Is it currently possible to build a 500 ft roller coaster?
Yes, it is possible. However, I’m assuming if they wanted to build one that high, then they will make it a launched coaster. Which is pretty much the reason why I think they won’t do it anytime soon. A lot of launched coasters are constantly down because of problems with their launch mechanisms. Also, if you were to build a roller coaster over 500 feet tall, or let me say, one with a 500 foot drop, that would be some extreme G-Forces on your body, So if there is ever one built, it will probably be similar to other strata coasters (coasters over 400 feet, maybe they will make a new term for 500 feet+ if they ever build one, but I will just call it a Strata for now.) such as Kingda Ka. http://www.rcdb.com/2832.htm?p=0 It is a very short ride with just one Top Hat hill and a small (in comparison) 169-foot camelback hill. So, yes, it is possible, but I don’t see it happening soon because: -it might not attract a lot of riders because strata coasters are so short in ride time -it will cost
