Unless you believe that consciousness is magic, there must be a scientific explanation to it. There is some sort of biological, chemical, electrical, or some yet unknown mechanism taking place to produce consciousness. Given a long enough time scale, we will eventually figure it out, just as we have eventually explained so many other processes in the human body.
Yes, I believe the brain can be mapped to explain human consciousness. While the brain is very complex, there have been many new advances in only the last decade to help humans better understand the brain. It is my belief that it would take a very long time to get to that point, just as it is taking a very long time for the Human Genome Project. If the human race can last long enough, I think it can be done.
I think the human brain will someday be mapped in enough detail to explain human consciousness. Knowledge of human anatomy and specific functions of organs and areas of the brain have been steadily increasing over time. It is within the realm of possibility that someday science will make discoveries that will allow for the explanation of human consciousness.
No this will not happen because it is the most complex thing. If you think about it a doctor can examine the heart, the intestines, and bones, but really the brain is not one that can be examined very easily to see what a person is thinking. You can see how a heart beats, how the intestines work, but the brain is the one that has never been examined in this type of way.
I do not thing tha the human brain will ever be full mapped enough in detail for us to explain human consciousness. I think that as amazing as science is, and as fast as it's advancing, there are still some thing we as human will not be able to understand. The human brain is one of them.