GEOSTRATA Magazine

A major challenge to making celestial soil mechanics viable is to re-engineer the profession's toolkit to provide geotechnical solutions without the luxury of ex-situ and in-situ testing as we know them on Earth. It's essential to develop an understanding of fundamental mechanical, thermal, and fluidization properties of granular media on other celestial bodies. Regoliths, dusts, and other discrete loose superficial materials have — and will be — the most abundant material humanity interacts with on non-Earth explorations.

On December 5, 1944, with World War II still raging and peace in Europe still six months away, the German submarine U-864 set out on her maiden voyage on a secret mission to deliver strategic war supplies to Japan. In her hull, the submarine carried Messerschmitt jet engine parts for use in Japanese aircraft and V-2 missile guidance systems, as well as 67 metric tonnes of the strategic — and highly toxic — element mercury, which was widely used in weapons production at that time. However, on February 9, 1945, the British warship HMS Venturer detected the German submarine off the coast of Bergen, Norway, and fired off all four of its torpedoes. Hearing the incoming weapons, U-864 took evasive manoeuvres and avoided the first three torpedoes, but unknowingly steered into the path of the fourth. The torpedo struck the submarine, splitting her in half and sending her to the depths of the ocean floor approximately two nautical miles offshore, near the island of Fedje in Western Norway. All 73 of the submarine's crew perished.

Installation and maintenance of instrumentation to monitor geotechnical projects in remote locales is usually more challenging than sites in urban areas for both technical and logistical reasons. In most of the recent remote sites the authors have participated in, satellite-based technologies are playing essential, but different roles. This article introduces the roles of three different types of satellites: communication satellites, global navigation satellite system satellites, and Earth observation satellites. Coincidentally, these three satellites operate in three distinct Earth orbits. They include: the geostationary orbit at a distance of 35,786 km from Earth's surface; the medium Earth orbit at a distance of 2,000 to 35,786 km from Earth's surface; and the low Earth orbit at a distance of 160 to 2,000 km from Earth's surface. The satellites use signals in different frequencies, covering a wide range microwave spectrum from the low frequency L-band (1 to 2 GHz) to the high frequency K_a-band (26.5 to 40 GHz).

Rockfall mitigation projects frequently require work at elevated positions. This is not something that comes naturally for many engineers and geologists. Palms sweat, knees knock, and voices may start to crack — all of which is completely normal. But sometimes we need to work from elevated, remote locations in order to execute project work — to get to locations that are difficult to access and seem to tower above the rest of the world. On top of any fear of heights, there are other obstacles that can hamper progress in these locations, like dealing with protruding brush, flowing water, hornet nests, snakes, and falling materials (including rocks!).

The rich, natural resources of Alaska have long been the focus of many pioneers seeking fortune in the Last Frontier. As captured in historical images of dedicated Klondike Gold Rush miners seeking their fortunes via the Chilkoot Trail, or the U.S. Army Corps of Engineers constructing the famous Alaska Highway, often the biggest challenge is getting there. Many of Alaska's resources are in remote locations where access can be limited. Given the distances that need to be covered, the difficult terrain to be crossed, and the number and type of unexpected users, remotely located resources are typically accessed via aircraft on remote landing strips. Isolated airfields are usually the least expensive and most cost-effective infrastructure to construct, making long-distance roads scarce in Alaska due to high construction and maintenance costs for long transportation corridors.

Application of soil mechanics in engineering practice has undergone remarkable changes over the past 50 years as a result of developments in computer technology. Each improvement in computing capability, speed, and information storage has opened the way toward software solutions capable of analyzing problems of ever-increasing complexity. Not only have the size and complexity of the problems changed, but the modern computer has also opened up new approaches to addressing common problems in geotechnology.