Complex sentence: A sled track that gave a Mach 2 or greater launch assist could reduce the fuel to orbit by 40% or more, while helping counter the weight penalty when aiming to make a reusable launch vehicle to reduce launch costs.
Split into simpler sentences: A sled track that gave a Mach 2 or greater launch assist could reduce the fuel to orbit by 40% or more. Such could help counter the weight penalty when aiming to make a vehicle reusable to reduce launch costs.