Do you think NASA is hiding proof of intelligent alien life in the solar system

What would be the purpose of denying their existence?

I think the government is and maybe that's why we don't have a drill/submarine on Europa yet. Major Marcel who was one of the few people to see the wreckage from Roswell claimed to have left the room briefly and when he came back and it was full of weather balloon wreckage, but when he left it was an aluminum type material from the ship. He has a look of disbelief at what he is holding in the famous picture because he claims the material was switched. You can see by the look on his face that he can't believe what had just happened

Most definetly they are.

1. The aliens have threatened them with oppression or death should they tell the people what they know. Still, Buzz Aldrin and Neil Armstrong, the most famous astronauts ever who landed on the moon have both repeatedly in their old age stated publicly that they saw aliens and were warned to stay quiet. It is tough to intimidate a person who knows they don't have long to live anyway. That people continue to ask this question after these two great Americans have settled it is an insult to the intelligence of humanity and the bravery of these two pioneers.

2. The aliens have proved they are extremely hostile and many people have been tortured and murdered by them. It is tough for a person who knows the whole truth like I do to blame our government for coving up the existence of this malignant and undefeatable force. People have almost as much right to be protected from the truth as they have to know it.

No.

In any case, NASA is certainly not the only organization that studies space.

I have a hard time imagining an Iranian astronomer asking NASA's permission before publishing an article about life on other planets...

In fact, I have a hard time imagining most American astronomers asking NASA's permission...