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Close Sun-orbiting mirrors for beamed propulsion and space solar power.



 
 
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  #1  
Old June 1st 17, 07:30 PM posted to rec.arts.sf.science,sci.space.policy,sci.optics,sci.physics,sci.military.naval
Robert Clark[_5_]
external usenet poster
 
Posts: 245
Default Close Sun-orbiting mirrors for beamed propulsion and space solar power.

NASA just announced a solar probe to travel quite close to the Sun, about
3.7 million miles from the solar surface:

Nasa’s hotly anticipated solar mission renamed to honour astrophysicist
Eugene Parker.
Renamed the Parker Solar Probe to honour solar astrophysicist who predicted
high speed solar wind, the spacecraft will attempt to get close to sun’s
surface.
Wednesday 31 May 2017 07.08 EDT
https://www.theguardian.com/science/...lar-probe-plus

Spacecraft able to get this close to the Sun could potentially allow beamed
interstellar propulsion. For a spacecraft of any size, you would need huge
amounts of beamed power. Where to get it? If you make the beam be
solar-powered then can just use space-borne mirrors to focus the Suns rays.
But the mirror(s) would have to be impractically large if they were in Earth
orbit.

But what if we placed them close to the Sun? At the distance quoted of 3.7
million miles away from the Sun a mirror 1 km on a side could collect a
terawatt worth of power.

Note this could also be used for space solar power when beamed towards
Earth.

Bob Clark

----------------------------------------------------------------------------------------------------------------------------------
Finally, nanotechnology can now fulfill its potential to revolutionize
21st-century technology, from the space elevator, to private, orbital
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:

Nanotech: from air to space.
https://www.indiegogo.com/projects/n...ce/x/13319568/
----------------------------------------------------------------------------------------------------------------------------------

  #2  
Old June 1st 17, 08:09 PM posted to rec.arts.sf.science,sci.space.policy,sci.optics,sci.physics,sci.military.naval
Phil Hobbs[_3_]
external usenet poster
 
Posts: 13
Default Close Sun-orbiting mirrors for beamed propulsion and space solarpower.

On 06/01/2017 02:30 PM, Robert Clark wrote:
NASA just announced a solar probe to travel quite close to the Sun,
about 3.7 million miles from the solar surface:

Nasa’s hotly anticipated solar mission renamed to honour astrophysicist
Eugene Parker.
Renamed the Parker Solar Probe to honour solar astrophysicist who
predicted high speed solar wind, the spacecraft will attempt to get
close to sun’s surface.
Wednesday 31 May 2017 07.08 EDT
https://www.theguardian.com/science/...lar-probe-plus


Spacecraft able to get this close to the Sun could potentially allow
beamed interstellar propulsion. For a spacecraft of any size, you would
need huge amounts of beamed power. Where to get it? If you make the beam
be solar-powered then can just use space-borne mirrors to focus the Suns
rays. But the mirror(s) would have to be impractically large if they
were in Earth orbit.

But what if we placed them close to the Sun? At the distance quoted of
3.7 million miles away from the Sun a mirror 1 km on a side could
collect a terawatt worth of power.

Note this could also be used for space solar power when beamed towards
Earth.

Bob Clark


Gee, what could go wrong?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
  #3  
Old June 1st 17, 09:46 PM posted to rec.arts.sf.science,sci.space.policy,sci.physics
Serg io
external usenet poster
 
Posts: 8
Default Close Sun-orbiting mirrors for beamed propulsion and space solarpower.

On 6/1/2017 1:30 PM, Robert Clark wrote:
NASA just announced a solar probe to travel quite close to the Sun,
about 3.7 million miles from the solar surface:



Spacecraft able to get this close to the Sun could potentially allow
beamed interstellar propulsion. For a spacecraft of any size, you would
need huge amounts of beamed power. Where to get it? If you make the beam
be solar-powered then can just use space-borne mirrors to focus the Suns
rays. But the mirror(s) would have to be impractically large if they
were in Earth orbit.

But what if we placed them close to the Sun? At the distance quoted of
3.7 million miles away from the Sun a mirror 1 km on a side could
collect a terawatt worth of power.

