Towards routine, reusable space launch.

On 6/16/2018 8:54 AM, Alain Fournier wrote:
On Jun/15/2018 at 11:34 PM, Fred J. McCall wrote :
JF Mezei wrote on Fri, 15 Jun 2018
22:13:01 -0400:

On 2018-06-15 19:21, Alain Fournier wrote:

Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials in the
future, maybe an elevator will become more practical,


Apart from lifting geostationary satellites to just below orbit and then
let them use their own thrusters to position to their assigned
slot/longitude, what other use would a space elevator have ?


You go above the GEO point on the cable and get flung on
interplanetary trajectories.

Yes!

You would also likely put at least one cable above GEO rotating in a
plane perpendicular to the main cable. So you can give an extra push for
interplanetary trajectories and to fine tune in which direction you
depart for said trajectories.

You can also jump off at an altitude of about 15000 km (that figure is
from the top of my head, it might be more or might be less). From there
after a few passes of aero-braking you can reach LEO with very small
thrusters.

For polar orbits, you use the rotating cable above GEO mentioned above.
But instead of using it for extra push you get off while it is
subtracting some speed but not quite in the direction of rotation of the
cable. So you subtract some speed in the direction of rotation of the
cable and give some speed in the north-south axis. You then use
aero-braking again to lower apogee, and a small thruster to raise
perigee. Note however that using the elevator to reach polar orbits in
this way isn't obvious. You would want a long and fast rotating cable
and you would want it far above GEO, it might not be practical to do so.

Building an elevator, with current technologies, is outrageously
expensive. But if you have one, it can be very useful.


we don't have one, and never will. It is a joke among Engineers.

What would is the monthly insurance payment for it? if it fell over ?

how many miles would the top swing back and forth ?

How much sideways force is pushed on it by a 20 mph wind ?

how much does one guy wire weigh ? (assume 20,000 km elevator height)

how much does one copper cable weigh if moving 200 amps ?

What voltage is needed at the ground to feed the copper wires ? assume
500 V AC needed at the top.

How much does the tower weigh counting only the copper wires, main
cable, and guy wires ?


Alain Fournier

At least three observatories with seven telescopes in active use will
be surprised to learn [that making a 6.5-m primary mirror is impossible]

That should have been five observatories and ten telescopes. I
forgot some. I won't swear I'm not still forgetting others.

In article ,
Fred J. McCall writes:
You can do things with earthbound scopes that you cannot do with
something you're going to shoot into space.

How does that apply to the current discussion? Launching a 6.5-m
mirror monolithic should in principle be easier than having the same
size mirror deploy to the required precision. The problem is making
it fit into the payload fairing.

I wouldn't be surprised if there are "black" programs with the
same difficulty.

Nope. They use a mirror roughly the size of Hubble's.

The ones we know about used mirrors that size. Anyone who actually
knows the current situation -- I don't -- wouldn't be allowed to say.

Remember, they're looking at something relatively close as such
things go.

6.5-m mirrors would have advantages over smaller ones. (I don't see
what distance has to do with anything.) I've seen hints that some
have been built and deployed, but that may be salemanship. Companies
vying for the JWST contract would have had an incentive to drop such
hints whether true or not.

The point is that a balloon does NOT replace a 'first stage'.

We agree on that.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On Jun/18/2018 at 2:45 PM, Sergio wrote :
On 6/16/2018 8:54 AM, Alain Fournier wrote:
On Jun/15/2018 at 11:34 PM, Fred J. McCall wrote :
JF Mezei wrote on Fri, 15 Jun 2018
22:13:01 -0400:

On 2018-06-15 19:21, Alain Fournier wrote:

Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials in the
future, maybe an elevator will become more practical,


Apart from lifting geostationary satellites to just below orbit and then
let them use their own thrusters to position to their assigned
slot/longitude, what other use would a space elevator have ?


You go above the GEO point on the cable and get flung on
interplanetary trajectories.

Yes!

