Space Elevator

"Ron Wanttaja" wrote in message
...
Space Elevators are obvious, but how does a Space Trim Tab work? :-)

Ron Wanttaja

I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing the
spaceship to altitude. If not, Google for "Eclipse project", NASA, and
perhaps F106.

They towed an idling F106 behind a C141 as a proof of concept project.

Second, you should be aware of the "payout winches" used to ground launch
hang gliders. These just pay the line out at a constant tension, rather
than reeling them in at a high rate of speed, as in sailplane launches.

So here's the scheme:
You build a tow plane about the size of a 747. The payout winch is mounted
such that it "pays out" from the CG of the airplane, on top. You have
somewhere around 100,000 lbs of Vectran tow rope (several tens of
kilometers) on the payout device. This is within the cargo capability of a
747, though you may want to throw on a couple of extra engines because of
the additional drag.

The spacecraft has a CG hook on the bottom.

You take off, and climb as high as you can, while paying out the tow line.
The spacecraft pilot basically controls the pay out. Pitch up, and a little
more line pays out. Pitch down, and it stops.

If the spacecraft can maintain a 45 degree angle behind the towplane, it
will be 70% of the towrope's length higher than the towplane.

At some point, the true airspeed of the tow plane will not provide enough
airspeed for the spacecraft to continue to climb. So the towplane starts to
turn, and the spacecraft maneuvers to the outside of the turn. Now it's
just like playing "crack the whip". The air-breathing booster is down in
the (relatively speaking) thick atmosphere at 50,000 feet, while the
spacecraft is above most of the atmosphere at say, 100,000 feet.

That's when the spacecraft releases and fires its rockets.
Because the atmosphere is so much thinner, and the spacecraft is going
faster than it would be at lower altitudes, the increase in peak altitude
achievable should be much higher than just the 50,000 ft altitude difference
between the tow plane and the spacecraft.

After the spacecraft releases, the towplane also releases the towline, and
it descends under a parachute, separately.

There, I feel better.

Tim Ward

You should post this on sci.space.tech

It is a moderated news group and the signal to nise ration is high.





im Ward" wrote:


"Ron Wanttaja" wrote in message
.. .
Space Elevators are obvious, but how does a Space Trim Tab work? :-)

Ron Wanttaja

I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing the
spaceship to altitude. If not, Google for "Eclipse project", NASA, and
perhaps F106.

They towed an idling F106 behind a C141 as a proof of concept project.

Second, you should be aware of the "payout winches" used to ground launch
hang gliders. These just pay the line out at a constant tension, rather
than reeling them in at a high rate of speed, as in sailplane launches.

So here's the scheme:
You build a tow plane about the size of a 747. The payout winch is mounted
such that it "pays out" from the CG of the airplane, on top. You have
somewhere around 100,000 lbs of Vectran tow rope (several tens of
kilometers) on the payout device. This is within the cargo capability of a
747, though you may want to throw on a couple of extra engines because of
the additional drag.

The spacecraft has a CG hook on the bottom.

You take off, and climb as high as you can, while paying out the tow line.
The spacecraft pilot basically controls the pay out. Pitch up, and a little
more line pays out. Pitch down, and it stops.

If the spacecraft can maintain a 45 degree angle behind the towplane, it
will be 70% of the towrope's length higher than the towplane.

At some point, the true airspeed of the tow plane will not provide enough
airspeed for the spacecraft to continue to climb. So the towplane starts to
turn, and the spacecraft maneuvers to the outside of the turn. Now it's
just like playing "crack the whip". The air-breathing booster is down in
the (relatively speaking) thick atmosphere at 50,000 feet, while the
spacecraft is above most of the atmosphere at say, 100,000 feet.

That's when the spacecraft releases and fires its rockets.
Because the atmosphere is so much thinner, and the spacecraft is going
faster than it would be at lower altitudes, the increase in peak altitude
achievable should be much higher than just the 50,000 ft altitude difference
between the tow plane and the spacecraft.

After the spacecraft releases, the towplane also releases the towline, and
it descends under a parachute, separately.

There, I feel better.

Tim Ward

"Tim Ward" wrote in message
...

"Ron Wanttaja" wrote in message
...
Space Elevators are obvious, but how does a Space Trim Tab work? :-)

Ron Wanttaja

I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing the
spaceship to altitude. If not, Google for "Eclipse project", NASA, and
perhaps F106.

Snip

Why not resurrect project Orion and ride the wake of nuclear blasts into
space.

Tony

"Anthony" wrote in message
...

"Tim Ward" wrote in message
...

"Ron Wanttaja" wrote in message
...
Space Elevators are obvious, but how does a Space Trim Tab work? :-)

Ron Wanttaja

I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing
the
spaceship to altitude. If not, Google for "Eclipse project", NASA, and
perhaps F106.

