The "Orion Project" was no easy way to space,you would have to make such a stucture that would handle the blasts. it is "High tech".
I consider anything that was possible in the 1950s to be "low tech" compared to the stuff that ic2 and gregtech introduces as it is.
The orion project was designed to be made using technology from the late 1950s, or early 1960s, it is about as low tech of a system for getting off the planet as you can get.
As of now, the Orion project is the simplest, easiest. fastest and cheapest way to get a large structure into space, the only downside is that it damages the environment too much (the approximately 800 small nukes would result in considerable fallout, estimated at killing a total of 1-10 people)