Although the structures, facilities, and other artifacts at the Nevada National Security Site represent many intriguing projects, I focus on Project Rover, which created several generations of nuclear-thermal engines. My oversimplifi ed descrip-tions of this project are based mainly on Dewar ( 2004 ), Finseth ( 1991 ), Fishbine et al. ( 2011 ), Sandoval ( 1997 ), and Spence ( 1968 ). Dewar ( 2004 ) engages both the technological challenges and, in excruciating detail, the political context.
Carried out from 1955 to 1973 at a cost of $1.45 billion (Dewar 2004 :319), when the USA and the Soviet Union were competing for preeminence in rocketry and space-exploration technologies, Project Rover’s expected outcome was a nuclear- thermal engine capable of propelling a rocket. Calculations had shown that such an engine could achieve a far greater power density than one fueled by chemical reac-tions, and so might cut travel time or permit a heavier payload. And unlike the solid- fuel chemical engines of that time, a nuclear-thermal engine could in principle be started, stopped, and restarted. Because the engine would spew radioactive gas, however, it could not serve as a rocket’s fi rst stage.
Throughout its existence Project Rover was about research and development, with no fi rm applications agreed on by federal agencies, Congress, and Presidents from Eisenhower through Nixon. Some proponents envisioned it as the third stage of a Saturn V rocket; others suggested that it could be used in a spacecraft for ferry-ing people and supplies between an earth-orbitferry-ing space station and a lunar base (Dewar 2004 , chapter 13). None of these proposed missions led to a consensus on the part decision-makers. With no designated missions, budgetary constraints at the height of the Vietnam War eventually led to the project’s termination despite its technological and scientifi c successes.
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The basic operating principles of a nuclear-thermal engine, already envisioned during the late 1940s (Bussard and DeLauer 1958 :1–3), are straightforward.
Because a nuclear reactor’s core generates a massive amount of heat, it can raise the temperature of a gas fl owing through it to more than 2,000°C, preferably a gas of low molecular weight. When liquid hydrogen, which has the lowest molecular weight of any element, is pumped through a reactor’s hot fuel elements, it vaporizes immediately, expands enormously, and escapes through a nozzle, thus yielding thrust. The fl ow of hydrogen also performs the essential function of cooling the core. Early tests were carried out not on complete engines but on reactor cores, as investigators grappled with many design problems.
Although a nuclear engine’s basic operating principles are simple, embodying them in functioning hardware was devilishly complex. Like the Manhattan Project, Project Rover spawned a vast array of subsidiary projects that created new apparatus and new generalizations. Moreover, reactor and engine tests necessitated new kinds of massive structures. Accordingly, during the life of Project Rover at least fi ve large building complexes and other facilities were constructed at the Nevada National Security Site dispersed over an area of about 30 square miles. Structures in these complexes were modifi ed as testing activities changed, and new ones were built.
Project Rover passed through several stages corresponding roughly to families of reactors and engines (Finseth 1991 ). The fi rst stages, ca. 1959–1964, were Kiwi A and Kiwi B, in a reference to New Zealand’s fl ightless bird of that name, for these reactors were intended to be earth-bound, used only for evaluating and tweaking designs. By the end of Kiwi B, the nuclear-thermal design had achieved consider-able maturity, although not all performance requirements had been fully met. The next stage, Phoebus, lasted from about 1965–1968, and led to a generation of pow-erful and sophisticated engines. Tests of NRX engines overlapped temporally with the later Kiwi and Phoebus tests. The last stage, Pewee in 1968, was an attempt to make compact engines and to test fuel compositions. Dewar ( 2004 :174–177) also mentions an XE engine, which was tested late in the project’s history. The reactor and engine tests were performed on test stands, and none ever powered a rocket.
Project Rover technologies were designed and constructed at Los Alamos and, especially in later years, at the facilities of several major contractors (Fig. 1 ).
Investigators at Los Alamos also undertook numerous subsidiary projects and ana-lyzed reactor components after tests. Many sites at Los Alamos have been described and assessed in compliance reports crafted by historians and architectural historians (McGehee and Garcia 1999 ; McGehee et al. 2004 , 2009 , 2010 ). Although apparently lacking archaeological input, the reports manage to make explicit Project Rover’s footprint on the landscape because they contain maps, aerial photographs, myriad architectural drawings, historical and contemporary images of structure exteriors and sometimes interiors, and descriptions of the structures’ functions and any alterations.
