Shuttle Imaging Radar and other spaceborne images of the Arabian desert, produced utilizing JPL technology and expertise, played a key role in the recent discovery of a lost city on the edge of the Empty Quarter in southern Oman.
A team of scientists and archaeologists from the United States, Britain and Oman have discovered the site of the legendary lost city of Ubar, a major hub for trading frankincense which dates back to the year 3000 B.C.
The location of the ancient city has been lost for centuries in the drifting desert sand. The use of spaceborne radar, a device that can penetrate the dry sand, and enhanced satellite images allowed scientists to detect tracks of caravan routes leading to the city.
"I was surprised to find that we were able to readily detect ancient tracks in the enhanced shuttle radar and satellite images," said Dr. Ronald Blom, a JPL geologist specializing in remote sensing.
"One can easily separate many modern and ancient tracks on the computer enhanced images because older tracks often go directly under very large sand dunes. We could never have surveyed the vast area where Ubar may have been, nor could we be confident of its location without the advantage of computer enhanced images from space," Blom continued.
Analysis of the images was used to direct ground reconnaissance expeditions throughout the region in the summer of 1990 and the fall of 1991. The result of this work led the expedition to the site of a remote well on the edge of the Empty Quarter.
There, the explorers uncovered the remains of towers, rooms and other artifacts that appear to date back to before 2000 B.C. The great variety of artifacts discovered at the site demonstrates that it was an important trading center linked by extensive trade routes to Mesopotamia and the Mediterranean.
JPL's involvement in the search for the lost city of Ubar dates to 1981. Nicholas Clapp, a Los Angeles documentary film maker, contacted the Laboratory with the idea of using the Shuttle Imaging Radar to look beneath the sand of the southern Arabian desert.
In 1984, the shuttle Challenger made two passes over an unmapped region of southern Oman and studied the area with Shuttle Imaging Radar B (SIR-B).
Since then, Dr. Charles Elachi, JPL assistant laboratory director of the Office of Space Science and Instruments, Dr. Robert Crippen, a JPL research geologist, and Dr. Ronald Blom have continued looking for Ubar from space using radar images taken from the shuttle and other images taken from the U.S. Landsat 5, the French SPOT satellite and the shuttle-borne large format camera.
Other members of the expedition include Nicholas Clapp, a Los Angeles based documentary film producer; George R. Hedges, a Los Angeles attorney; Dr. Juris Zarins, an archeologist with extensive experience in Arabia; and Sir Ranulph Fiennes, the famed Arctic explorer.