You wouldn’t know it by listening to many conspiracy theorists, but NASA is by far the most open space agency in the world when it comes to publishing data from spacecraft. By law, the teams that built and run the instruments on these missions must publish their data within six months of it being taken, except in rare cases when an additional six-month extension can be granted.
Contrast that with the Chinese and Indian space agencies, which still haven’t openly published data from missions that completed several years ago. Japan is better, as is the European Space Agency (ESA), but neither of them supply data as readily and easily as NASA.
In addition to the rules for depositing the raw, unprocessed data, NASA’s PR department, along with the PR arms of most missions, publish some of the data online almost as soon as it’s taken. This is great for the public; it’s also terrible for skeptics.