Some structures, the reports note, had been built before Project Rover but were remod-eled. Recall that Los Alamos is a vast complex, consisting of myriad Test Areas (TA) and associated structures situated on many mesa tops. Work on Project Rover was conducted mainly in buildings at TA-18 (the Pajarito site), where investigators designed the reactors in their varied iterations, carried out experiments, built many
Project Rover: A Nuclear-Thermal Rocket Engine
components, and conducted low-power tests, sometimes on mock-ups (McGehee et al. 2009 ). Work on fuel elements was also conducted in structures at TA-21 and TA-46 (McGehee and Garcia 1999 :43; McGehee et al. 2004 ).
Although few pieces of equipment from Project Rover remain in Los Alamos structures, by employing use histories as well as historic photographs of interiors, it should be possible to infer activities and equipment in the spaces depicted on the architectural drawings.
Tests of Project Rover reactors and engines were conducted in Area 25 (origi-nally Area 400), located in the southwestern portion of the Nevada National Security Site in an area called Jackass Flats. Like Los Alamos, this area is today controlled by the Department of Energy. Activities included fi nal assembly, testing, and post-test disassembly and examination (Fig. 2 ); the reactor’s fuel components were encased in shielding and sent to Los Alamos for detailed analysis.
Archaeologists, assisted by an architect, architectural historian, and professional photographer, described and assessed four facility complexes in Area 25, in some cases before anticipated demolition.
The earliest assembly and maintenance facility, R-MAD (Reactor Maintenance and Disassembly), was located in building 3110, constructed for that purpose in 1958 (Drollinger, Goldenberg, and Beck 2000b ); associated support buildings also received some survey coverage. Encompassing some 61,290 sq. ft. on several levels,
Fig. 1 Welding the body of a Kiwi A reactor in Albuquerque (courtesy of Los Alamos National Laboratory)
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R-MAD was described and photographed inside and out. The report is generously illustrated, including some historic photographs and fl oor plans. Researchers divided R-MAD into “three functional sections: an administrative area, the assem-bly area, and disassemassem-bly area” (p. 7). These areas contained “offi ces, shops, rest-rooms, assembly and disassembly bays, hot cells, viewing galleries, and work stations” (p. 7). Although part of the structure was reused after Project Rover ended, the images reveal that much original equipment remained, including electronics- intensive control rooms and work stations, heating and cooling system, a cavernous hot room with equipment for disassembling the highly radioactive reactors after testing, and, throughout, many unidentifi ed installations. Drollinger, Goldenberg, and Beck ( 2000b :1) recommended that R-MAD be considered eligible for nomina-tion to the Nanomina-tional Register. On April 8, 2010, it was demolished. 2
Fig. 2 Technician using manipulator arms for chemical analysis of reactor materials, ca. 1969 (courtesy of Library of Congress Prints and Photographs Division)
2 For a video of the demolition of R-MAD, see http://www.youtube.com/watch?v=xvC1rc3Sd4M , accessed 21 February 2012.
Project Rover: A Nuclear-Thermal Rocket Engine
Although R-MAD no longer exists—except for traces visible on aerial images and as debris somewhere—the availability of historic photographs and engineering records (Drollinger, Goldenberg, and Beck 2000b furnish inventories of both), fl oor plans, tech-nical reports, reports to Congress, and the compliance report’s detailed architectural descriptions would enable an archaeologist to offer an apparatus-rich reconstruction of the fl ow of activities in the assembly and disassembly of engines that could be integrated with the research and development activities taking place at Los Alamos.
At R-MAD, the Kiwi project refi ned and tested reactor designs, validating that it was possible to make a nuclear-thermal reactor with suffi cient thrust to propel a rocket. Phoebus project activities, in developing more powerful engines capable of longer operation, took place mainly in a new facility, E-MAD (Engine Maintenance and Disassembly). E-MAD is a windowless complex similar in functions to R-MAD but larger at 75,000 sq. ft.; it was constructed during 1962–1965 at a cost of more than $50 million. After Project Rover ended, E-MAD was reused to test concepts for handling and packaging spent fuel from commercial reactors (Beck et al.
