in the spring of 1958, the world had only five small, relatively simplistic, artificial satellites in orbit: the two Soviet Sputniks, the U.S. Army's Explorer, and two U.S. Navy Vanguards. Less than three years later, the Navy succeeded in developing and demonstrating, with the help of the Applied Physics Laboratory, a space-based navigation system. This was a remarkable accomplishment, that included the development of a satellite tracking system; all the ground-based calculation and support facilities; and the users' navigation terminals.
Obtaining funding for development of Transit was tricky because of the Eisenhower Administration's policy that only ARPA was authorized to develop military satellite systems. The Navy's approach to "leveraging" ARPA funds was both innovative and elegant.
The dynamic Chief of Naval Operations, Admiral Arleigh Burke, had created a Special Projects Office which was charged with developing both submarines and missiles for the Polaris program. One of the challenges faced by the Polaris program was the need for high targeting accuracy because of the relatively small nuclear warheads carried by the first missiles. One source of targeting error was the accuracy with which the submarine's position was known at the time of launch. The Polaris program developed sophisticated Ships Inertial Navigation Systems (SINS) and periscope star trackers to provide more accurate own-ship position, but these systems still drifted and star fixes could not be updated in poor weather. [Note: Concern about the accuracy of Polaris missiles reached the highest levels in 1957, when President Eisenhower personally challenged Admiral Burke to address this problem. ("The History of the U.S. Navy" (Vol II) 1942-1991" , by Robert W Love, Jr., Stackpole Books, Harrisburg, PA.)]
The theoretical accuracy of a Transit satellite navigation system and its potential for all-weather, global support met a high priority operational requirement of the Polaris program. The Polaris program office used this argument successfully when it prevailed upon ARPA to fund the development of the Navy Transit program.
Transit was the first military satellite system built and operated in response to specific operational requirements and serves as an excellent example of the Navy's philosophy of applying space systems to solving specific problems "on the ground."
Probably the most vexing difficulty with the Transit program arose when the APL Transit team confirmed that the shape of the earth, especially the northern hemisphere, was far less regular than believed previously. This revelation had critical implications for the accuracy of the proposed navigation system. It became obvious that, because the Earth's gravitational field was much more complex than was thought, one needed tracking stations pretty much all over the world to get the best out of the satellite navigation system. The satellite was moving in an orbit, but a much more complex orbit than early theory had indicated.
To learn more about this "gravitational error" phenomenon, the Transit group instituted an intense geodetic research effort, with computer programs that took weeks to write and eighteen hours to run. Soon the Laboratory's geodesy program had grown into a significant research and satellite-building operation of its own, continuing for well over a decade.
While the first experimental Transit satellite was being constructed at APL, the Laboratory also designed and built Transit tracking stations and transported them to four locations: Austin, Texas; Seattle, Washington; Las Cruces, New Mexico; and Argentia, Newfoundland. A fifth tracking station was located at the APL facility in Howard County, Maryland. In addition, the British government built and erected its own station at the Royal Aircraft Establishment in Farnborough, Hampshire. All these stations were connected by telephone and telegraph to the Transit Control Center in Howard County, Maryland, as were the Atlantic Missile Range at Cape Canaveral, and the APL Computing Center.
On Friday, September 17, 1959 - barely nine months after the Laboratory received the initial Transit funds from ARPA- the first APL satellite, known as Transit lA, was ready for launch from Cape Canaveral. (The 130-pound satellite had been shipped in a plain wooden box from the Laboratory to the cape by truck, with little publicity.) All the components had been so thoroughly tested ahead of time that few among the Transit team had any doubt the satellite would operate as designed; instead, they were far more concerned about how long it would last in the uncertain environment of outer space.
Two minutes after lift-off, APL observers learned that the Howard County station was locked onto two frequencies from the satellite as it sped across the Atlantic, rising to an altitude of approximately two hundred miles. Shortly thereafter, the tracking station at Argentia reported that it too was receiving signals from the satellite. Using these signals, technicians at APL determined the Doppler frequency shift and plotted the data on large charts. For the first eleven minutes, the frequency shifts exactly matched the theoretical curves that had been calculated weeks in advance. But then, where there should have been a break in the curve signaling an acceleration from the ignition of the third stage of the rocket, the curve simply continued to follow a smooth course. Meanwhile, the Farnborough station reported that dear signals had been received from the satellite for several minutes and then suddenly died away.
