Nanosatellites are generally defined as small satellites with masses in the one to ten-kilogram range. With the growing availability of off-the-shelf hardware and standardized nanosatellites like CubeSat, these tiny satellites are becoming increasingly popular among government agencies, businesses, university research teams and even do-it-yourself satellite builders with a desire to perform a range of useful tasks in low Earth orbit and beyond. One might think that nanosatellites are a recent development made possible by today’s increasingly sophisticated miniaturized technology. But in reality, the first nanosatellites were built at the dawn of the Space Age using, by today’s standards, primitive transistor-based technology as part of America’s first official satellite program known as Vanguard.
The Vanguard Program
Officially approved by the Eisenhower Administration on September 9, 1955, the Naval Research Laboratory’s (NRL’s) Project Vanguard was chosen to be America’s first civilian satellite project with the goal of launching an Earth orbiting satellite as part of America’s contribution to the upcoming International Geophysical Year – an international, interdisciplinary investigation of the Earth and its interaction with the space environment running from July 1957 to December 1958.
A cutaway diagram showing the major components of the Vanguard launch vehicle. Click on image to enlarge. (NASA)
The first stage of the Vanguard launch vehicle consisted of a lengthened Phase II Viking sounding rocket built by the Martin Company (which, after a long string of corporate mergers, is now part of the aerospace corporate giant Lockheed Martin). This new first stage was powered by a General Electric X-405 engine based on the one used in the Army’s Hermes rocket program. This engine burned kerosene and liquid oxygen to produce 125 kilonewtons of thrust. The second stage, built by Aerojet General (which is today part of Aerojet Rocketdyne), was based on the Navy’s successful Aerobee sounding rocket and used an AJ-10-series rocket engine that developed 33 kilonewtons of thrust using inhibited white fuming nitric acid and symmetrical dimethyl hydrazine as propellants. The third stage consisted of a spin-stabilized, metal-cased solid rocket motor developed by the Grand Central Rocket Company generating 11.6 kilonewtons of thrust. Vanguard stood 22 meters tall and had a mass of about ten metric tons at liftoff making it one of the smallest satellite launchers ever built.
After much debate between NRL scientists and engineers, it was decided that the “standard” satellite for the Vanguard program would be a polished metallic sphere with a diameter of 51 centimeters and a mass of about 11 kilograms. This configuration was chosen to improve the visibility of the satellite to aid in optical tracking from the ground and simplify calculations of the various forces acting on it. The interior of the satellite, in addition to a transmitter, telemetry system and batteries, held up to a kilogram of scientific as well as engineering instrumentation (see “Vintage Micro: The Original Standardized Microsatellite”).
Diagram showing the major components of the Vanguard “minimum satellite” used in the initial test flights of the program. (NASA)
In July of 1957 the decision was made by Vanguard program officials that the initial orbital test flights would not carry the standard Vanguard satellite but a small test satellite instead. This simple “minimum satellite”, as it was known, would exercise the tracking network to be used by the later Vanguard satellites and provide engineering data to help verify the thermal design of the larger standard satellites. The Vanguard minimum satellite was a polished aluminum alloy sphere with a diameter of 16 centimeters and a mass of just 1.47 kilograms making it a small nanosatellite by today’s definition and roughly comparable in volume to a “2U” CubeSat. It was equipped with a pair of transmitters operating at frequencies about 108 MHz. A ten milliwatt transmitter was powered mercury batteries while a five milliwatt transmitter employed six banks of solar cells – the first satellite to designed to use this then-new technology. The only instrumentation carried by this test satellite was a pair of thermistors to monitor the satellite’s temperature. While this test object did not carry any scientific instruments, tracking it would confirm that orbit had been achieved as well as provide information on atmospheric density and the shape of the Earth’s geoid.
Vanguard Minimum Satellite Launches
After the unexpected launch of Sputnik 1 in October 1957 (see “Sputnik: The Launch of the Space Age“), President Eisenhower was briefed on the status of Vanguard and the plans for the upcoming TV-3 (Test Vehicle-3) flight. It was stressed that TV-3 was intended to be just a test flight with the remote possibility of the “minimum satellite” reaching orbit. Future plans for Vanguard would depend on the results of this test. On October 11, 1957 the White House released a statement that Project Vanguard would launch a satellite in the near future. Immediately the press went overboard and billed the TV-3 test flight as a satellite launch. Despite its experimental status, the Vanguard TV-3 test flight ended up becoming the de facto American response to Sputnik.
