Even though everything that NASA did was open to the public and shown live, some people suggested that the Moon landing was a hoax and was actually filmed in a studio.
Claim: Someone must already have been on the Moon to photograph Armstrong coming down the ladder:
Response: The TV pictures came from a camera fixed to the Lunar Module and the still photos are not of Armstrong. They are pictures that he took of Aldrin coming down onto the surface.
Claim: The flag should not wave as there is no wind on the Moon.
Response: The flagpole had a wire stiffener to display the flag properly on the airless Moon. The only time the flag is seen to move is while the astronauts are setting it up. afterwards, it never moves again.
Claim: Shadows go in different directions, showing there must have been more than one light.
Response: Shadows will only be parallel if the objects that make them are parallel and the surface is flat. Rocks are not parallel to each other and the surface of the Moon is definitely no flat. In fact, the shadows prove that the photos were taken in a place with just one light source. If 2 lights were used, then there would be objects with 2 shadows.
Claim: The astronauts could not have survived the radiation from the Van Allen belts. They would have needed 6 feet of lead shielding.
Response: The astronauts did not travel along the Van Allen belts but across them, protected inside a multi-walled metal spacecraft. The total amount of radiation they received was less than a dentist uses to take an x-ray.
Claim: Without an atmosphere to scatter the sunlight, stars should be visible in the photographs.
Response: The exposures were mostly in sunlight, at a shutter speed of about 1/250 second. Stars are very faint and need an exposure of a few seconds to be seen.
Claim: The thrust from the Lunar Module’s descent engine should have left a blast crater.
Response: The Lunar Module weighed one-sixth of what it would on Earth and the 2,600 pounds of thrust was spread across the area of the exhaust, which led to a pressure of 10 pounds per square inch. When the Harrier aircraft makes a vertical landing with an engine that produces 23,800 pounds of thrust it doesn’t make a crater.
Claim: The astronauts simply orbited the Earth and came down at the end of the mission.
Response: America could track spacecraft to the Moon. They did. So did scientists at Jadrell Bank in England. If the astronauts didn’t really go to the Moon, the Russians would have been the first to say so. If the craft just stayed in Earth orbit, it would also have been visible in the night sky.
Claim: The pressure in the space suits was greater than in a football, so the astronauts should have been puffed out, making it impossible to bend and move freely.
Response: A football is normally inflated to 13 pounds per square inch, but the space suits only had oxygen in them, not air, so they only needed to be inflated to 3.5 pounds per square inch.
Claim: The liftoff from the Moon needed someone there in order to tilt the camera up just at the right time.
Response: The camera was on the Lunar Rover and was always controlled by Ed Fendell in Mission Control. He followed the countdown for the liftoff and sent a command to tilt the camera up about a second before launch, so the signal would reach the Moon just as the liftoff took place.
Claim: There should have been a flame from the ascent stage engine of the Lunar Module as the fuel burned.
Response: Not all rocket fuels produce a flame. the fuel was hydrazine with an oxidizer of nitrogen tetrozide. This combination produces nitrogen and superheated steam, which is transparent.
The McDonald Observatory in Texas still fires laser beams to the Moon to measure its distance. The beams are only bounced back from the landing sites where the astronauts carefully placed the laser reflectors.
Hundreds of samples of Moon rocks and soil have been analyzed by scientists all over the Earth. Not one has claimed they are fakes. They all agree that they are older than any rocks found on Earth; tehy show compositions of minerals that do not appear on Earth, and they show micrometeoroid impacts that are not seen on any Earth rocks.
(Content Source: One Small Step: Celebrating the First Men on the Moon.)