You would also likely put at least one cable above GEO rotating in a
plane perpendicular to the main cable. So you can give an extra push for
interplanetary trajectories and to fine tune in which direction you
depart for said trajectories.

You can also jump off at an altitude of about 15000 km (that figure is
from the top of my head, it might be more or might be less). From there
after a few passes of aero-braking you can reach LEO with very small
thrusters.

For polar orbits, you use the rotating cable above GEO mentioned above.
But instead of using it for extra push you get off while it is
subtracting some speed but not quite in the direction of rotation of the
cable. So you subtract some speed in the direction of rotation of the
cable and give some speed in the north-south axis. You then use
aero-braking again to lower apogee, and a small thruster to raise
perigee. Note however that using the elevator to reach polar orbits in
this way isn't obvious. You would want a long and fast rotating cable
and you would want it far above GEO, it might not be practical to do so.

Building an elevator, with current technologies, is outrageously
expensive. But if you have one, it can be very useful.


we don't have one, and never will. It is a joke among Engineers.

What would is the monthly insurance payment for it? if it fell over ?

You put the cable on an east coast. You also put a system to cut the
cable at something like 10000 km high. If the cable breaks below that
10000 km the upper part doesn't fall it goes up, the bottom part falls
in the ocean, where it isn't likely to cause damage. If the cable breaks
higher than 10000 km, you cut it at 10000 km, the bottom 10000 km falls
once again in the ocean. The two other parts won't fall to the ground,
the lower part will probably be in an elliptical orbit, the higher part
might be in an escape trajectory. So the damage from a cable breaking
doesn't have to be high. It might be a little difficult to explain that
to an insurance company, but if you can pay for the cable, you should be
able to cover the damages.

how many miles would the top swing back and forth ?

Why do you care?

How much sideways force is pushed on it by a 20 mph wind ?

Why do you care?

how much does one guy wire weigh ? (assume 20,000 km elevator height)

Why would you put a guy wire? Don't assume 20,000 km elevator height,
assume 70,000 km, you want the top of the cable to pull up the bottom of
the cable, so you have to go beyond GEO height.

how much does one copper cable weigh if moving 200 amps ?

Don't put a copper cable. Send energy to the climber using some kind of
beamed energy. (A laser on the ground, maybe another one in
geosynchronous orbit, and photocells on the climber to convert back to
electricity. Or something of that kind.)

What voltage is needed at the ground to feed the copper wires ? assume
500 V AC needed at the top.

How much does the tower weigh counting only the copper wires, main
cable, and guy wires ?

The copper wires and guy wires are nonexistent and therefore weigh
nothing. As for the main cable, it weighs way too much. That is why I
said in the message to which you are replying that "Building an
elevator, with current technologies, is outrageously expensive." I don't
think we will ever have one.


Alain Fournier

JF Mezei wrote on Mon, 18 Jun 2018
14:27:11 -0400:

On 2018-06-18 03:05, Fred J. McCall wrote:

You also claimed that what they built and tested wasn't representative
of what they intend to build as a final article and fly, which is just
a stupid assertion.


I did no such thing. I claimed that it was not necessarily what the
final would be because during testing, they discovery problems that
require changes.


Of course you did. You said that they built their test tank out of
existing resins using existing processes but that would not be what
they built the 'real' tank using.



Just because they only told you about two tests doesn't mean they
didn't do any others.


And just because of that, you can't claim they performed those tests
succesfully either.

My point is that you can't claim "mission accomplished" on those tanks
just because of 2 tests that SpaceX chose to make public.


They've made more than two of them public. Your perpetual
underinformed state is your personal problem.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson

(Steve Willner) wrote on Mon, 18 Jun 2018
20:36:35 -0000 (UTC):

At least three observatories with seven telescopes in active use will
be surprised to learn [that making a 6.5-m primary mirror is impossible]

That should have been five observatories and ten telescopes. I
forgot some. I won't swear I'm not still forgetting others.


And you're still talking about earthbound scopes.

