Well you did not define if you want an explanation for astral projection in "inner realms" or other simulation of reality or including the perception of information on the objective world. As I said, the one without the contact with objective world is known by all to exist, it takes only practice.
Anyway, there are a lot of ways to gain information. I trust my family and I have another cousin who told me of two times she woke up in panic in the middle of the night thinking of death only to find out in both times important people for her had died tragic deaths.
Another even more convincing example is when a person living near my family dreamt she was being suffocated in the same day a person of the family was suffocated by robbers until passing out. This was before cell phones and the dream was told before anyone knew of the robbery.
So you have one family, over 3 curious events. That's to show how common these things are, having an explanation or not. When it starts happening too much against the odds, you might consider a connection and not always coincidence. Information like the experiment I mentioned with Tart or the claims of physicist Thomas Campbell serve only as evidence that has to be thought about: Are these people honest? If such things as ESP exists, would we not have these kind of evidence of people that experienced it, and some of them went on to do experiments and write books?
Here is another one by Charles Tart:http://www.issc-taste.org/arc/dbo.cgi?set=expom&id=00008&ss=1
As sad as it is, if we are considering the possibility of esp, we have to consider the possibility that there are going to be people who have had this experience and write about it like the above. It is rude to always start from the assumption "All people who say this are lying" without at least trying to know a bit about the background of the person and what it is exposing.
By all the evidence I have been given by people of trust, and also the ones I read about, be it about spontaneous or laboratory experiences, I am compelled to believe that this stuff is real.
I'm sure there are also people who do not tell the experiences that happened to them for any number of reasons, but who have had them anyway.
I think it is not necessary to exist a explanation of something in order for it to be real. And also, I'm sure there are a lot of things we take for granted that we only believe because there have been experiments or is in a textbook.
About the US Government, how long do you think experiments in ESP would take? I mean, imagine a week of doing experiments in remote viewing or other kinds of esp. Now raise that to a month. One year. 10 years, 20 years? Do you think people would persist after more than 10 years with no compelling results?
"To become a consultant on the SRI project, I had to obtain a Top Secret security clearance and sign two contracts where I agreed not to reveal what the research found. I remember those contracts well, as agreeing to secrecy of any sort was not my usual style of life! (...) Fortunately for scientific knowledge, much of what was in these classified RV programs has been revealed by various authors (Schnabel 1997), who discovered them from documents recovered through use of the Freedom of Information Act, so they're no longer secrets that I have to worry about revealing. However, a good number of the most successful results used in actual intelligence operations have never been declassified." - Charles Tart