Snip

Why not resurrect project Orion and ride the wake of nuclear blasts into
space.

Tony

Cost?
Even if the hardware was free, the infrastructure to support a surface
launch would be awfully expensive. I know Niven & Pournelle had something
like that in Lucifer's Hammer, but that was an effort to throw off alien
conquerors.

I thought Orion was space-to-space transportation.

The system I've proposed wouldn't be cheap, but it could conceivably take
off and land from a regular airport.

Tim Ward

"Tim Ward" wrote in message
...

I know Niven & Pournelle had something
like that in Lucifer's Hammer, but that was an effort to throw off
alien
conquerors.

The book was "Footfall", not "Lucifer's Hammer". In the fictional
account, the city of Bellingham WA was scragged by the Orion-engined
takeoff.

BTW, "Orion spacevehicle" and "aviation.homebuilt" are not a close
match. ;-)

On Sun, 27 Jun 2004 01:32:51 GMT, "Felger Carbon"
wrote:

"Tim Ward" wrote in message
...

I know Niven & Pournelle had something
like that in Lucifer's Hammer, but that was an effort to throw off
alien
conquerors.

The book was "Footfall", not "Lucifer's Hammer". In the fictional
account, the city of Bellingham WA was scragged by the Orion-engined
takeoff.

Jerry later said that, had he known what the future would bring, they
would have chosen Redmond. :-)


BTW, "Orion spacevehicle" and "aviation.homebuilt" are not a close
match. ;-)



I've seen video of a proof of concept vehicle. Esentially a large
hemispherical plate of steel, maybe 200 kilos. They had some sort of
device to load the explosives into the fireing chamber. They used
half sticks of dynamite and lofted it to over 1000 feet. Really quite
impressive, although I think RUN would be the order of the day when it
quit being a flying machine and turned into a heavy slab of metal.
--
dillon

When I was a kid, I thought the angel's name was Hark
and the horse's name was Bob.

"Tim Ward" wrote in message
...

Why not resurrect project Orion and ride the wake of nuclear blasts into
space.

Tony

Cost?
Even if the hardware was free, the infrastructure to support a surface
launch would be awfully expensive. I know Niven & Pournelle had something
like that in Lucifer's Hammer, but that was an effort to throw off alien
conquerors.

I thought Orion was space-to-space transportation.

The system I've proposed wouldn't be cheap, but it could conceivably take
off and land from a regular airport.

Tim Ward

You really need to see the history channel show on Project Orion. I can't
do it justice here. The team on the project expected to be to Mars buy 1965
if their funding hadn't been dropped.

Tony

On Sun, 27 Jun 2004 05:38:59 +0000, Anthony wrote:


"Tim Ward" wrote in message
...

Why not resurrect project Orion and ride the wake of nuclear blasts into
space.

Tony

Cost?
Even if the hardware was free, the infrastructure to support a surface
launch would be awfully expensive. I know Niven & Pournelle had something
like that in Lucifer's Hammer, but that was an effort to throw off alien
conquerors.

I thought Orion was space-to-space transportation.

The system I've proposed wouldn't be cheap, but it could conceivably take
off and land from a regular airport.

Tim Ward

You really need to see the history channel show on Project Orion. I can't
do it justice here. The team on the project expected to be to Mars buy 1965
if their funding hadn't been dropped.

There's a good book on it by Dyson too.

AC

"Tim Ward" wrote

I dunno, but this seems as good a time as any to bring up a stupid,
complicated idea of mine for access to space.

First, you should be familiar with the Kelly Aerospace idea of towing the
spaceship to altitude. If not, Google for "Eclipse project", NASA, and
perhaps F106.

They towed an idling F106 behind a C141 as a proof of concept project.

Second, you should be aware of the "payout winches" used to ground launch
hang gliders. These just pay the line out at a constant tension, rather
than reeling them in at a high rate of speed, as in sailplane launches.

So here's the scheme:
You build a tow plane about the size of a 747. The payout winch is mounted
such that it "pays out" from the CG of the airplane, on top. You have
somewhere around 100,000 lbs of Vectran tow rope (several tens of
kilometers) on the payout device. This is within the cargo capability of a
747, though you may want to throw on a couple of extra engines because of
the additional drag.

