Vanguard 1: The Little Satellite That Could

One of the more enduring images of the opening months of the Space Age was the failure of the Vanguard TV-3 launch attempt on December 6, 1957. Following three successful test flights where various stages and other hardware were tested in a step-wise fashion, the purpose of the TV-3 missions was to fly all three stages of the Vanguard launch vehicle for the first time in order to verify performance predictions with the remote chance that its payload would reach orbit. Unfortunately, the press overbilled the purpose of this test as the American response to Sputnik raising expectations for this flight (for a full discussion of the origin of the Vanguard program and the first test flights, see “Vanguard TV-3: America’s First Satellite Launch Attempt”). In response to this growing public relations disaster, the Eisenhower administration approved plans by a team led by Wernher von Braun at the Army Ballistic Missile Agency (ABMA) to launch a satellite as Vanguard program officials continued preparations for yet another test flight (see “Explorer 1: America’s First Satellite”).

The disastrous launch attempt of Vanguard TV-3 on December 6, 1957. (NASA)

Recovering from Disaster

After the disastrous failure of the Vanguard TV-3 launch attempt, Vanguard’s NRL (Naval Research Laboratory) team had to pick up the pieces and get ready for the launch of TV-3BU (Test Vehicle-3 Back Up). The contractor for the first stage, the Martin Company (one of the corporate antecedents of the aerospace giant, Lockheed-Martin), and the builder of the engine, General Electric, were able to track down the cause of the TV-3 failure to a loose fuel line connection. This loose connection caused a pressure drop in the GE X-405 engine’s fuel injector assembly which allowed combustion products to travel up the fuel lines resulting in a catastrophic failure. Modifications were immediately made to TV-3BU and its processing procedures to avoid a repeat of this incident.

Diagram showing the major components of the Vanguard “minimum satellite” used in the initial test flights of the program. (NASA)

Work to repair the damage caused by the TV-3 explosion at Launch Complex 18A on Cape Canaveral proceeded quickly and was completed ahead of schedule. This allowed TV-3BU to be erected on the launch pad before the end of December of 1957 for the start of its long prelaunch checkout. Like TV-3 before it, this launch vehicle would not carry an “operational” Vanguard satellite (see “Vintage Micro: The First Standardized Microsatellite”). Instead it would loft a simple test satellite. This “minimum satellite” was a 16 centimeter in diameter polished aluminum alloy sphere with a mass of only 1.47 kilograms – a “nanosatellite” by today’s definition. It was equipped with a pair of transmitters operating at a frequency of about 108 MHz that used six short aerials sticking out of the tiny sphere. One of these transmitters was powered by mercury batteries and would last just a few months. The other transmitter made use of solar cells mounted on the exterior for power as part of a test to determine their usefulness on future spacecraft. These solar cells were divided among six banks set equidistant around the satellite’s spherical exterior so that they could provide power regardless of the satellite’s orientation.

An engineering model of Vanguard 1 with its internal components displayed. (NRL)

The only actual instruments carried by the satellite were a pair of thermistors to measure the tiny satellite’s temperature. These measurements would help assess the sphere’s passive thermal control measures. The primary purpose of this payload, in addition to verifying that it went into orbit, was to provide an opportunity to exercise the Vanguard tracking network. As a byproduct, data on the evolution of the satellite’s orbit would provide some scientifically useful information about the upper atmosphere and the shape of the Earth (see “Vintage Micro: The Original Nanosatellite”).

The first attempt to launch the rocket on January 23, 1958 was called off when heavy rains shorted out some of the cables used by ground instrumentation. The next three days saw three more scrubs caused by a variety of problems. When it was discovered on January 26 that the second stage’s AJ10-37 engine was damaged, the launch of TV-3BU was pushed back to February 3 so that a replacement engine could be ordered and installed. Since the Cape Canaveral test range could only support one launch at a time, this delay gave the ABMA team led by Wernher von Braun a brief three-day window to squeeze in a launch attempt with their Juno I launch vehicle. The ABMA attempt succeeded in placing America’s first satellite into orbit on the night of January 31, 1958 as envious Vanguard personnel watched. The team that was suppose to orbit America’s IGY (International Geophysical Year) satellite would have to be content to take second place to their Army colleagues.

The delay in launching Vanguard TV-3BU gave von Braun’s ABMA team their chance to launch the first American satellite, Explorer 1, on January 31, 1958. (MSFC/NASA)

As it turned out, the new February 3, 1958 launch date proved to be a bit optimistic and it was not until February 5 before TV-3BU was finally ready to fly. When TV-3BU lifted off at 2:33 AM EST, all seemed to be going well at first. But at an altitude of 460 meters the rapidly accelerating rocket’s control system malfunctioned. Spurious electrical signals from the balky system caused the ascending rocket to rapidly pitch down. The structural loads this maneuver caused were more than the pencil-thin TV-3BU could take and it broke in two at the aft end of the second stage after 57 seconds of flight. Vanguard’s second attempt to launch a satellite had ended in failure. This setback, along with the launch failure of ABMA’s Explorer 2 one month later, was quite disheartening to the Vanguard team. They felt that if the tried and true Redstone-based Juno I could succumb to failure, how could the far more complex Vanguard succeed?