By this time, it had become clear to the Transit observation team at APL that the third stage of the rocket had failed to ignite, sending the satellite plunging into the sea. But in those first brief minutes of radio contact, the spacecraft had demonstrated that the electronic gear had withstood the shock, vibration, and acceleration of launch. Perhaps more significantly, the brief event proved that ground stations could use the satellite's signals to plot its orbit.
On January 1, 1960, the Applied Physics Laboratory officially established its Space Development Division. On April 13, the second Transit satellite (Transit 1B) was launched from Cape Canaveral. Again the Transit tracking stations heard the signals as the satellite soared skyward; this time the spacecraft made it into orbit safely.
The satellites designed and launched during the experimental development phase of the Transit program, are summarized in table 1. Each satellite was progressively more sophisticated and tested one or more new elements of the technology that would be needed in an operational system.
All of these experimental Transit satellites were launched on the Air Force's new Thor-Able-Star launch vehicle, one of the earliest examples of inter-service cooperation in space. Only Transits 4A and 4B were launched perfectly. Transits 1B, 2A, and 3B went into orbit at uncomfortably low altitudes. (The launch of these experimental Transit satellites, it was said, served as much to "debug" the Thor-AbleStar launch vehicle as they did to demonstrate the Transit system [6].) Each of these experimental Transit satellite-even Transits 1A and 3A which went into ballistic trajectories provided useful data, however.
The Transit 4A launch was interesting in that it was part of a triple payload; the other two satellites were a scientific satellite (INJUN) designed by Dr. James Van Allen, and an NRL satellite that is discussed in a later chapter. Even though it was not intended to be an operational navigation satellite, Transit 4A provided navigation data used for calculating the accurate positions of ships at sea (in post-operation or post-exercise reconstruction, rather than in real time, however). Transit 4B, like Transit 3B, had a nuclear (radioisotope) power supply.
Table 1. Experimental and pre-production Transit satellites
| Mission number | Launch date | Status | Comments |
| 1A | 17-Sep-1959 | Failed to orbit | |
| 1B | 13-Apr-1960 | Navigation & tracking experiments | |
| 2A | 22-Jun-1960 | Navigation & tracking experiments | |
| 3A | 30-Nov-1960 | Failed to orbit | |
| 3B | 21-Feb-1967 | Navigation & tracking experiments | |
| 4A | 29-Jun-1967 | Fleet navigation trials | |
| 4B | 15-Nov-1961 | Fleet navigation trials | |
| 5A1 | 19-Dec-1962 | Failed 20 hours after launch | |
| 5A2 | 5-Apr-1963 | ||
| 5A3 | 16-Jun-1963 | Memory problems in orbit: never operational | |
| 5BN-1 | 28-Jun-1963 | Prototype with nuclear power source | |
| 5BN-2 | 5-Dec-1963 | Operational; satellite with nuclear power source | |
| 5BN-3 | 21-Apr-1964 | Failed to orbit | |
| 5C1 | 4-Jun-1964 | Prototype with solar power only | |
| O-4 | 24-Jun-1965 | Operational Prototype | |
| O-6 | 22-Dec-1965 | Operational Prototype | |
| O-8 | 25-Mar-1966 | Operational Prototype | |
| O-9 | 19-May-1966 | Operational Prototype | |
| O-10 | 18-Aug-1966 | Operational Prototype | |
| O-12 | 14-Apr-1967 | Operational Prototype | |
| O-13 | 18-May-1967 | Operational Prototype | |
| O-14 | 25-Sep-1967 | Operational Prototype | |
| TRIAD/TIP-I | 2-Sep-1972 | Transit improvement program (TIP) (failed 60 days after launch) | |
| TIP-II | 12-Oct-1975 | Never operational; solar panel problems | |
| TIP-III | 1-Sep-1976 | Never operational; solar panel problems | |
| O-11/ TRANSAT | 28-Oct-1977 | Operational prototype and beacon for range calibration | |
| Notes: | |||
| (1) All of the experimental and prototype Transit satellites listed above were built for the Navy by the Johns Hopkins University - Applied Physics Laboratory | |||
| (2) Production Transit satellites were called Nova and were built by RCA Astro-Electronics under a Navy contract. The first Nova satellite was launched 15 May 1981. | |||
1.6.2 Navy's satellite communications, 1958-61
1.6.2.1 Communication Moon Relay, the world's first operational "communications satellite" system
The first operational military satellite communications system, the Communications Moon Relay (CMR) [an earth-moon-earth link that connected Washington, D.C. and Hawaii,] was authorized by the Chief of Naval Operations in 1956.
