The fastest space craft in operation is the Ulysses mission to study the poles of the Sun. NASA is very carefully checking all their computers, hardware and software, to be absolutely sure nothing will go wrong as the new year begins. MRI is a painless technology used to view inside the body without using X-rays. The magnetic fields MRI uses are not known to be harmful and are painless. You can learn more about MRI at this site .
Machine guns are really clever.
The original single-barreled machine gun used its own recoil energy to keep firing. The force of the fired bullet ejected the spent cartridge and loaded the next. All visible artificial satellites do not travel from west to east. Many polar satellites occupy low orbits so are visible and travel north-south. For more information on satellites you can look at the Windows satellite page.