BillyBlazeIRL

The challenge is to land on the Mun and return using only solid fuel engines. I've been trying to do this for awhile, but I'm sure someone better than me is capable of this. I suspect it would involve and lot of decouplers and boosters.

Another thing that can cause the plane to swerve is the landing gear failing. When there is a lot of weight on landing gear, they can lock up and cause the plane to swerve. This used to happen to me all the time. I started attaching struts to the landing gear, and it fixed 100% of my problems. Definitely worth a try.

Mach 1 would be way different that high up, but that's neither here nor there. That really is pretty slow. Its easy to get up to 1000m/s with nearly any plane.