Using high-tech remote sensing methods, a collection of artifacts has been unearthed at Stennis Space Center near Bay St. Louis, MS. The objects uncovered during archeological excavations conducted over the past 11 years were found at the site of the 19th century Hancock County seat on the Pearl River, which is now part of the space center. Dr. Giardino was one of the archeologists involved in the dig.
NASA Tech Briefs:Why is NASA conducting archeological excavations?
Dr. Marco Giardino: The site is part of the space center's buffer area and is therefore one of the cultural resources that we are mandated to manage in line with federal and state legislation. It is a preservation and conservation effort on the historic resources that we own.
NTB: How was NASA technology utilized during the excavation?
Dr. Giardino: While the ground-penetrating radar was not developed at NASA, the application of it is innovative from NASA’s point of view. We combine high-resolution satellite and aerial imagery with a series of non-destructive ground remote-sensing technologies, which includes the ground-penetrating radar. In addition, we innovated the ability to take historic documents, typically surveys and plats [chart or map of a piece of land], and co-register them to modern imagery. The combination of these three sets of data – the data satellite airborne imagery, ground-penetrating radar, and the historically registered plat documents – give us a much better indication of where to dig, what to preserve, and what to avoid.
NTB: How was the remote-sensing technology more beneficial than other archaeological methods?
Dr. Giardino: For a site that normally has not been investigated, you have to do a sub-surface survey using an auger or a shovel, and dig a hole every so many feet or meters. In large areas, like the town, this is a very expensive and time-consuming effort. Utilizing the three layers of data mentioned before, it becomes much easier (especially when equipped with a GPS) to go out into the site and identify those areas of particular interest for investigation. For instance, we know from old newspaper articles and an old plat where the hotel was located. The hotel is of significance because of the person who owned it and the artifacts that could be found in it. Once you have that information on your computer screen, in terms of all those different sensors used together, you just load up your GPS, get the coordinates off of the screen, and basically walk up to whatever part of the site you want to start excavating. Obviously this saves a lot of time and effort, and really focuses where one has to invest to do the research.
NTB: What are some new research methods that resulted from the excavations?
Dr. Giardino: We were really impressed by two things: We started this process by translating the diary entries into geographical locations. We were amazed at how accurate the surveyors were at the time using such crude instrumentation. The same revelation occurred to us when we started to get these early British and French documents and registering them to our map. The first insight was that these surveyors were no slouches.
The second approach was that we were able to do a lot of non-intrusive work with these instruments. We partnered with the University of Mississippi to bring on other geophysical prospecting tools. One of the things that immediately became evident was that we were able to cover large areas of ground and then take the results and put them in a 3D virtual rendering environment. This allowed us to perform analysis in an immersive environment where, in fact, you could peal off the radar signals layer by layer and immerse yourself in a “test pit” and be able to look in all four cardinal directions and see what the radar had seen. You could overlay that information with the actual excavation and you can match signals with the real strata in the excavation. This not only helps with the analysis and the research, but also from the outreach and education point of view where you can load these virtual renderings on to a geo-wall or in a large theater setting and allow the public to experience both the archeology and the recreation of the town, which we have been able to do from old photographs and the like. This way a person, without coming on site, can virtually tour the old town of Gainesville and pick any period they might want to tour – early prehistoric, French, or most recent historic period (1850’s and 60’s).
NTB: Could these methods be used in other fields?
Dr. Giardino: I’ll start from the simplest to the most complex uses of the technologies in other applications: the ground-penetrating radar is used in civil engineering to look for voids under highways or to identify buried pipe or those types of things. The next step up would be to use it in conjunction with a GPS so that data can be dumped right into a program, such as a geographical information system (GIS), or anything that allows for the development of maps with accurate coordinates.
The employment of NASA satellite technology, especially remote sensing technology, while not used as frequently is beginning to be used for instance you have thermal channels that could determine underground leaks or anything that has a temperature gradient, such as very cold or very hot liquids. Because of the way the signal from the satellite often matches the one from the ground-penetrating radar, once they are understood either one could be used instead of the other which means that any commercial institution that wanted to do that type of work does not have to buy both.
The most advanced effort going on now is the visualization or rendering of the signals and data in a way that is understood by the public. For example, an electric company that wants to find underground pipes or conduits would run simulations virtually and immerse their technicians in that environment to allow them to switch components and parts, run currents through, see what the impact is, and therefore save a lot of time and effort, rather than digging first.
With the environment that we’re in here in Mississippi after hurricane Katrina, there are a lot of applications for just finding buried gas pipes because the features on the surface are pretty much gone. The combination of the methods that we are using could be applicable to their recovery and rebuilding efforts.
NTB: What is the future of this program?
Dr. Giardino: The Gainesville site is set aside and preserved, and sometimes we run teacher workshops down there when they’re interested in history and archeology. The methodology has been exploited by other NASA centers because one of the things that we do is combine all of the data that we talked about and then develop GIS predictive models for the entire site. For example, knowing the parameters that define the location of known sites, you enter those parameters for the rest of the area and then define high- and low-probability areas for additional sites. Other centers, like Kennedy and Marshall, that have large land holdings can benefit from this.
We also have expanded from the historic village to the 30+ NASA historic landmarks that include our test stands, the Apollo I test stand, and wind tunnels and such. We are now purchasing some very accurate laser equipment the render the buildings as they are today and manipulating them virtually to recreate the environment of when they were historically significant. The Apollo I test stand at Kennedy, for instance, is basically just a metal frame now, but in this virtual environment you can recreate it accurately to what it was when it was active. All of NASA’s holdings that have historic relevance are or will soon be experimenting with this approach.