In article ,
Fred J. McCall writes:
You can do things with earthbound scopes that you cannot do with
something you're going to shoot into space.

How does that apply to the current discussion? Launching a 6.5-m
mirror monolithic should in principle be easier than having the same
size mirror deploy to the required precision. The problem is making
it fit into the payload fairing.


Oversize fairings are easy.

I wouldn't be surprised if there are "black" programs with the
same difficulty.

Nope. They use a mirror roughly the size of Hubble's.

The ones we know about used mirrors that size. Anyone who actually
knows the current situation -- I don't -- wouldn't be allowed to say.


Of course they're allowed to say. You can see the bloody things from
Earth, after all. Past a certain point a bigger mirror doesn't help
you for Earth observation. Atmosphere speckle becomes the driving
parameter and a bigger mirror doesn't help that.



Remember, they're looking at something relatively close as such
things go.


6.5-m mirrors would have advantages over smaller ones.


No, they wouldn't. The next generation of recce satellites will use a
mirror right around 2.4 meters; the same size used since KH-11.


(I don't see
what distance has to do with anything.) I've seen hints that some
have been built and deployed, but that may be salemanship. Companies
vying for the JWST contract would have had an incentive to drop such
hints whether true or not.


Don't let them kid you. Distance has a lot to do with everything when
it comes to telescopes.

The point is that a balloon does NOT replace a 'first stage'.

We agree on that.

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

Alain Fournier wrote on Mon, 18 Jun 2018
21:06:46 -0400:


You put the cable on an east coast.


Uh, do you mean west coast? If the thing falls isn't it going to lay
out along the direction of spin, which means it falls to the west.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden

On 6/18/2018 8:06 PM, Alain Fournier wrote:
On Jun/18/2018 at 2:45 PM, Sergio wrote :
On 6/16/2018 8:54 AM, Alain Fournier wrote:
On Jun/15/2018 at 11:34 PM, Fred J. McCall wrote :
JF Mezei wrote on Fri, 15 Jun 2018
22:13:01 -0400:

On 2018-06-15 19:21, Alain Fournier wrote:

Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials
in the
future, maybe an elevator will become more practical,


Apart from lifting geostationary satellites to just below orbit and
then
let them use their own thrusters to position to their assigned
slot/longitude, what other use would a space elevator have ?


You go above the GEO point on the cable and get flung on
interplanetary trajectories.

Yes!

You would also likely put at least one cable above GEO rotating in a
plane perpendicular to the main cable. So you can give an extra push for
interplanetary trajectories and to fine tune in which direction you
depart for said trajectories.

You can also jump off at an altitude of about 15000 km (that figure is
from the top of my head, it might be more or might be less). From there
after a few passes of aero-braking you can reach LEO with very small
thrusters.

For polar orbits, you use the rotating cable above GEO mentioned above.
But instead of using it for extra push you get off while it is
subtracting some speed but not quite in the direction of rotation of the
cable. So you subtract some speed in the direction of rotation of the
cable and give some speed in the north-south axis. You then use
aero-braking again to lower apogee, and a small thruster to raise
perigee. Note however that using the elevator to reach polar orbits in
this way isn't obvious. You would want a long and fast rotating cable
and you would want it far above GEO, it might not be practical to do so.

Building an elevator, with current technologies, is outrageously
expensive. But if you have one, it can be very useful.


we don't have one, and never will.Â* It is a joke among Engineers.

What would is the monthly insurance payment for it?Â* if it fell over ?

You put the cable on an east coast. You also put a system to cut the
cable at something like 10000 km high. If the cable breaks below that
10000 km the upper part doesn't fall it goes up, the bottom part falls
in the ocean, where it isn't likely to cause damage. If the cable breaks
higher than 10000 km, you cut it at 10000 km, the bottom 10000 km falls
once again in the ocean. The two other parts won't fall to the ground,
the lower part will probably be in an elliptical orbit, the higher part
might be in an escape trajectory. So the damage from a cable breaking
doesn't have to be high. It might be a little difficult to explain that
to an insurance company, but if you can pay for the cable, you should be
able to cover the damages.

how much does 10,000 of cable weigh? 100,000 #
the center of gravity is directly over the support, so you have 100,000#
of steel cable crashing onto it.

nothing will go into orbit as the accelleration vector is stright down,
gravity.


how many miles would the top swing back and forth ?