Pac sez:
I like this idea. A 747-200F can carry 250,000 lbs of fuel and 250,000
of cargo at the same time. But at that weight 820,000 lbs it could
only make ~FL280. It would have to leave most of the gas behind: no
sweat there. Since it burns a rough average of 25,000 lbs an hour a
t/o fuel load could be as low as around ~50,000lbs of fuel for
twenty-nine minutes of ascent plus return and skinny reserves so, you
would have good rate of climb to the service ceiling of FL450 (45,000
ft.) The combined tow weight of OrbitOne plus fuel and Colonauts
could be easily be greater than 200,000 lbs if all your tow apparatus
could handle it. So figure a total Mojave t/o weight of ~650,000lbs.
These numbers are off the top of my head, I could look up the exact
ones if you want me to. Don't know if this would be cheaper than a
Vandenberg launch, but Rutan would control it all, and stay away from
gov turd interference. **** I like it. You should email this idea to
Scaled Composites Tim. Bet you a nickle Burt is already considering
it. Evergreen in Oregon is already using 74's for fire fighting.
This might be the next great role for that old queen of the sky.

pacplyer


The spacecraft has a CG hook on the bottom.

You take off, and climb as high as you can, while paying out the tow line.
The spacecraft pilot basically controls the pay out. Pitch up, and a little
more line pays out. Pitch down, and it stops.

If the spacecraft can maintain a 45 degree angle behind the towplane, it
will be 70% of the towrope's length higher than the towplane.

At some point, the true airspeed of the tow plane will not provide enough
airspeed for the spacecraft to continue to climb. So the towplane starts to
turn, and the spacecraft maneuvers to the outside of the turn. Now it's
just like playing "crack the whip". The air-breathing booster is down in
the (relatively speaking) thick atmosphere at 50,000 feet, while the
spacecraft is above most of the atmosphere at say, 100,000 feet.

That's when the spacecraft releases and fires its rockets.
Because the atmosphere is so much thinner, and the spacecraft is going
faster than it would be at lower altitudes, the increase in peak altitude
achievable should be much higher than just the 50,000 ft altitude difference
between the tow plane and the spacecraft.

After the spacecraft releases, the towplane also releases the towline, and
it descends under a parachute, separately.

There, I feel better.

Tim Ward

p.s. I wonder what Dr. "Moonraker" (Ron W.) thinks of this idea? Too
revolutionary? Not expensive enough? ;-)

pac

"pacplyer" wrote in message
om...
snippage
Pac sez:
I like this idea. A 747-200F can carry 250,000 lbs of fuel and 250,000
of cargo at the same time. But at that weight 820,000 lbs it could
only make ~FL280. It would have to leave most of the gas behind: no
sweat there. Since it burns a rough average of 25,000 lbs an hour a
t/o fuel load could be as low as around ~50,000lbs of fuel for
twenty-nine minutes of ascent plus return and skinny reserves so, you
would have good rate of climb to the service ceiling of FL450 (45,000
ft.) The combined tow weight of OrbitOne plus fuel and Colonauts
could be easily be greater than 200,000 lbs if all your tow apparatus
could handle it. So figure a total Mojave t/o weight of ~650,000lbs.
These numbers are off the top of my head, I could look up the exact
ones if you want me to. Don't know if this would be cheaper than a
Vandenberg launch, but Rutan would control it all, and stay away from
gov turd interference. **** I like it. You should email this idea to
Scaled Composites Tim. Bet you a nickle Burt is already considering
it. Evergreen in Oregon is already using 74's for fire fighting.
This might be the next great role for that old queen of the sky.

pacplyer


I think the mission might turn out to be longer than a thirty minute climb.
It's going to take some time to pay out all that tow line -- payout winch
launches are slower than auto tows, and much slower than regular winch
launches.
OTOH, the tow plane doesn't have to _lift_ the spacecraft -- it just has to
overcome the drag.
In fact, once the spacecraft is in high tow, it should be pulling up and
back (or up and out, in the slingshot portion of the flight). If things are
going right, in high tow, the spacecraft is always lifting the weight of the
tow cable that's extended, so as the tow line gets longer, the payload that
the 747's wing is lifting gets smaller. At peak altitude, the 747's wing
should only "see" the remaining fuel as a load. If the tow cable is pulling
down, then you haven't got enough tension in the tow cable. If you can't
increase the tension, then you've got too much line out.
But I expect the drag is going to be considerably higher than a stock 747.
20 km of cable an inch or so in diameter is going to be quite a bit of drag,
even at altitude. Thus my suggestion that some more engines (and higher
fuel burn) might be in order. Or do you need to throttle back a 747 at
altitude to keep the speed in limits?

I'm sure that after the publicity of the SpaceShip1 flight, Rutan is getting
all the hare-brained ideas that he can use via email, snail mail and
telephone. As I mentioned in the first post, Kelly Aerospace is working on
a tow-to-altitude and launch scheme, so some of the idea isn't new, anyway.

I wonder about the flight dynamics of a 20 km tether. I don't think anyone
has modeled anything like that. Why would they?

But a reusable 747 "first stage" that could get the "second stage" to
100,000 feet, albeit only at a little below Mach 1 (I think the drag would
go WAY up if the tether went supersonic!) is certainly cool to think about.

Tim Ward