Kind of a spin-off of the GPS ideas.
A two part machine to launch satellites into orbit. First part would be to build a launchpad machine. Second part would be to build one time use payload capable rockets to launch from the launchpad.
Uses: Satellite for GPS as mentioned in another thread. Orbital microwave energy collector that links to a ground based collector (full time solar generator). Kinetic strip miner: launch a rock with a guidance system, place remote target, fire the kinetic round from space with a remote like dynamite. All this for a big hole in the ground. Weather satellite; stage one gives time warning to weather changes, stage two allows you to control the weather. Plus whatever else seems useful to stick into orbit. Or how about a trip to the moon as another form of the Nether. (you did remember to build another launchpad and shuttle rocket before you went to the moon didn't you?)
Thoughts: Launchpad could be fairly simple and cheap to build. Rockets...not so much. Rocket are built in stages; propulsion, payload, and guidance. Each one is basically an advanced machine built separately, then assembled for launch. Place the assembled rocket into the launcher and fire remotely. At launch, a controlled blast (say 1 high by 3 wide centered on the launcher) will clear anything near the launcher.