Balloons to launch shuttle ?

From purely an energy budget point of view,

Suppose the shuttle (or CEV) were to be lifted by a giant balloon to say
60,000 feet before being released and igniting its engines...


By launching the shuttle from say 60,000 feet, would the actual altitude
gain as well as avoiding the acceleration through the denser atmosphere
end up saving a significant amount of energy ? Or would it be trivially
small compared to the total energy budget ?

Would launching from 60,000 feet also greatly reduce any of the tank
problems with regards to air resistance breaking pieces of foam off ?


Also in such a launch, could the current shuttle ignite its engines from
a mostly horizontal position and provide enough lift/steering to
accelerate without falling down too much ?

John Doe wrote:
From purely an energy budget point of view,

Suppose the shuttle (or CEV) were to be lifted by a giant balloon to say
60,000 feet before being released and igniting its engines...


By launching the shuttle from say 60,000 feet, would the actual altitude
gain as well as avoiding the acceleration through the denser atmosphere
end up saving a significant amount of energy ? Or would it be trivially
small compared to the total energy budget ?

Would launching from 60,000 feet also greatly reduce any of the tank
problems with regards to air resistance breaking pieces of foam off ?


Also in such a launch, could the current shuttle ignite its engines from
a mostly horizontal position and provide enough lift/steering to
accelerate without falling down too much ?

Its a good idea that secretely been done. That black mini shuttle air
launched by a bigger carrier aircrat

John Doe wrote:
From purely an energy budget point of view,

Suppose the shuttle (or CEV) were to be lifted by a giant balloon to say
60,000 feet before being released and igniting its engines...


By launching the shuttle from say 60,000 feet, would the actual altitude
gain as well as avoiding the acceleration through the denser atmosphere
end up saving a significant amount of energy ? Or would it be trivially
small compared to the total energy budget ?

Would launching from 60,000 feet also greatly reduce any of the tank
problems with regards to air resistance breaking pieces of foam off ?


Also in such a launch, could the current shuttle ignite its engines from
a mostly horizontal position and provide enough lift/steering to
accelerate without falling down too much ?

QuickReach is supposed to launch from about half this altitude. The
technique is expected to save 3.5% on total delta-v. A higher altitude

launch would save a bit more. But the balloon would be a big problem.

Shuttle weighs about 2,000 tonnes at liftoff. The biggest airships
only
lifted a bit over 100 tonnes. It would take perhaps 20 Hindenburgs,
each 804 feet long and 135 feet in diameter filled with hydrogen gas,
to
lift a shuttle stack!

But to where will the balloon lift the shuttle? The wind will decide!

Not a good deal if the wind blows back on-shore!

And how does one do an abort? Lower shuttle into the Atlantic?

A drop launch requires the rocket to thrust mostly vertically during
the
initial moments. Even winged Pegasus does a rapid pull up to near
vertical after its drop-launch.

- Ed Kyle

Blimey, if you think the Earth is bad for air density, think about the
problem of doing a Sample return from Venus!

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
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"ed kyle" wrote in message
ups.com...

John Doe wrote:
From purely an energy budget point of view,

Suppose the shuttle (or CEV) were to be lifted by a giant balloon to say
60,000 feet before being released and igniting its engines...


By launching the shuttle from say 60,000 feet, would the actual altitude
gain as well as avoiding the acceleration through the denser atmosphere
end up saving a significant amount of energy ? Or would it be trivially
small compared to the total energy budget ?

Would launching from 60,000 feet also greatly reduce any of the tank
problems with regards to air resistance breaking pieces of foam off ?


Also in such a launch, could the current shuttle ignite its engines from
a mostly horizontal position and provide enough lift/steering to
accelerate without falling down too much ?

QuickReach is supposed to launch from about half this altitude. The
technique is expected to save 3.5% on total delta-v. A higher altitude

launch would save a bit more. But the balloon would be a big problem.

Shuttle weighs about 2,000 tonnes at liftoff. The biggest airships
only
lifted a bit over 100 tonnes. It would take perhaps 20 Hindenburgs,
each 804 feet long and 135 feet in diameter filled with hydrogen gas,
to
lift a shuttle stack!

But to where will the balloon lift the shuttle? The wind will decide!

Not a good deal if the wind blows back on-shore!

And how does one do an abort? Lower shuttle into the Atlantic?

A drop launch requires the rocket to thrust mostly vertically during
the
initial moments. Even winged Pegasus does a rapid pull up to near
vertical after its drop-launch.

- Ed Kyle