On December 6, 1957, Vanguard TV-3 lifted off from Launch Complex 18A (LC-18A) at Cape Canaveral carrying the first minimum satellite. While the first stage of TV-3 ignited and began to lift itself off the pad, the GE X-405 engine lost thrust after only two seconds of flight at an altitude of only one meter. As if in slow motion, TV-3 settled back onto its launch pad, toppled over and exploded. The tiny grapefruit-sized test satellite rolled across the pad to safety and continued to transmit as the remains of TV-3 burned. The failure of what was suppose to be a just test flight struck America to its core. Immediately Vanguard was dubbed “Kaputnik” and “Flopnik” by an unforgiving press. American leaders and the public lost faith in the program (see “Vanguard TV-3: America’s First Satellite Launch Attempt“). While the next test flight, TV-3BU (Test Vehicle-3 Back Up), would fly within the next couple of months, White House officials needed more options before this public relations disaster turned into a political and military one. To increase the odds of getting an American satellite into orbit, a previously rejected proposal from a team at the Army Ballistic Missile Agency (ABMA) led by Wernher von Braun to use a modified Jupiter-C rocket called the Juno I to orbit a small satellite was approved for speedy development.
The disastrous launch attempt of Vanguard TV-3 on December 6, 1957. (NASA)
After the disastrous failure of the Vanguard TV-3 launch attempt, Vanguard’s NRL team had to pick up the pieces and get ready for the launch of TV-3BU. The contractor teams at Martin and General Electric were able to track down the cause of the TV-3 failure to a loose fuel line connection caused by technicians climbing over the engine hardware to service equipment in the rear section of Vanguard’s first stage. 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.
Work to repair the damage caused by the TV-3 explosion at LC-18A 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. 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 AJ-10 engine was damaged, the launch of TV-3BU was pushed back to February 3 so that a replacement engine could be shipped from Aerojet and installed. Since the Cape Canaveral test range could only support one launch at a time, this delay gave the competing ABMA team a brief three-day window to squeeze in a launch attempt with their Juno I launch vehicle. The ABMA attempt succeeded in placing the United States’ first satellite, Explorer 1, into orbit on the night of January 31, 1958 as envious Vanguard personnel watched on (see “Explorer 1: America’s First Satellite“.
The Vanguard minimum satellite shown mounted atop the third stage of its launch vehicle. (NASA)
As it turned out, the new February 3, 1958 launch date was a little optimistic and it was not until February 5 before TV-3BU was finally ready to fly. When TV-3BU lifted off carrying the second test satellite, 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 pitch hard downwards. 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 only 57 seconds of flight. Vanguard’s second attempt to launch a satellite had ended in failure.
After the TV-3BU failure, TV-4 was subsequently modified and prepared for another attempt to launch the grapefruit-sized minimum 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. As before, there were a series of minor delays in the countdown. At the last second there was yet another delay 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 on March 17, 1958, 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. (NASA)
Confirmation that Vanguard had achieved orbit finally came around 9:30 am EST when the tracking station in San Diego, California picked up signals from both transmitters. Vanguard 1, which was now America’s second satellite to achieve orbit, had made it into a 650 by 3,968-kilometer orbit with a period of 107.9 minutes inclined 34.25° to the equator. Initial calculations estimated that the satellite would remain in orbit until around the year 4000 AD. Vanguard had finally succeeded in meeting its commitment of launching one satellite during the IGY two years, six months and eight days after receiving official authorization. Any successes after this would be a welcomed bonus in the eyes of program officials. 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 used military rockets adapted to the task of launching a satellite, the launch of Vanguard 1 marked the first time a satellite was launched into orbit with a high performance rocket specifically designed for the task. With this successful test flight of the Vanguard rocket, subsequent launches would attempt to orbit the larger standard Vanguard satellites.
Vanguard 1 Results
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 engineering model of Vanguard 1 with its internal components displayed. (NRL)
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 led to a more refined estimate of the Earth’s oblateness. It was also discovered that the Earth’s geoid was distorted by just a few meters into a pear shape with the pointed end at the north pole and the flattened end in 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.
The long silent and often forgotten Vanguard 1 remains in orbit to this day as the oldest manmade object in space having completed over 99,000 revolutions of the Earth. With an apogee of 3,840 kilometers and a perigee of 660 kilometers (as of January 23, 2015), the world’s first nanosatellite is expected to remain in orbit for about another 180 years. Perhaps before its final destructive plunge into Earth’s atmosphere, it might be possible to retrieve this historic relic from the dawn of the Space Age and place it on display for our distant descendant to admire. In the mean time, Vanguard 1 should serve as an inspiration for today’s nanosatellite builders who have much more advanced technology at their disposal.
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Related Videos
I have been able to find old footage of the first three attempts to launch the Vanguard minimum satellite. This first video period newsreel footage of the famously unsuccessful launch attempt of Vanguard TV-3:
Here is newsreel footage of the unsuccessful second launch attempt, Vanguard TV-3BU:
Finally, 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]
“Vanguard 1: The Little Satellite That Could”, Drew Ex Machina, March 17, 2018 [Post]
“Vintage Micro: The Original Standardized Microsatellite”, Drew Ex Machina, July 5, 2014 [Post]
“Vintage Micro: The Original Picosatellite”, Drew Ex Machina, May 18, 2014 [Post]
General References
Constance McLaughlin Green and Milton Lomask, Project Vanguard: The NASA History, Dover Publications, 2009
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