Well, because!
There are two definitions for excavator; one is any person engaging in excavation is called an excavator. The second definition of excavator is, of course, the vehicles called excavators, which are sometimes called diggers, trackhoes, fronthoes, and 360-degree excavators or just 360. This is not to be confused with Microsoft's vertical technology and news search engine called Excavator or xcavator, as one has nothing to do with the other.
Here we're talking about heavy duty digging machines, even though several manufacturers like John Deere, offer Compact, Midsize, and Large Excavators ranging from 0-6 metric tons for the compact excavators, 6 to 40 metric tons for the midsize, and 40 to 85 for large John Deere excavators. Additionally there exist mini-excavators, made by another manufacturer, that will fit through a door. In case you're now wondering what 3D and VRML, or actually x3D has to do with excavators, that is something we will be getting to in other articles, for right now you'll just have to trust that there is a fit. For now, however, let's get back to excavators, the digging machines used for, but not limited to: Digging, demolition, minning, river dredging, heavy lifting, and with hydraulic attachments, brush cutting. It is these same hydraulic attachments that have expanded the use of excavators, far beyond their original use of excavation such as the Low-energy Planetary Excavator (LPE) proposed by NASA. The latest paper to be found on this Nasa proposal is for 2006, so the current status can only be guessed at, nevertheless, the concept is certainly intriguing as are the LPE's possible commercial applications. Basically, The LPE would be a general-purpose machine with the ability to mine ice, regolith, and rock; it would also support construction activities. The purpose and application is meant for future manned and unmanned missions to the Moon, Mars, and beyond. .Additionally, adaptations could be made for use in extreme-low gravity such as on asteroids. This idea of efficient and reliable an excavator that has usage on differing planetary surfaces and various materials has the goal of enabling exploration and bases from outposts to self-sustaining complexes. The LPE would be able to accommodate the different materials that are encountered on planetary surfaces as the LPE would sense geologic changes and respond to them by using the lowest cutting energy possible.
Moving on the to the possible non-NASA commercial application it can be said that the same qualities of the LPE that apply to space would also attract terrestrial users or said differently, us earth bound creatures. As both business and government markets rapidly expand, so does the need for urban infrastructure. Using NASA's own words on the subject; "Urban construction settings restrict the use of explosives, to minimize damaging vibrations, making mechanical methods attractive. In addition, shallow tunnel construction is rapidly changing from cut-and-cover to wholly underground, because excavations disrupt city traffic. Coupled with increasing population, these factors enhance the market for innovatively flexible systems such as the LPE".
If I could have said it better than NASA did, I would have. But I couldn't, so I didn't. Anyway, there you have it, both the past of excavators and a look at their future with the development of the Low-energy Planetary Excavator
