TSTO Spaceplane

[Eagle1Division]

If I understand correctly, I think the big advantage of an SSTO would be it's short turnaround time because no processing / attaching a second stage, etc. etc. But what if both stages had a "spaceplane" design?

Stage 1 "Mothership":
#1. Uses JP-1-fuelled turbofans to climb to their service ceiling, or to a lower altitude for shorter turbofan flight time to save fuel mass.
#2. Once at service ceiling, ignites chemical rockets for the first stage of the ascent.
#3. At rocket engine burnout, "Drops" the orbiter. Being much lighter now, it flies TAL, maybe even glides, with the assistance of a small amount of remaining JP-1 fuel for the turbofans.
#4. After landing in Europe, it refuels JP-1 and flies back to the KSC. It's able to fly trans-atlantic on turbofans alone now, because it's much lighter (not carrying the orbiter or chemical rocket fuel.)
---
Stage 2 "Orbiter":
#1. When dropped from Stage 1 "mothership", ignites it's own engines and continues to orbit. Finishes mission, lands like space shuttle.
#2. At the KSC, instead of requiring VAB assembly, it's pulled under the "mothership", and a system "docks" to the mothership. (pulled like an airplane at an airport, no heavy machinery required, takes only a few minutes. Attaches onto the mothership with a system like the doors at NORAD use to lock, except it would be the mothership "locking" to the top of the orbiter. The mothership carries the heavy equipment, saving weight on the orbiter.)

The mothership would use distended and conformal fuel tanks to help the mass ratio. ([ame=http://en.wikipedia.org/wiki/Conformal_fuel_tank]Just in case[/ame])

Questions:
#1. What's the highest mass ratio possible with an X-33/Venture-Star design, using existing materials? This would be the mass ratio of the Orbiter. Unlike the mothership, the orbiter does not need very good flight characteristics.
#2. And what is the best mass ratio that's possible while maintaining flight characteristics of a flyable aircraft, i.e., can cruise with small turbofans and a glide ratio much better than the Shuttle's.
#3. Finally, why has nobody tried this yet?

 

[Urwumpe]

The other questions would require some more research there, since they actually mean somebody else doing your engineering work on optimization problems, but on #3 I can give you a quick answer.

#3. Finally, why has nobody tried this yet?

Who has already tried this before? Ze Germans!

http://www.astronautix.com/lvs/saegerii.htm

Went actually pretty far until it was canceled, the engines had already been in tests. The cost argument at the end (only 10-30% cheaper than the Ariane 5 if you fly the same number of missions with only few vehicles), was just an excuse for the politicians.

It was pretty feasible and more economic then the Ariane 5, but not without technological risk. And this risk was nothing for politicians who just realized that the reunification of Germany costs actually money.

 

[Notebook]

Didn't get to orbit, but nearl there...

[ame="http://en.wikipedia.org/wiki/Short_Mayo_Composite"]Short Mayo Composite - Wikipedia, the free encyclopedia[/ame]

N.

 

[Eagle1Division]

The other questions would require some more research there, since they actually mean somebody else doing your engineering work on optimization problems, but on #3 I can give you a quick answer.

Hmm. Lemme be more specific.
#1. I would like to find the farthest they got with the design for the Venture Star. What Mass Ratio were they expecting?
#2. What airplane out there has the highest mass ratio / farthest range without mid-air refuelling. A little math work of mine has brought up ~3.4 as the highest mass ratio for an aircraft. Wondering if any aircraft out there has a mass ratio over 2.5 it would be good to hear about.

Too bad it was canceled, I hate how nowadays every neat space program gets canceled. I mean, what the heck? Is it just standard, or fun or something for them to cancel these awesome programs? Why don't those charismatic politicians just sweet talk some people like they enjoy doing so much instead of hurting mankind's progress...
I mean, it's like it's a freaking tradition or fun passtime for politicians to cancel space programs. They can spend tens or hundreds of billions however they feel like, whenever the feel like depending on their mood and the wind, but the progress of human civilization doesn't deserve just a few of those billions? Arrghh. (NASA less than 0.5 % of Congressional spending...)

 

[Eli13]

Yes it is sad. Well thats an understatement. I was going to post something similar to that but you took the words out of my mouth.

 

[tori]

(obligatory 2001 reference)