Note this could also be used for space solar power when beamed towards
Earth.


nope, dispersion, orbatal speeds, pointing, power is less than
0.0000000000000001% of total, $$$, etc, etc.


Bob Clark


  #4  
Old June 2nd 17, 07:48 PM posted to rec.arts.sf.science,sci.space.policy,sci.optics,sci.physics,sci.military.naval
Robert Clark[_5_]
external usenet poster
 
Posts: 245
Default Close Sun-orbiting mirrors for beamed propulsion and space solar power.

"Robert Clark" wrote in message news ================================================== ===============
NASA just announced a solar probe to travel quite close to the Sun, about
3.7 million miles from the solar surface:

Nasa’s hotly anticipated solar mission renamed to honour astrophysicist
Eugene Parker.
Renamed the Parker Solar Probe to honour solar astrophysicist who predicted
high speed solar wind, the spacecraft will attempt to get close to sun’s
surface.
Wednesday 31 May 2017 07.08 EDT
https://www.theguardian.com/science/...lar-probe-plus

Spacecraft able to get this close to the Sun could potentially allow beamed
interstellar propulsion. For a spacecraft of any size, you would need huge
amounts of beamed power. Where to get it? If you make the beam be
solar-powered then can just use space-borne mirrors to focus the Suns rays.
But the mirror(s) would have to be impractically large if they were in Earth
orbit.

But what if we placed them close to the Sun? At the distance quoted of 3.7
million miles away from the Sun a mirror 1 km on a side could collect a
terawatt worth of power.

Note this could also be used for space solar power when beamed towards
Earth.
================================================== ===============

What would be the size of the collector array at Earth to capture most of
the light focused from the 1 km wide mirror located at the Sun, i.e., the
size of the Airy disk at the Earth? How large at Proxima Centauri?

Bob Clark


----------------------------------------------------------------------------------------------------------------------------------
Finally, nanotechnology can now fulfill its potential to revolutionize
21st-century technology, from the space elevator, to private, orbital
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:

Nanotech: from air to space.
https://www.indiegogo.com/projects/n...ce/x/13319568/
----------------------------------------------------------------------------------------------------------------------------------

  #5  
Old June 3rd 17, 09:55 AM posted to sci.space.policy,sci.optics
Niels Jørgen Kruse[_2_]
external usenet poster
 
Posts: 23
Default Close Sun-orbiting mirrors for beamed propulsion and space solar power.

Robert Clark wrote:

What would be the size of the collector array at Earth to capture most of
the light focused from the 1 km wide mirror located at the Sun, i.e., the
size of the Airy disk at the Earth? How large at Proxima Centauri?


The sun is not a point source, which means you can't focus it at any
significant distance.

--
Mvh./Regards, Niels Jørgen Kruse, Vanløse, Denmark
  #6  
Old June 3rd 17, 02:57 PM posted to rec.arts.sf.science,sci.space.policy,sci.optics,sci.physics,sci.military.naval
Robert Clark[_5_]
external usenet poster
 
Posts: 245
Default Close Sun-orbiting mirrors for beamed propulsion and space solar power.

"0something0" wrote in message
...
================================================== ==================
Its also going to need to have YUUGE radiators and be able to operate at
high temperatures. The radiator needs to stay inside the shadow of the solar
array, which will limit how big it can be.

Assuming that in that distance, you get 55800 watts/square meter(from a
figure on Wikipedia and Space.com), and we use the equation

A = P / (ε * σ * T^4)

From He http://www.projectrho.com/public_htm...asicdesign.php

Few assumptions: We use the alloy with the highest known melting point with
a max emissivity. That is 4488 degrees kelvin. We also assume a 1km^2 square
array. So, it collects 44,800,000,000 watts, or 44 gigawatts of heat. So,
the equation substituted is

A = 44,800,000,000 watts/(1*5.670367(13)*10^−8*W* 1 m^−2*1 K^−4*4488 k) =

https://www.wolframalpha.com/input/?...224488.15+K%22

Umm... did I do it right? If I did, Its not that bad!
================================================== ==================

What's the area you conclude is required for the radiators?

