StarRider1701":20qjhiky said:
1. 60% of the mass provides 80(or more)% of the lift. Clearly the solid fuel boosters do more than just barely lift thier own mass. Yes you have to fire more than 2, my proposal calls for firing 4 as the first stage rockets, then firing the final 2 as the second stage thrust to get it into orbit.
2. Never said anything about shutting them off prematurely.
3. For directional control, small, light fins can be added to the normal two boosters, on either side of the tank.
Yes, for the small amount that each shuttle can carry, it would be prohibitively costly, that is why I'm making this suggestion. As for "long term hydrogen storage" I did suggest launching the shuttle a few hours after the tank, so that long term is not an issue.
Did you even read my idea before making up your senseless ********, most of which didn't even relate to my idea?
Yes, StarRider1701, I read your idea very carefully,
several times.
Basically as proposed, you have a huge unguided (without the fins
you just mentioned, and a guidence system of some sort) tank of LOX and Hydrogen being launched (and I have doubts about even 4 SRBs being enough, remember it is not additive, you have to take off the additional mass for each one from the initial launch capability).
To detail the numbers:
"Each SRB weighs approximately 1,300,000 lb (590,000 kg) at launch"
"Each booster has a liftoff thrust of approximately 2,800,000 pounds-force"
http://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster
11,200,000 liftoff pounds-force for 4 SRBs
-7,800,000 liftoff weight of 6 SRBs
-1,680,000 liftoff weight of full tank
=1,720,000 or, a little over half the thrust of a single SRB
Add anything for your fins, guidence, and additional structure and reinforcement that would be necessary for the added SRBs, and it looks pretty iffy.
In addition, you would have no control (hence #2) over shutting down the engines once you achieved
a desired orbit which is why even Aries I had a liquid propelled 2nd stage. This is necessary so that your Shuttle could rendevous with it. Simply launching it ballistically wouldn't cut it. Too much and your orbit is too high and maybe beyond the Shuttle's operational altitude, too little and we would have complaints from Europe about this huge thing landing on someone (and it would make the Hindenberg look like a firecracker). The SRBs are fine tuned for 1 task in one configuration. Adjusting a solid fuel rocket is not that easy, it burns the whole length of the tube.
And yes, I did skip over the Shuttle launch shortly after (sorry bout that). The reference to
"long term hydrogen storage"
was tied to the NASA study below anyway, they didn't think of it at that time.
I think the study NASA originally did pretty much details the problems of such an approach, excluding the hydrogen storage issue.
http://beyondapollo.blogspot.com/2009/11/cislunar-shuttle-orbiter-1971.html
All that being siad, please do your research, put your numbers together, and justify your hypothesis.
There is really no practical value to sending an Orbiter to the moon vs a custom built, stripped down for economy, spacecraft that would require far less fuel and be far less expensive. It needn't be much more than a crew capsule, life support, tanks and engines, all tied together with as little framework as you can get by with. If you are gonna launch fuel, send up a whole lot less, a whole lot cheaper, and fuel the aforementioned spacecraft.