I recently stumbled across an interesting discussion on Steve Wilson’s blog, of the various definitions of space archaeology (in two parts, here and here). The focus is mostly on three intersecting subcategories of space archaeology: aerospace archaeology – the archaeological study of flight and space exploration, exoarchaeology – investigation of archaeological sites located off the Earth, and xenoarchaeology – the archaeological study of past non-human cultures. (He illustrates the overlapping nature of these three sub-fields with this chart.)
Xenoarchaeology, arguably the most interesting of the three, is obviously purely speculative at the moment, as no confirmed evidence of non-human cultural activity has yet been found. (The study of stone tools and other artifacts manufactured by hominids other than Homo sapiens could presumably be considered xenoarchaeology, but in practice the term is not used in that way.)
Of course, the lack of any actual evidence has not kept vast numbers of trees from being killed to promote wild theories involving alien visitors, both ancient and modern. As far as I’m aware, William Doleman’s excavation at the putative UFO crash site near Roswell, New Mexico remains the only legitimate xenoarchaeological field investigation. A few very speculative papers have appeared (usually using the term SETA: Search for Extraterrestrial Artifacts), but I am not aware of any that have been authored by archaeologists.
However, the other two sub-fields, aerospace archaeology and exoarchaeology, have become mainstream enough to be discussed in a space archaeology symposium at the recent SAA conference. The focus of the symposium was on the preservation of our aerospace cultural heritage, rather than investigating aerospace sites, which is perfectly understandable. Most of the questions that space archaeologists could address involve unique events (i.e., why and how did a particular space vehicle malfunction), rather than the patterned cultural behavior that is more properly the subject of archaeological investigation. In addition, on site investigation of archaeological remains located off Earth is likely to remain prohibitively expensive for the foreseeable future.
Investigation of exoarchaeological sites using remote sensing* is a more practical approach, and some types of projects have already been carried out. (Phil Stooke’s tracing of the path of the Lunokhod 2 rover last March being one example.) More ambitious projects may be able to piggyback on future space missions. If a sufficiently compelling research question can be devised, it might even be possible to fund a space mission specifically for an archaeological purpose (although the current state of the economy makes that appear unlikely in the near term).
As I stated, aerospace heritage preservation was the primary focus of the speakers at the SAA conference. This mainly involves legal and political action right here on Earth, and significant work can be done at a much lower cost than even the cheapest space mission. It is also somewhat urgent, given the potential that space tourism and other private space ventures have to damage irreplaceable heritage sites.
Presently, NASA’s concept of space archaeology is largely limited to the use of satellite remote sensing to study archaeological sites on Earth. This is itself a fascinating and important subject, but I hope that within the next few years they will also develop an interest in some of the other aspects of archaeology in, or involving, outer space.