United States of America (1957)
Underground Nuclear Test Shaft Cap – 1 Built
The brainchild of one ambitious American astrophysicist during the course of U.S. nuclear tests yielded the first manmade object in Earth’s orbit. The four foot round steel cap was launched into orbit in late August 1957 by the United States, beating the USSR’s Sputnik 1 to orbit by one month and nine days, scoring a major victory in the space race for the Americans. This feat has gone largely unrecognized by most historians.
History
During Operation Plumbbob, which was a series of nuclear tests performed by the United States in 1957, Dr. Robert Brownlee was tasked with determining methods for containing nuclear blasts underground. Initially working from a detonation performed at the bottom of an open shaft, and progressively adding additional ‘plugs’ of concrete to ‘tamp’ the explosion.
The first empty shaft test was called Pascal A, and performed on July 26, 1957. It’s significance was characterized by the fact that it was the first contained underground nuclear test ever performed. The bomb was placed at the bottom of a shaft of about 500 feet in depth, around 3 feet in diameter. The blast yield was much greater than anticipated, estimated at around 55 tons which caused quite a stir at the test site when it was detonated. A concrete collimator with a thickness of five feet was lowered about halfway down the shaft with a detector installed on top. The concrete and detector were presumably vaporized in the explosion, which occured at night and caused a “big blue glow in the sky,” according to Test Director Robert Campbell.
Pascal B
The next test, Pascal B, attempted to measure the effect of installing a concrete plug just above the bomb, still deep at the bottom of a 500 foot shaft, with a steel cap installed at the end, where the shaft met the surface. The concrete plug, also serving as a collimator for test instruments as in Pascal A, was placed above the bomb. The plug was estimated to have weighed 2 tons.
The shaft diameter for Pascal B was 4 feet in diameter, with a round solid steel cap, 4 inches thick welded to the top. The weight of the cap was estimated to be 2,000 lb (900 kg). Dr. Brownlee designed his calculations to estimate the time and measurements of the nuclear blast’s shockwave in meeting the cap. The estimated time for the shockwave’s arrival was 31 milliseconds. It was anticipated that the pressure and temperature would launch the cap away from the shaft at an extremely high velocity, although this would not necessarily be directly a result of the explosion, since the cap was located too far from the bomb at the bottom of the shaft. Rather, the vaporization and resulting superheated gas of the 2 ton concrete collimator plug placed above the bomb would actually turn the shaft into a ‘giant gun.’ The cap was estimated to achieve a velocity six times the escape velocity of the Earth. A high speed camera was installed nearby with the hopes of capturing the cap’s departure, to hopefully obtain a calculation of the cap’s speed as it left the shaft.
At the Nevada Test Site on August 27, 1957 at 3:35 PM local time, Pascal B was detonated with a yield of 300 tons. The fireball reached into the blue Nevada sky, launching the cap as expected. The high speed camera recorded the cap above the hole in only one frame of the resulting film. The anticipated velocity values combined with the framerate of the camera did not yield any specifically useful measurements, leading Dr. Brownlee to sum up the speed of the cap as “going like a bat!” The original calculation of six times the escape velocity of the Earth of 41.75 miles per second (67.2 km/sec) seemed to have been approximately correct. Other calculations by Carey Sublette that attempt to estimate the expanding gas of the vaporized concrete collimator indicate a similar figure of around five times the escape velocity.
First Manmade Object in Earth Orbit
Whether or not the cap actually made it to space is still a topic of debate. No trace of the cap was ever found anywhere near the test site. Some say it would have been vaporized in the same manner as a meteorite burning up upon entry into Earth’s atmosphere. Still others theorize that the object may have made it into Earth’s orbit. For the purposes of this article, it is assumed that the cap made it into Earth’s orbit.
The cap would not be the first manmade object in space. That honor belongs to a V-2 rocket launch in Nazi Germany on October 3, 1942, which crossed the Kármán line which is considered to be the boundary of space at an altitude of 100 km (62 miles).
Aside from the Pascal B cap, the most generally agreed upon first manmade object in Earth’s orbit is Sputnik 1, launched on October 4, 1957. If the cap in fact achieved orbit, it would have beaten Sputnik by 1 month and 9 days. This fact has yet to be widely recognized, with most people and historians believing that the USSR achieved the first object in orbit.
Design
The steel cap round, 4 inches thick, was welded to the end of the round metal test shaft, 4 feet in diameter. The cap was presumably not painted or covered with any sort of coating. More than likely the cap was machined locally along with the other significant large scale industrial milling, machining, and fabrication to facilitate the testing operations in support of Operation Plumbbob.
The cap has yet to be found in orbit by NASA, however its exact position still may yet be discovered. At only 4 feet in diameter, dark in color, and at an unknown orbital position, it is difficult to estimate its potential location.
Operators
- United States – Originally launched from the Nevada Test Site in 1957, the Pascal B Cap remains in service in Earth’s orbit despite its unknown location.
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