Low Lift 3rd Stage

The 3rd Stage Sigma-class booster was speficially designed when it was mentioned that the High Orbital Transfer Station was on the agenda to be constructed. To be used in conjunction with the 1st Stage Delta-class and the 2nd Stage Gamma-class boosters, it's primary purpose was to push the sections of the station into a higher orbit, assisting in attaching the parts into their higher earth orbit.