Dear Mr. Cockayne,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog for “Lookout Mountain Laboratory” with 15 results, of which 5 are moving images. There may be additional records related to them which do not mention the laboratory in the Catalog description.
We also located Films Relating to Atomic Testing and Radioactivity, 1946 - ca. 1960; Moving Images Relating to Nuclear Testing, 1955 - 1964; and Films Relating to Atomic Testing and Radioactivity, 1946 - ca. 1960 in the Records of the Atomic Energy Commission (Record Group 326). Plus, we located Moving Images Relating to Joint Task Force Two, 1965 - 1970 in the Records of the Defense Threat Reduction Agency (Record Group 374).
Furthermore, a search of the Catalog for moving images with the key phrase “Atomic Test” generates 34 items in various other record series, and “Nuclear Test” produces 83 items. We suggest that you search the Catalog by the name for individual tests. For example, a search of 1940s moving images for “Trinity” produces a number of relevant results, the majority of which are from the record series Moving Images of Civil Works Projects, 1938 - 1986 in the Records of the Office of the Chief of Engineers (Record Group 77).
A few of these films have been digitized and may be viewed online via the Catalog. For access to the non-digitized films, please contact the National Archives at College Park - Motion Pictures (RDSM) via email at firstname.lastname@example.org.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgment as well as a substantive response to your reference request from RDSM. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this information is helpful. Best of luck with your research!