The launch of Vanguard TV-3BU on February 5, 1958.

Success at Last

After the TV-3BU failure, TV-4 was subsequently modified and prepared for another attempt to launch a grapefruit-sized test satellite. All during early March of 1958 the launch team had to wrestle with repeated electrical and mechanical problems as well as intermittent bad weather. After three scrubbed launch attempts, the Vanguard team started yet another two-day long countdown on March 16, 1958 in the hope of getting their bird off the ground.

The Vanguard “minimum satellite” shown mounted atop the third stage of its launch vehicle before being enclosed by its nose cone. (NASA)

As before, there were a series of minor delays in the countdown. At 6:50 AM EST on March 17, there was yet another unscheduled hold in the countdown called this time to allow the passage of Explorer 1 overhead. Engineers wanted to avoid the Space Age’s first “traffic jam” because the ABMA satellite’s transmissions might interfere with the reception of Vanguard’s signal. Finally at 7:15:41 AM EST, TV-4 lifted off and climbed into the sunny Florida sky. Telemetry streaming back to the Vanguard tracking stations showed that the first stage operated as intended. A near perfect performance by the second then the third stage followed. There was now every reason to believe that the test satellite had succeeded in reaching orbit.

The successful launch of Vanguard 1 on March 17, 1958 from LC-18A at Cape Canaveral. (NASA)

Confirmation that Vanguard had achieved orbit finally came around 9:30 AM EST when the Minitrack station in San Diego, California picked up signals from both of the small satellite’s transmitters. Vanguard 1 had made it into a 650 by 3,968 kilometer orbit with a period of 107.9 minutes inclined 34.3° to the equator. Initial calculations estimated that the satellite would remain in orbit until around the year 4000 AD. And with a mass of just 1.47 kilograms, Vanguard 1 would be the smallest satellite until the first 0.7-kilogram USAF Tedrahedral Research Satellites were deployed in orbit in 1963 (see “Vintage Micro: The Original Picosatellite“).

This diagram shows the ascent trajectory of an orbital Vanguard mission with the various downrange tracking stations indicated. Click on image to enlarge. (NRL)

With this launch, the Vanguard program had finally succeeded in meeting its commitment of launching one satellite during the IGY two years, six months and eight days after receiving authorization. Any successes after this would be a welcomed bonus. Even though they were not the first in orbit, the Vanguard team’s success was nonetheless an impressive engineering achievement. While the Soviet Sputnik and ABMA Explorer satellites had made use of military rockets adapted to the task of launching a satellite, the launch of Vanguard 1 marked the first time where a satellite was launched into orbit with a high performance rocket specifically designed for the task.

As Soviet authorities and even some in the West scoffed at the diminutive size of Vanguard 1 and its lack of sophisticated instrumentation, it proved to be a very useful tool. The battery-powered transmitter continued to operate until its mercury cells were exhausted in June of 1958. But the tiny satellite’s solar cell-powered transmitter continued to operate until May 1964. After this optical tracking allowed scientists to track the changes in its orbit. These changes and their causes provided much valuable scientific data.

An illustration of the variations in the geoid from a simple oblate spheroid derived from early satellite observations. (NASA)

First it was noticed how the minute force caused by sunlight reflecting off the little satellite perturbed its orbit. This combined with atmospheric drag whose magnitude waxed and waned noticeably with the level solar activity decreased estimates of Vanguard’s orbital life from 2,000 to only 240 years. Other perturbations in the orbit lead to a more refined estimate of the Earth’s oblateness. It was also discovered that the Earth’s geoid was distorted by a few meters into a pear shape with the pointed end at the north pole and the flattened end towards the south. These measurements indicated that there was large scale convection taking place inside the Earth which supported the then-new theories of continental drift and seafloor spreading. Although they had publicly avoided involvement in orbiting satellite before, the Department of Defense, whose military branches were quickly becoming interested in accurately lobbing nuclear warheads over intercontinental distances, took note of these discoveries.

Moving Towards Operational Launches

With the successful launch of Vanguard 1, its backup launch vehicle, TV-4BU was returned to the Martin Company’s Maryland facility for removal of test instrumentation and upgrades to critical systems so that the rocket could be used later in the program. The final test flight, TV-5, would attempt to launch the first “operational” Vanguard satellite. This standardized payload was a 51 centimeter in diameter lightweight magnesium alloy sphere with a mass of 9.8 kilograms – right on the low end of what is considered a “microsatellite” today. Unlike the simple Vanguard 1, the standard satellite of the Vanguard program was designed to carry one of five different instrument packages. For the TV-5 launch, the Vanguard satellite carried “Package Ia” which consisted of detectors to measure solar X-rays emissions in the 0.1 to 0.8 nm wavelength range (equivalent to an energy range of 1.6 to 12 keV) in addition to the “environmental sensors” to monitor the internal temperature and pressure of the satellite.

