There are FIVE distinct levels to the Atmosphere of Earth....
The main problem with Naca/NASA and it's quest to have a ship/vehicle leave Earth and attain space flight was just how does a craft designed by man escape Earth's DENSE atmosphere?
Getting through each layer, Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere, was like punching through the walls of a building, with each room entered having radically different composition and temperature.
And, once you achieved that, there was the problem of returning to Earth without BURNING up from the friction....
That is why the APOLLO Capsules have those huge, flat bottoms. The TEFLON and other coverings were designed to burn off gradually as the ship descended through the atmosphere...merely absorbing the extreme heat was not enough.
NOW: In order for our Space Shuttles to return to Earth, the way that they are designed make it IMPOSSIBLE for the ships to merely drop through the atmosphere like a returning Apollo craft.
The Shuttles would simply burn up.
In order to return to Earth, the Shuttles must REVERSE engines, decelerate, then reduce it's orbital perigee. The Shuttle must go around the Earth a few times before attempting to land.
Imagine. You can fly an AIRPLANE or SPACE SHUTTLE, 600 miles around the world without a problem.
Take it straight up and try to take it straight back down to Earth and it burns up....
All because of our atmosphere.
They tell us that the Moon has no atmosphere, but the Apollo Space crafts have to go through the exact same procedures in order to land their vehicles or leave the surface of the planet.
The Lunar Lander must Circle the Moon and slowly alter it's orbital perigee in order to land safely upon the surface.
WHY, if there is NO ATMOSPHERE and 1/3 the GRAVITY of Earth?
Buzz Aldrin states that they had to leave a lot of the equipment they came with behind, LIGHTEN the load, in order to achieve enough thrust to leave the Moon....
WHY, if the GRAVITY is so reduced on the Moon? The capsule was DESIGNED to be able to leave with SAMPLES from the surface, in addition to the original equipment. The only things that were to be left behind were scientific apparatus and the launching section of the Apollo Lander. They had this figured out to the last ounce.
But they DID NOT consider ATMOSPHERIC DRAG and GRAVITY greater than was believed at the time....
So, there MUST BE an ATMOSPHERE on the Moon......