The inaugural test of CMR was conducted in January 1960 when CNO (Adm Arleigh Burke) sent a teletype message to the Commander-in-Chief, Pacific Fleet (Adm Herbert G. Hopwood). The teletype message was followed by two facsimile images: the first (in those politically incorrect times), a photo of a "moon maiden," of the centerfold variety, the second, a more appropriate public affairs photograph (see figure 5).
A CMR receiver and 16-foot steerable parabolic dish antenna were installed in USS Oxford (AG159) in 1961. The Naval Research Laboratory demonstrated the first shore-to-ship satellite communications relay on 15 December 1961 when ceremonial messages were sent by the Chief of Naval Operations (Adm G.W. Anderson) to USS Oxford from NRL's Stump Neck, Maryland satellite research facility (see figure 6). The first two-way ship-to-shore satellite communications was conducted when USS Oxford was at sea between Buenos Aires and Rio de Janeiro on 30 March 1962.
The Navy's CMR system carried operational message traffic between Hawaii and Washington DC for half a decade. The ground stations were manned by Navy personnel from four to eight hours daily (that is, from moonrise in Hawaii to moonset in Maryland) [2].
CMR was the only operational satellite communications relay system in the world until the Defense Satellite Communications System came on line 16 June 1966.
The CMR system offered very reliable communications, and was resistant to jamming. Curiously, the National Security Agency and the Naval Security Group did not allow encrypted message traffic on the CMR link, arguing that anyone could intercept the link because "all the world could hear it"- despite the fact that encrypted messages had been transmitted on the MF/HF broadcasts for years [1]. The principal limitation of the CMR was simply the availability of the moon, which had to be within sight of both of the link terminals. As observed by then- LCDR Edelson at the Bureau of Ships, this was only a single-satellite system, and for reliable 24-hour communications the Navy would need a constellation of multiple (artificial) satellites.
The CMR capability was disestablished in the mid-1960s and its antennas were used in the Technical Research Ship Special Communications (TRSSCOM) System.
1.6.2.2 Passive satellite communications relay ("Echo")
During the late 1950s the Natal Research Laboratory undertook a joint project with NASA, the Jet Propulsion Laboratory (JPL), and the Bell Laboratories of AT&T to conduct radio-communications relay tests using passively-reflecting, artificial satellites.
NASA provided the Echo-I satellite, a self-inflating 100-foot diameter aluminum-coated plastic sphere, the surface of which was half the thickness of cellophane wrappings on a package of cigarettes. The Navy's CMR ground facilities were combined with a JPL station in California and a Bell Telephone station in New Jersey to form a ground network.
Echo-I was launched into an orbit a thousand miles above the earth by a Thor-Delta rocket from Cape Canaveral on 12 August 1960. Within three days, NRL scientists and technicians had bounced voice and other messages off the passively reflecting satellite and established communications with the other stations. Many other radio and optical tests were made by cooperating stations in the U.S. and overseas. Tests with the Echo satellite proved the feasibility of longhaul communications via electronically passive (unamplified) artificial satellites and demonstrated the effectiveness of various coding and modulation schemes.
At the request of the U.S. Post Office Department, NRL transmitted "space-mail" in the form of a facsimile letter for the first time over a man-made satellite communication circuit on 10 November 1960. A special stamp was issued by the Department in commemoration (see figure 7).
1.6.2.3 Active satellite communications relay ("Score," "Courier" and "Advent")
In 1957, shortly before the first Sputnik was launched, the Naval Research Laboratory proposed to the Navy Department an R&D program on communications satellites with active transponders, to supplement the passive communications work using the moon and artificial satellites like Echo which was in progress at that time. In 1959, this proposal was expanded to include equipping a ship for satellite communication experiments. This proposal was adopted by the Navy, and issued by the Chief of Naval Operations as the Navy "Satellite Communication Plan," which was sent to the Secretary of Defense for formal approval. The Navy proposal was turned down, however, because of the White House policy that only ARPA could fund military satellite developments.
The first U.S. military communications satellite was "Score," a 130-pound payload built in just a few months by DOD. Score was built into the side of an Atlas rocket and was launched in December 1958. Score was a "store-and-forward" system that recorded messages received over one area of the earth and rebroadcast them over a different area. Score transmitted President Eisenhower's 1958 Christmas message to the world which became known as the first "voice from space." Score's 8-watt VHF transmitter was powered by unrechargeable batteries and died on New Year's Eve.