1996 :40). Planning to lease part of E-MAD for a commercial aerospace venture in the mid-1990s, the Department of Energy commissioned a historical evaluation in anticipation of decontamination activities.
The archaeological and architectural survey of E-MAD (Beck et al. 1996 ) and ancillary structures found that much original equipment remained, including giant manipulator arms in the disassembly area, master control center with electronics, several rooms with control panels, and machine shop with tools. Also found were boilers and electrical equipment, emergency generator, a locomotive and spe-cially designed rail car for transporting completed engines to and from the test cell 2 miles away (Fig. 3 ), blast doors, and many unidentifi ed apparatus and installations. Researchers documented the rooms with functional descriptions and 107 contemporary photographs, and recommended that the E-MAD complex “be considered potentially eligible” for nomination to the National Register (Beck et al. 1996 :4). On the Internet are many aerial photographs of the complex taken at different times.
In addition to surveys of R-MAD and E-MAD, researchers were hired to describe and assess two test cells, A and C, to which the reactors and engines were transported by rail for tests and brief periods of high-power operation. Test Cell A consists of the main building (3113/3113A) of 4,390 sq. ft. and more than a dozen ancillary structures, including an enormous dewar for holding liquid hydrogen, a bunker, and a tank farm. The survey, with special attention devoted to the main building, was carried out by Beck, Drollinger, and Goldenberg ( 2000 ), who point out that this complex was “the fi rst nuclear rocket reactor testing facility in the United States” (p. 13); the report (pp. 14–16) lists the Kiwi and NRX tests conducted there from 1959–1966 (Fig. 4 ). They provided a room-by-room inventory, descriptions of the architecture and remaining equip-ment, maps and drawings of the entire complex, index to a database of engineer-ing drawengineer-ings at the Engineerengineer-ing Records Library (Mercury, Nevada), and contemporary photographs showing a vast amount of equipment. In addition, there is an inventory of more than 600 historic photographs archived at the Remote Sensing Laboratory, Bechtel Nevada.
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The last tests conducted at Test Cell A demonstrated that a nuclear-thermal engine could start on its own and run at full power (Fig. 5 ). At the time of the survey, “Test Cell A has remained untouched since its deactivation in 1966 and retains its integrity” (Beck, Drollinger, and Goldenberg 2000 :18). This complex was a remarkable fi nd, essentially a time capsule whose further study might reveal many new details about Project Rover—assuming that the Department of Energy has not destroyed it.
Test Cell C, built in 1961, had a larger main structure (10,350 sq. ft) and greater capabilities than Test Cell A; it also included ancillary structures (Drollinger, Goldenberg, and Beck 2000a ). During its lifetime Test Cell C underwent many additions and modifi cations, in part to handle newer reactor and engine designs. Tests were carried out from 1962 to 1972, including many at full power (Drollinger, Goldenberg, and Beck 2000a :Table 1). After Project Rover’s demise, Test Cell C was reused by the U.S. Geological Survey for the Yucca Mountain Project and in the 1990s by the military “to practice infi ltration and urban warfare tactics” (p. 14).
Drollinger, Goldenberg, and Beck ( 2000a ) surveyed Test Cell C, focusing on the main structure (Building 3210). The research procedures and information gathered were similar to those for Test Cell A. Photographs in the report suggest that, despite later uses, some original equipment remained, including infrastructure.
Fig. 3 Railroad moving Phoebus 2-A, April 1968 (courtesy of Los Alamos National Laboratory) Project Rover: A Nuclear-Thermal Rocket Engine
Engine tests at Test Cells A and C were conducted immediately adjacent to the main buildings (Fig. 6 ). Because of the dangers of radioactive exhaust and a run-away reactor, the tests were operated from the Remote Control Point, a building complex almost 2 miles away, which received data from instruments in the test cells, transmitted by cables through a tunnel. These precautions paid off: in one test, turbulence caused by the hydrogen fl ow ejected parts of the reactor core, spewing radioactive materials, but no one was hurt (Spence 1968 ). At this writing, the Remote Control Point has not been surveyed.