Well, there have been some amateurs that have experimented with some rudimentary guidance systems. Most have done something like lock onto the sun for a reference point or use some sort of magnetic or gyroscopic inclinometer to adjust fins.

What I just have a hard time comprehending is how a 20 foot rocket, even if it's stuffed full of solid propellant, can have enough power to get as high as they propose without staging. As I stated, I saw some huge hobby rockets that were basically that. They used ammonia perchlorate as their propellant which is the same stuff the shuttle solid rocket boosters use so I'd imagine it's about as good as it gets. These rockets might hit 60,000 feet but that's really pushing it. The hobbyists really had to design some strength (and thus weight) into their casings (many used carbon fiber composites) to be able to endure the multi-mach speeds.

In almost all cases where the amateurs were going for altitude records, they went with peroxide hybrids instead of the solid propellant. Nearly all were staged as well. Have there been some breakthroughs on solids that I don't know about?

Art