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Solar Sail to sink NASA?; Will the $30 m spent on new system flop
Topic Started: May 5 2005, 12:48 PM (439 Views)
JGSL
Lieutenant
Solar Sail


Okay, I just get this premonition that the expensive endevors of nasa recently might cuase a slow down in space exploration if a "success" is not deamed. But then again, with the shuttles grounded, we may just already have seen such a slow down.

I guess what I'd like to see is a continued effort in space exploration.
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Swidden
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Adm. Gadfly-at-large; Provisional wRench-fly at large
From what I understand, I believe some tests on the material in question have been run prior to the last shuttle accident or are expected to be run shortly after the shuttles fly again.

Personally, I think the sail project holds real promise for our future in space.
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Dwayne
Profanity deleted by Hoss
Swidden
May 6 2005, 11:21 PM
From what I understand, I believe some tests on the material in question have been run prior to the last shuttle accident or are expected to be run shortly after the shuttles fly again.

Personally, I think the sail project holds real promise for our future in space.

I'm increasingly skeptical of the solar sail for intra-stellar space travel, because a vehicle using only the solar sail would, with some exceptions, only have a one-way trip ->>> away from the sun.

This is not to say that there may not be some future discovery of a solar wind equivelent to the Bernoulli Effect, thus allowing a solar sail equiped vehicle to tack into the solar winds, the only other way these sails will work is by using complex vectoring maneuvers to either slow or increase the speed of the craft, thus decrease or increase the distance from the sun.

I do think that solar sails may be perfect for long distance - long duration interstellar craft where a return voyage is not expected nor needed.
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Swidden
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Adm. Gadfly-at-large; Provisional wRench-fly at large
I would not think of a solar sail for anything interstellar either. However, intra-solar might be another story all together...
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Dwayne
Profanity deleted by Hoss
Swidden
May 8 2005, 05:15 PM
I would not think of a solar sail for anything interstellar either. However, intra-solar might be another story all together...

I disagree, but to each his own.
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somerled
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Admiral MacDonald RN
No you are quite wrong.

The beauty of solar sails is that you have continous acceleration, and if the sail to ship mass ratio is high enough you can theoretically attain relativistic velocities. Something impossible with current space flight technologies as constant acceleration over a long period of time requires too much fuel mass.
One could readily design a solar sail that could provide 0.1g or higher , and any high school kid can calculate how long it would take to reach 0.1c say using Newton's Equations of Motion.

Once in deep interplanetary or interstellar space the pressure of photons on the sail will be very light so the vessel will then just cruise using its momentum to the the destination where it would decelerate with thrusters (if a planet) or use the photon pressure from the destination star to decelerate it.

There is no reason why this propulsion system needs to be a one-way. Have you ever seen sail boats sailing into the wind. (It's all to do with how the resultant force that provides the thrust is built up vectorially).
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Dwayne
Profanity deleted by Hoss
somerled
May 9 2005, 12:43 AM
blah blah blah

Maybe you should read the thread before applying your fingers to the keyboard.
Dwayne
May 8 2005, 03:58 PM
Swidden
May 6 2005, 11:21 PM
From what I understand, I believe some tests on the material in question have been run prior to the last shuttle accident or are expected to be run shortly after the shuttles fly again.

Personally, I think the sail project holds real promise for our future in space.

I'm increasingly skeptical of the solar sail for intra-stellar space travel, because a vehicle using only the solar sail would, with some exceptions, only have a one-way trip ->>> away from the sun.

This is not to say that there may not be some future discovery of a solar wind equivelent to the Bernoulli Effect, thus allowing a solar sail equiped vehicle to tack into the solar winds, the only other way these sails will work is by using complex vectoring maneuvers to either slow or increase the speed of the craft, thus decrease or increase the distance from the sun.

I do think that solar sails may be perfect for long distance - long duration interstellar craft where a return voyage is not expected nor needed.

Now, as you can see, you've said nothing new and it seems the reality is you have only ventured into this thread trolling for an argument.
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digifan2004
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Electronic genius
Base on what I had read, the solar sail experiment won't replace NASA. In fact I think it will enhance this government organization's overall mission - To explore space. It will take some time but if this experiment is successful it will be one step closer in getting Mankind into establishing a permanent presence in space.
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The Hindmost
Cadet 3rd Year
Solar sails can be very easilly used for 2 way trips to another star. But instead of using the sun as the method of propulsion, a laser would be used with a focusing lense somewhere out in the vacinity of Saturn. The actual sail itself would be built in three stages, a central sail with 2 ring shaped sails connected around it. The first sail would be disconnected and the light would reflect off it to hit the front of the ship, decellerating it. The second ring portion would be used in the same way to accelerate the ship again and send it on its way home.

the URL of the article by Robert L. Forward on this subject: http://www.planetary.org/interstellar/forward.html
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doctortobe
Speak softly, and carry a 57 megaton stick!
Why not just use the old nuke and bowl method?
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Dwayne
Profanity deleted by Hoss
^^^

You're absolutely right to consider it, but the enviromentalists think that in the vast radioactive wasteland that is space, nuclear propulsion might cause too much radioactive contamination.
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Minuet
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Fleet Admiral Assistant wRench, Chief Supper Officer
Administrative Response

Dwayne - recent events here have forced us to crack down on those that would use terminology that is insulting to large groups of people.

I ask your co-operation in using terms that are descriptive but not insulting.

End Administrative Response
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somerled
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Admiral MacDonald RN
The Hindmost
May 16 2005, 11:45 AM
Solar sails can be very easilly used for 2 way trips to another star. But instead of using the sun as the method of propulsion, a laser would be used with a focusing lense somewhere out in the vacinity of Saturn. The actual sail itself would be built in three stages, a central sail with 2 ring shaped sails connected around it. The first sail would be disconnected and the light would reflect off it to hit the front of the ship, decellerating it. The second ring portion would be used in the same way to accelerate the ship again and send it on its way home.

the URL of the article by Robert L. Forward on this subject: http://www.planetary.org/interstellar/forward.html

Interesting. Thanks for the link.
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somerled
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Admiral MacDonald RN
Dwayne
May 17 2005, 09:41 AM
^^^

You're absolutely right to consider it, but the enviromentalists think that in the vast radioactive wasteland that is space, nuclear propulsion might cause too much radioactive contamination.

More likely the crew would become lethally irradiated. And who wants nuclear weapons in space ?
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Dwayne
Profanity deleted by Hoss
somerled
May 18 2005, 07:24 AM
Dwayne
May 17 2005, 09:41 AM
^^^

You're absolutely right to consider it, but the enviromentalists think that in the vast radioactive wasteland that is space, nuclear propulsion might cause too much radioactive contamination.

More likely the crew would become lethally irradiated. And who wants nuclear weapons in space ?

Here's NASAs thinking on the subject, "Nuclear Thermal Propulsion (NTP) could enable shorter travel times to planets such as Mars, thereby reducing astronaut exposure to cosmic rays and other damaging forms of space radiation, "so a review on nuclear thermal propulsion might be in order here.

Edited to remove insulting comment - not easy with the link!
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