A memoir is a type of autobiography wherein the main content of a written material is about the writer.It is a genre of literature that involves writing about certain aspects and concerns of a personâs life. memoir is a type of autobiography wherein the main content of a written material is about the writer.
There have been about 8000 man made objects launched into space - only a handful left Earth orbit. Some have decayed and reentered. There are about 3000 satellites currently in orbit. Only about 1000 of those are active. But there are other objects, too, such as spent rockets. Some objects have broken apart because of collisions. There are about 20,000 objects in orbit that are 10 cm in diameter, or larger.
There are at least 24 operational GPS satellites at all times plus a number of spares. The satellites, operated by the US DoD, orbit with a period of 12 hours (two orbits per day) at a height of about 11,500 miles traveling at 9,000mph (3.9km/s or 14,000kph). Ground stations are used to precisely track each satellite's orbit. Here is an interesting comparison.