Lockheed Martin Athena I
This is Lockheed Martin's Athena I Launch Vehicle. A privately funded design that was supposed to support the MEO (Medium Earth Orbit) satellite market. They had 4 launches of the Athena I and 3 launches of the Athena II before the market went away. Without a customer, Lockheed Martin ended the line.
The design was pretty simple. A solid-fueled first stage motor with a solid-fueled second stage, all topped with a hydrazine fueled orbit adjust motor. Simple, and effective. There was only one failure out of the 7 launches they made. Eventually an Athena III would have been developed with either two, four, or six strap-on boosters added, but the market died.
Still, they managed to launch a couple 'big name' space craft like the Lunar Prospector probe. If the market hadn't died this might still be around.
A Simple Build
This model was designed by E. te Groen, and is found at http://www.lansbergen.net (click on "modelbouw"). It's a nicely detailed model, just waiting for someone to come along and super-detail it. In fact, it was. David Hanners is a very talented modeler, so you should check out his other models in the gallery there.
Anyway, back to my model. It went together quite quickly, and easily. In part due to the design, and in part due to the simple shape. It's a tube and a cone. Not so tough, but still easy to screw up if you aren't careful. Also, adding the extra detail parts is almost a no-brainer. I did it different though. I didn't fold them over, but rather glued the paper to card stock, colored the other side with a Sharpie, cut them out, and glued them on. Easier to make and sturdier too.
I'd say more about this model, but there isn't much to it. Not that it's a bad thing to be simple, but it doesn't give me much to talk about. I will say that this is a great model for anyone to build. It's easy to make, nicely detailed, and ready for super-detailing. If you don't know where to start with paper models, this is a good place.