The second DOD satellite communications experiment was Courier. Courier was a true satellite, of the store-and-forward variety, and was designed as a technological stepping stone to an operational satellite communications system. The Courier satellite was 130 centimeters in diameter and weighed 500 pounds. The satellite incorporated: solar cells; Four receivers; four transmitters; five tape recorders; and was capable of relaying both voice and digital data at several kilobits per second. Courier was launched in October 1960, on an Air Force Thor-Able-Star rocket, into a 600 n.mi. orbit. An on-board system fault shut the satellite down after only 18 days of operation, providing scientists and engineers an early demonstration of the perils of complexity in orbiting systems.
In 1959, the Department of Defense authorized development of the first operational satellite communications system, called "Advent." Advent was to serve as an active communications relay for all the military services. The program called for developing three one ton, stabilized, high-powered, microwave satellites and plating them in geosynchronous orbit in two years.
The management organization for Advent was complex. ARPA was to provide overall direction. The Air Force was responsible for building the spacecraft. The U.S. Army (Signal Corps) was responsible for designing the communications repeater in the spacecraft. The Air Force was to provide the first stage booster (Atlas), and NASA, the second-stage booster (Centaur). The Army was responsible for all the ground terminals, and the Navy, in accordance with its earlier proposals, was responsible for the shipboard terminals.
The Advent program was an abysmal failure, and was canceled in 1962 after the expenditure of $170 million. The failure was blamed on many things, including the setting of requirements beyond the technological capability to meet them. But the fundamental reason for the failure was the impossible management structure.
The Navy did accomplish its part of the project, by converting a ship USNS Kingsport into an ocean-going terminal for the Advent system. The Kingsport came out of the shipyard in 1962, just in time for program cancellation. The Kingsport turned out to be a useful output of the Advent project, however, as it became the research ship used for many important communications experiments with DOD and commercial satellites later in the 1960s. (See Section 2.3.2)
Table 1. Initial eight ground sites selected by the joint committee
| Location | Operated by |
| Bremen, Germany Todendorf, Germany | U.S. Navy U.S. Navy |
| Istanbul, Turkey | U.S. Navy |
| Base of the Caspian Sea, Iran | CIA |
| Peshawar. Pakistan | U.S. Air Force |
| San Mogul, Philippines | U.S. Navy |
| Sakate, Japan | U.S. Navy |
| Shemya, Aleutians | U.S. Army, Navy and Air Force |
1960 was one of the grimmer years of the Cold War in so far as reconnaissance is concerned. In May 1960, the Soviet Union brought an end to 4 years of overflights by U.S. U-2 aircraft when Gary Powers was shot down. On 27 June 1960, the Soviets shot down a U.S. RB-47 SIGINT aircraft over international waters of the Barents Sea. In this climate, the White House demanded tight control over all reconnaissance assets.
1.6.4 Navy environmental satellites
Not long after the launch of the first Sputnik, it was recognized that satellites could provide excellent platforms for observing the sun and monitoring radiation that affects naval communications. The Naval Research Laboratory was quick to take advantage of this potential. The fast SOLRAD satellite was developed, launched, and in use to monitor solar radiations by June 1960, only two years after Sputnik.
In 1958 there was also much interest by scientists and military planners in using satellites to measure the radiation and other effects of nuclear detonations in space. This information was wanted by those who were investigating ways to disable enemy satellites, as well as by those who wanted to protect U.S. satellites. Some satellites inadvertently provided the desired information when they became unintended victims of nuclear detonations in space.
1.6.5 Navy spacecraft detection and tracking systems
During the early years of the U.S. space program, the principal satellite-tracking systems were those of the U.S. Navy. This was not the result of any deliberate Navy planning to undertake such a mission, but the result of efforts to monitor the down-range trajectories and subsequent orbits of Navy Vanguard and Transit satellites.
1.6.5.1 APL's Tranet System
To support the development of the Transit navigation system, and its associated geodetic-research program, the Applied Physics Laboratory built a worldwide network of satellite tracking stations, (called Tranet) for the Navy. This system tracked Navy satellites and determined their positions accurately using signals transmitted by the satellites. During the early 1960s, Tranet had seventeen stations.
Table 2. Locations of the seventeen Tranet stations
| Station number | Location |
| 003 | Las Cruces, New Mexico |
| 006 | Lasham, Englanda |
| 008 | San Jose'dos Campos, Brazil |
| 011 | San Miguel, Philippines |
| 012 | Smithfield, Australia |
| 013 | Misawa, Japan |
| 014 | Anchorage, Alaska |
| 017 | Tafuna, Samoa |
| 018 | Thule, Greenland |
| 019 | Antarctica |
| 092 | Austin, Texas |
| *100 | Wahiawa, Hawaii |
| 111 | APL, Howard County, Maryland |
| 115 | Pretoria, South Africa |
| *200 | Point Mugu, California |
| *300 | Minneapolis, Minnesota |
| *400 | Winter Harbor, Maineb |
| (The asterisked (*) stations became the tracking stations for the Transit navigation system when it became operational. The other stations eventually became part of a system operated by the Defense Mapping Agency.) | |
a. This station was not operated by APL, but was built and operated by the Royal Aircraft Establishment at Farnborough.
b. Moved from its original location in Newfoundland.
