Shuttles are hard to fly, in order to fly one in SFS you need to look at some space shuttle tutorials and facts, me personally likes the average space shuttle, here’s a tip to how to fly one: try going to h to the right instead of left, if you go left it will flip back and make you crash, once in the stratosphere in the game, near the karma line at 30 KM, release the SRB’s then, continue flying while transferring fuel to the engines, once in a decent half-orbit around SFS earth or modded SFS earth, release the External Tank, Then turn off the main engines and turn on a Valiant or a Frontier, Once your in a perfect or near perfect orbit you can wait a bit if you so choose, once you wanna land de orbit the shuttle pull out parachutes, you shall need parachutes in the front and back if you don’t want to crash, make sure to add heat shields due to Re-Entry.