In any case, what you want is most of the power to be reflected away by the
mirrors.

BTW, I estimate the power per square meter is 862,000 watts/square meter
based on the fact the light power goes inversely by the square of the
distance and 3.7 million miles is 25 times closer than the Earth's distance
of 93 million miles.

Bob Clark

----------------------------------------------------------------------------------------------------------------------------------
Finally, nanotechnology can now fulfill its potential to revolutionize
21st-century technology, from the space elevator, to private, orbital
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:

Nanotech: from air to space.
https://www.indiegogo.com/projects/n...ce/x/13319568/
----------------------------------------------------------------------------------------------------------------------------------

  #7  
Old June 17th 17, 02:22 PM posted to rec.arts.sf.science,sci.space.policy,sci.optics,sci.physics,sci.military.naval
Robert Clark[_5_]
external usenet poster
 
Posts: 245
Default Close Sun-orbiting mirrors for beamed propulsion and space solar power.

"Robert Clark" wrote in message news ================================================== =====================
NASA just announced a solar probe to travel quite close to the Sun, about
3.7 million miles from the solar surface:

Nasa’s hotly anticipated solar mission renamed to honour astrophysicist
Eugene Parker.
Renamed the Parker Solar Probe to honour solar astrophysicist who predicted
high speed solar wind, the spacecraft will attempt to get close to sun’s
surface.
Wednesday 31 May 2017 07.08 EDT
https://www.theguardian.com/science/...lar-probe-plus

Spacecraft able to get this close to the Sun could potentially allow beamed
interstellar propulsion. For a spacecraft of any size, you would need huge
amounts of beamed power. Where to get it? If you make the beam be
solar-powered then can just use space-borne mirrors to focus the Suns rays.
But the mirror(s) would have to be impractically large if they were in Earth
orbit.

But what if we placed them close to the Sun? At the distance quoted of 3.7
million miles away from the Sun a mirror 1 km on a side could collect a
terawatt worth of power.

Note this could also be used for space solar power when beamed towards
Earth.

Bob Clark

---
================================================== =====================

At the distance of the Parker probe, a 1 km sq. mirror could collect a
terawatt of power for beamed propulsion or space solar power beamed to
Earth.

But could we put the mirror actually on the surface of the Sun? The Sun puts
out 3.86X10^26 watts of power,
http://m.wolframalpha.com/input/?i=s...nosity&x=0&y=0.

Given its 700,000 km radius, this amounts to over 60 terawatts per sq. km.
This is 3 times the total energy usage of humans on Earth from all sources.

Could we have a station on the Sun’s surface that would persist long term?
The Sun’s surface is at about 5,500 C. The highest temperature ceramic we
have is at about 4,000 C:

Rediscovered ceramic Hafnium Carbide can withstand temperatures three times
hotter than lava at 4050 celsius and could help enable hypersonic planes.
brian wang | September 17, 2014
https://www.nextbigfuture.com/2014/0...m-carbine.html

However, there are cases such as with rocket engine combustion chambers
where the operating temperature is well above the melting point of the
material composing the engine. The reason this is possible is that in order
for a material to undergo a phase change from solid to liquid not only does
it have to be at the melting point but a sufficient quantity of heat known
as the heat of fusion has to be supplied to it.

So with high performance rocket engines such as the SSME’s a cooling
techniques known as regenerative cooling is used that circulates cool fuel
around the engine to draw off adequate heat to prevent melting from
occurring.

However, with rocket engines this cooling fuel is burned or dispensed with
after being used for the cooling. So this wouldn’t work for a power station
existing long term on the surface of the Sun. You would need something like
a refrigeration system.

The Parker probe will use a refrigeration system to lower the temperature of
the components of the spacecraft from 1,400 C to room temperature. This is
about the same temperature drop as the temperature drop from the Sun’s
surface to the maximum temperature of our high temperature ceramics. So it
should be possible to do this temperature drop on the surface of the Sun
using our highest temperature ceramics.

