Astronomy Picture of the Day . A Bucket Wheel Excavator on Earth . ... 21.11.2006 . ... The machine pictured above is a bucket-wheel excavator used in modern surface mining . ... The largest excavators are over 200 meters long and 100 meters high, now dwarfing the huge NASA Crawler that transports space shuttles to the launch pads. Bucket-wheel excavators can dig a hole the length of a football field to over 25 meters deep in a single day. ... U. Based on Astronomy Picture Of the Day ...