A diagram of the Vanguard “standard satellite” as shown in US Patent No. 2,835,548. (USPTO)

The first stage of TV-5 was erected on the launch pad during the first week of April 1958. The attachment of the upper stages had to wait for some time as problems with hydraulic disconnects identified in the film footage of the Vanguard 1 launch were addressed. These problems were quickly resolved and the last Vanguard test vehicle smoothly lifted off at 9:53 AM EST on April 28, 1958. While the first stage operated perfectly, the second stage firing sequence failed to complete itself electrically. As a result, the third stage was never armed and subsequently did not fire to place the payload in orbit.

The first “standard satellite” payload on Vanguard TV-5 being prepared for launch. (NASA)

With the completion of Vanguard’s test flight, flights with production rockets could commenced. First up was SLV-1 (Satellite Launch Vehicle-1). The satellite carried on this mission was identical to that on TV-5 except for its instrument payload. For this flight, Package I was carried which consisted of a detector to measure solar Lyman-α emissions in the 110 to 130 nm range of the ultraviolet and sensors to continue satellite environmental studies. Launched on May 27, 1958, SLV-1 operated perfectly until the second stage shutdown. At that time some sort of disturbance caused a loss of the attitude data from the control system’s pitch gyro. As a result of the malfunction, the third stage was pointing 63° off course when it fired and the payload failed to reach orbit.

Diagram showing the internal arrangement of equipment of the standard Vanguard satellite carrying the “Package I” instrument suite. Click on image to enlarge. (NASA)

On June 26, 1958 SLV-2 lifted off with a satellite payload identical to that carried by the ill-fated TV-5 launch vehicle. But this flight would fare no better than the last two. A restriction in the second stage’s oxidizer feed system caused its AJ10-37 engine to cease firing after a burn of only 8 seconds. This premature shutdown in turn caused the stage’s propellant tanks to overpressurize. While the payload never made it into orbit, the fact that the second stage withstood the excess pressure verified the structural integrity of the tank design under adverse flight conditions.

The launch of Vanguard SLV-2 on June 26, 1958. (USAF)

The flight of SLV-3, launched on September 26, 1958, was to carry a 10.6 kilogram satellite into orbit. This satellite was equipped with Package II consisting of a set of simple infrared photocells that would use the spinning motion of the spherical satellite to scan crude images of the Earth’s cloud cover. A tape recorder was also carried so that data could be stored for later transmission to the ground. Unfortunately this flight also proved to be unsuccessful. This time the problem was traced to contamination in the second stage fuel system which reduced its performance. By the time the third stage had burned out, the payload was traveling only 76 meters per second too slow to achieve orbit. The would-be satellite reached a peak altitude of 426 kilometers before it arced back towards the Earth and burned up on reentry about 15,000 kilometers downrange.

SLV-3 on the pad at LC-18A before its launch on September 26, 1958.

With these latest failures, Martin’s Corrective Action Team had their work cut out for them. While these flights failed to place their payloads into orbit, they were successful from the engineering point of view. Without exception, every flight returned plenty of good telemetry which in addition to other data, such as tracking photography, allowed the engineers to pin down the source of the problem and correct it on subsequent flights. But while Vanguard launches were suspended for a few months to allow modifications to be made to the remaining Vanguard launch vehicles, changes in the political climate were overtaking the Vanguard program and the rest of the America’s space projects. With the formation of NASA on October 1, 1958 as the sole civilian space agency, most space science programs run by the military as well as the Vanguard project were passed to the new organization. While the NRL was still responsible for the management of the Vanguard program, NASA now would be running the show (see “Vanguard 2: NASA’s First Successful Satellite Launch“).

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Related Videos

Here is newsreel footage for the successful launch of Vanguard 1:

Related Reading

“Vanguard TV-3: America’s First Satellite Launch Attempt”, Drew Ex Machina, December 6, 2017 [Post]

“Vintage Micro: The First Standardized Microsatellite”, Drew Ex Machina, July 5, 2014 [Post]

“Vintage Micro: The Original Nanosatellite”, Drew Ex Machina, February 5, 2015 [Post]

“Vanguard 2: NASA’s First Successful Satellite Launch”, Drew Ex Machina, February 17, 2021 [Post]

General References

John P. Hagen, “The Viking and the Vanguard”, in The History of Rocket Technology, edited by Eugene M. Emme, Wayne State University Press, pp. 122-141, 1964

Richard Lewis, Appointment on the Moon, The Viking Press, 1968

Constance McLaughlin Green and Milton Lomask, Project Vanguard: The NASA History, Dover Publications, 2009

J.A. O’Keefe, “Determination of the Earth’s Gravitational Field”, in Space Research: Proceedings of the First International Space Science Symposium, edited by Hilde Kallmann Bijl, Interscience Publishers, pp. 448-457, 1960