…in this article about which asteroids are good prospects for human visits. It should just jump right out to regular readers. I’ll reveal over the fold:
A heavy-lift launch vehicle capable of delta-V greater than 7.5 km/sec. is required for any of these missions to happen.
Ignoring the issue of what it meant by “delta-V greater than 7.5 km/sec” (hyperbolic excess? Usually this is described in terms of C3), you do not need a heavy-lift vehicle to do that. A propellant depot will do the job quite nicely, and isn’t constrained in size or delta-V by launch facilities.