The secrecy of the mission...

I'm not sure if this has been brought up before but.... In Prometheus, it's late in the 21 century and I'm assuming this is probably the deepest mission into deep space encountered by humans. In other words, it's a 5 year deep sleep mission... this has to be pushing human's technologically expertise and the mission itself has severe implications when it comes to safety. Furthermore, the mission by Prometheus spacecraft has to be incredibly costly. So costly, one would think it would be a large broad televised event, much like the original moon missions. Obviously, it's not. The mission has to be in total secrecy. Why? Because when the Nostroma finds the beacon in the 1st Alien movie, on LV-426, the planet is unheard of. Obviously, the public was unaware of the mission. Any thoughts? And what happens to the remnants of original Prometheus film. Including the crew? Why wasn't there any wreckage in the original Alien film?