A massive airplane being built by Microsoft co-founder Paul Allen moved a step closer to flight last week, when it crept out of its hangar in Mojave, Calif., and practiced rolling down the runway, hitting a top speed of 46 mph.
Known as Stratolaunch, the plane has a wingspan even greater than that of business mogul Howard Hughes’s famed Spruce Goose and is designed to carry as many as three rockets, tethered to its belly, to about 35,000 feet. Once aloft, the rockets would drop, then fire their engines and deliver satellites to orbit. -- http://archive.is/QLfIj
This is huge! The Saturn V that took American astronauts to our Moon burned 1/10th of its fuel load just clearing the launch tower. This platform will give them a 35,000 ft and 500 mph head start. That means you can get the same payload to orbit for much lower costs.
Edit: here's a picture: https://imgoat.com/uploads/2cc227532d/91919.jpg
Edit2: If I had designed that thing, I would have eliminated the outboard portion of the horizontal stabilizers and joined the 2 inboard sections. It would make the whole thing a lot more rigid. The way it is now, it looks very spindly, like it's going to break in the middle of that wing. I might not know anything, but I have a strong suspicion that airplane design is a lost art in this country.