Still, we might not want the extra difficulty of landing on the Sun. If we
make the distance to the Sun of our beaming station about 1/3rd that of the
Parker probe we would be at 10 terawatts per sq. km. Two of these would
provide the entire energy requirements for the entire human population, and
the surrounding temperatures wouldn’t be so extreme.

Bob Clark


----------------------------------------------------------------------------------------------------------------------------------
Finally, nanotechnology can now fulfill its potential to revolutionize
21st-century technology, from the space elevator, to private, orbital
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:

Nanotech: from air to space.
https://www.indiegogo.com/projects/n...ce/x/13319568/
----------------------------------------------------------------------------------------------------------------------------------

  #8  
Old June 17th 17, 03:48 PM posted to sci.space.policy,sci.optics,sci.physics
Sегgi о
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Posts: 4
Default Close Sun-orbiting mirrors for beamed propulsion and space solarpower.


The Parker probe will use a refrigeration system to lower the
temperature of the components of the spacecraft from 1,400 C to room
temperature. This is about the same temperature drop as the temperature
drop from the Sun’s surface to the maximum temperature of our high
temperature ceramics. So it should be possible to do this temperature
drop on the surface of the Sun using our highest temperature ceramics.


the major constraint is; the limited amount of heat can the probe get
rid of by radiate it out into cold space on the back side. This is only
a few hundred watts. (do the calculation)
[hint http://hyperphysics.phy-astr.gsu.edu...mo/stefan.html ]

this means the solar shield *must be* a wideband optical and heat reflector

  #9  
Old June 17th 17, 04:16 PM posted to sci.space.policy,sci.optics,sci.physics
Phil Hobbs[_3_]
external usenet poster
 
Posts: 13
Default Close Sun-orbiting mirrors for beamed propulsion and space solarpower.

On 06/17/2017 10:48 AM, Sегgi о wrote:

The Parker probe will use a refrigeration system to lower the
temperature of the components of the spacecraft from 1,400 C to room
temperature. This is about the same temperature drop as the
temperature drop from the Sun’s surface to the maximum temperature of
our high temperature ceramics. So it should be possible to do this
temperature drop on the surface of the Sun using our highest
temperature ceramics.


the major constraint is; the limited amount of heat can the probe get
rid of by radiate it out into cold space on the back side. This is only
a few hundred watts. (do the calculation)
[hint http://hyperphysics.phy-astr.gsu.edu...mo/stefan.html ]

this means the solar shield *must be* a wideband optical and heat reflector


And of course that the Sun does not have a solid surface.

Of course you could visit it at night.


Cheers

Phil Hobbs
  #10  
Old June 17th 17, 07:37 PM posted to sci.space.policy,sci.optics,sci.physics
Sегgi о
external usenet poster
 
Posts: 4
Default Close Sun-orbiting mirrors for beamed propulsion and space solarpower.

On 6/17/2017 10:16 AM, Phil Hobbs wrote:
On 06/17/2017 10:48 AM, Sегgi о wrote:

The Parker probe will use a refrigeration system to lower the
temperature of the components of the spacecraft from 1,400 C to room
temperature. This is about the same temperature drop as the
temperature drop from the Sun’s surface to the maximum temperature of
our high temperature ceramics. So it should be possible to do this
temperature drop on the surface of the Sun using our highest
temperature ceramics.


the major constraint is; the limited amount of heat can the probe get
rid of by radiate it out into cold space on the back side. This is only
a few hundred watts. (do the calculation)
[hint http://hyperphysics.phy-astr.gsu.edu...mo/stefan.html ]

this means the solar shield *must be* a wideband optical and heat reflector


And of course that the Sun does not have a solid surface.

Of course you could visit it at night.


Cheers

Phil Hobbs


another problem, intense gamma radiation from the sun, that will screw
up computers,

Earth atmosphere stops much of it here, the equivelent of 12 feet of
Aluimium, at Earths distance, 90,000,000 miles.

Parker is going to 3,700,000 and would need 50 feet of Alu or more for a
shield ? [1/r^2]
 




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