Why do you care?

I asking to see if you know what you are talking about. 20,000 km is
12,427 miles, if you support the tower it will swing at least 2 degrees
sin 2 degrees = 0.035 times 12427 = *434 miles*

does the tip swinging wider than most states bother you ??


How much sideways force is pushed on it by a 20 mph wind ?

Why do you care?

....to evaporate your imagination with facts.



how much does one guy wire weigh ? (assume 20,000 km elevator height)

Why would you put a guy wire? Don't assume 20,000 km elevator height,
assume 70,000 km, you want the top of the cable to pull up the bottom of
the cable, so you have to go beyond GEO height.

so what is the weight of 70,000 km of cable to support 500# ?

[there is no cable that will support itself 70,000 km, darling)



how much does one copper cable weigh if moving 200 amps ?

Don't put a copper cable. Send energy to the climber using some kind of
beamed energy. (A laser on the ground, maybe another one in
geosynchronous orbit, and photocells on the climber to convert back to
electricity. Or something of that kind.)

Use McGinn's patented plasma's and water vapor it up. What happens
when you use a 1000 watt laser to shoot power to it ? the beam heats up
the air and defocuses the beam and the power splinters out, the power
does not get there.

there is no know laser that can meet the dispersion requirements either
(google dispersion laser)


What voltage is needed at the ground to feed the copper wires ?Â* assume
500 V AC needed at the top.

How much does the tower weigh counting only the copper wires, main
cable, and guy wires ?

The copper wires and guy wires are nonexistent and therefore weigh
nothing. As for the main cable, it weighs way too much. That is why I
said in the message to which you are replying that "Building an
elevator, with current technologies, is outrageously expensive." I don't
think we will ever have one.

it is joke bate by Engineers,



Alain Fournier

Sergio wrote on Mon, 18 Jun 2018 22:17:21 -0500:

On 6/18/2018 8:06 PM, Alain Fournier wrote:
On Jun/18/2018 at 2:45 PM, Sergio wrote :
On 6/16/2018 8:54 AM, Alain Fournier wrote:
On Jun/15/2018 at 11:34 PM, Fred J. McCall wrote :
JF Mezei wrote on Fri, 15 Jun 2018
22:13:01 -0400:

On 2018-06-15 19:21, Alain Fournier wrote:

Yes. But I think I am a little less optimistic than you about it
becoming practical in the future. If we have fantastic materials
in the
future, maybe an elevator will become more practical,


Apart from lifting geostationary satellites to just below orbit and
then
let them use their own thrusters to position to their assigned
slot/longitude, what other use would a space elevator have ?


You go above the GEO point on the cable and get flung on
interplanetary trajectories.

Yes!

You would also likely put at least one cable above GEO rotating in a
plane perpendicular to the main cable. So you can give an extra push for
interplanetary trajectories and to fine tune in which direction you
depart for said trajectories.

You can also jump off at an altitude of about 15000 km (that figure is
from the top of my head, it might be more or might be less). From there
after a few passes of aero-braking you can reach LEO with very small
thrusters.

For polar orbits, you use the rotating cable above GEO mentioned above.
But instead of using it for extra push you get off while it is
subtracting some speed but not quite in the direction of rotation of the
cable. So you subtract some speed in the direction of rotation of the
cable and give some speed in the north-south axis. You then use
aero-braking again to lower apogee, and a small thruster to raise
perigee. Note however that using the elevator to reach polar orbits in
this way isn't obvious. You would want a long and fast rotating cable
and you would want it far above GEO, it might not be practical to do so.

Building an elevator, with current technologies, is outrageously
expensive. But if you have one, it can be very useful.


we don't have one, and never will.* It is a joke among Engineers.

