Short answers, pulled from the story.
The required velocity for low Earth orbit is approximately 17,500 miles per hour. This speed allows forward motion to balance the pull of gravity and maintain an orbital path.
NASA tracked 2,465 artificial satellite payloads and 6,216 pieces of space debris as of 1997. These figures represent the count of objects monitored at that specific time.
Spacecraft with a perigee below 200 kilometers experience drag from Earth's upper atmosphere which decreases the orbital altitude continuously over time. Below 160 kilometers decay becomes rapid enough that lifetimes measure only in days.
A Molniya orbit features an inclination of 63.4 degrees and lasts about 12 hours so such satellites spend most of their time over designated areas of the Earth. This specific angle allows for extended coverage over high latitude regions.
The average distance to the Moon is approximately 384,400 kilometers while geosynchronous satellites circle Earth at exactly 35,786 kilometers. This difference places the Moon far beyond the boundary of medium Earth orbits.