Pat Flannery wrote:
This is a really interesting design for a two-stage-to-orbit reusable
light satellite booster/transatmospheric hypersonic attack aircraft.
At only 123 feet in length and capable of reaching Mach 9-10, the
flyback booster packs a lot of performance into a small vehicle.
http://www.sei.aero/library/paper_ar...-2004-5950.pdf
http://www.sei.aero/library/paper_ar...50_present.pdf

That's not a serious design - it's an effort by the company to show off
/ demonstrate their optimization and analysis software and abilities.

It's also an excellent demonstration of why you don't want to use
airbreathing propulsion for large chunks of your space launch
acceleration - to get to the 9k fps staging point they incur nearly
twice that in drag losses and need about five times as much propulsion
hardware.

If you've got spare time, try putting together an excel spreadsheet,
dumping the scramjet hardware retaining only enough turbojet thrust for
flyback, and using their rocket engines for ascent. Not only does dry
weight go down, but it looks like gross weight does as well.

Of course, if you spend all of your time trying to complicate your
designs so you can get more analysis contracts, it can be difficult to
switch mental gears to "cheap, not cool" when you actually get the
opportunity to build something.

-jake