1.6.5.2 NRL's Minitrack
The Minitrack system, which was developed under the supervision of Mr. Roger L. Easton at NRL, became operational in 1957 as part of the Vanguard program. Signals transmitted by the Vanguard satellites were collected at down-range stations arid were transmitted to the Vanguard Control Center at NRL. The ground segment of this system comprised a chain of down-range stations, each with a "fence" of common antenna beams, that extended from Blossom Point, Maryland, to Santiago, Chile. Additional Minitrack stations were located in Australia, South Africa, and San Diego, California. The Navy turned over operation of the Minitrack system to NASA, as part of the Vanguard program, in 1958.
1.6.5.8 The U.S. Naval Space Surveillance System (NAVSPASUR)
As early as 1958, some scientists and engineers recognized that the United States would need to be able to track large numbers of earth-orbiting satellites, its own and those launched by other nations. Knowledge of the presence, positions, and identity of objects in orbit would be necessary both for controlling U.S. satellites and detecting potential threats to national security.
Most of these satellites and related space "junk" did not provide cooperative emissions to aid in their identification. Similarly, tracking systems such as NRL's Minitrack or APL's Tranet, which depended on signals received from the spacecraft, would not suffice. For this reason, the Navy developed the world's first system for detecting and tracking non-emitting space objects.
This system, built by NRL, consisted of: (a) a ground-based 50 kilowatt, continuous-wave transmitter at Fort Monmouth, New Jersey, (provided by the Army Signal Corps Engineering Laboratories) to bounce signals off the orbiting objects; and (b) NRL's Vanguard Minitrack tracking station at Blossom Point, Maryland to receive them. A Russian Sputnik satellite (1957 Beta) was the first satellite tracked with this system.
On 29 June 1958, following a successful demonstration of this experimental system, ARPA asked the Navy to develop a U.S. space surveillance system to detect, identify; and track earth-orbiting satellite's and other orbital objects. The system, built by NRL and still in operation today, consists of three transmitter and six receiver sites placed from Georgia to California [at a latitude of 33.5 degrees north].
Table 3. U.S. Space Surveillance System
| Transmitter (location) | Receiver (locations |
| Jordan Lake, Alabama | Fort Stewart, Georgia Hawkinsville, Georgia |
| Kickapoo Lake, Texas | Silver Lake, Mississippi Red River, Arkansas |
| Gila River, Arizona | Elephant Butte, New Mexico San Diego, California |
This system provides a "fence" through which all lower-orbiting objects must pass at least once per day. The sites have antennas varying from 1,000-10,000 feet in length and transmitters with power ranging from 50-kilowatts to 1.0 megawatt [9]. In operation, the transmitters of the Space Surveillance System illuminate objects in space, the reflected radio-frequency signals are detected at receiving sites and are processed using a technique called radio-interferometry. The data from the receiving stations are then transferred via land line to the control system at Dahlgren, Virginia. The first two stations of the Space Surveillance System were put in operation on 29 July 1958, less than six weeks after NRL was tasked to build the system. The final station was completed in June 1961 [9].
The Space Surveillance System, designated WS-434, was operated by the Naval Research Laboratory until the Secretary of the Navy established the U.S. Naval Space Surveillance Facility (NAVSPASUR) at Dahlgren, Virginia, on 19 April 1960 to take responsibility for operating the system. NAVSPASUR was subordinated to the Naval Space Command in 1983.
The Space Surveillance System typically makes several hundred thousand observations per month, on about two thousand detectable earth-orbiting objects. Of these, about one-third are satellite payloads and the remainder are last-stage rockets and other space clutter. The data from the Space Surveillance System (WS-434) provide an important input to the Air Force's Space Detection and Tracking System (SPADATS). Ephemeris and other data computed by NAVSPASUR on satellites of military interest (e.g., Russian reconnaissance satellite's) are sent directly to the operating forces of the U.S. Navy and other services. Technical data for international scientific satellites are provided, via NRL, to the worldwide scientific community. Figures 9, 10, and 11 depict different elements of the U.S. Space Surveillance System.