What would is the monthly insurance payment for it?* if it fell over ?

You put the cable on an east coast. You also put a system to cut the
cable at something like 10000 km high. If the cable breaks below that
10000 km the upper part doesn't fall it goes up, the bottom part falls
in the ocean, where it isn't likely to cause damage. If the cable breaks
higher than 10000 km, you cut it at 10000 km, the bottom 10000 km falls
once again in the ocean. The two other parts won't fall to the ground,
the lower part will probably be in an elliptical orbit, the higher part
might be in an escape trajectory. So the damage from a cable breaking
doesn't have to be high. It might be a little difficult to explain that
to an insurance company, but if you can pay for the cable, you should be
able to cover the damages.


how much does 10,000 of cable weigh? 100,000 #
the center of gravity is directly over the support, so you have 100,000#
of steel cable crashing onto it.


Nope. The Earth spins, you know. And STEEL? That's cute.


nothing will go into orbit as the accelleration vector is stright down,
gravity.


Well, no. When whole, the cable is under tension, not compression.
Remove weight from the bottom or break the tether point and it goes UP
above the break, not down.



how many miles would the top swing back and forth ?

Why do you care?


I asking to see if you know what you are talking about. 20,000 km is
12,427 miles, if you support the tower it will swing at least 2 degrees
sin 2 degrees = 0.035 times 12427 = *434 miles*

does the tip swinging wider than most states bother you ??


You're not smart enough to be asking questions. It's not a 'tower'.


How much sideways force is pushed on it by a 20 mph wind ?

Why do you care?

...to evaporate your imagination with facts.


That would be refreshing. When are you going to start?



how much does one guy wire weigh ? (assume 20,000 km elevator height)

Why would you put a guy wire? Don't assume 20,000 km elevator height,
assume 70,000 km, you want the top of the cable to pull up the bottom of
the cable, so you have to go beyond GEO height.

so what is the weight of 70,000 km of cable to support 500# ?


That rather depends on what it's made of.


[there is no cable that will support itself 70,000 km, darling)


There is no cable that will support its own weight like that YET. You
really need to STFU until you educate yourself.



how much does one copper cable weigh if moving 200 amps ?

Don't put a copper cable. Send energy to the climber using some kind of
beamed energy. (A laser on the ground, maybe another one in
geosynchronous orbit, and photocells on the climber to convert back to
electricity. Or something of that kind.)

Use McGinn's patented plasma's and water vapor it up. What happens
when you use a 1000 watt laser to shoot power to it ? the beam heats up
the air and defocuses the beam and the power splinters out, the power
does not get there.

there is no know laser that can meet the dispersion requirements either
(google dispersion laser)


Hogwash.


What voltage is needed at the ground to feed the copper wires ?* assume
500 V AC needed at the top.

How much does the tower weigh counting only the copper wires, main
cable, and guy wires ?

The copper wires and guy wires are nonexistent and therefore weigh
nothing. As for the main cable, it weighs way too much. That is why I
said in the message to which you are replying that "Building an
elevator, with current technologies, is outrageously expensive." I don't
think we will ever have one.

it is joke bate by Engineers,


You wouldn't know an engineer if you tripped over one.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson

Sergio schrieb:
On 6/16/2018 8:54 AM, Alain Fournier wrote:

Building an elevator, with current technologies, is outrageously
expensive. But if you have one, it can be very useful.


we don't have one, and never will. It is a joke among Engineers.

Well, I did like the space elevator in "Red Mars".

Spoiler:

When it fell, Mars finally acquired a visible equator... it came
down as some sort of continuous meteor.

In article , Sergio wrote:
how about a Space Slingshot ?

Do you mean a rotating skyhook?

Some of those ideas are ... intriguing. And have much less
stringent requirements on materials.

--
Mike Van Pelt | "I don't advise it unless you're nuts."
mvp at calweb.com | -- Ray Wilkinson, after riding out Hurricane
KE6BVH | Ike on Surfside Beach in Galveston