On 6/21/2017 8:10 AM, Robert Clark wrote:
"Sегgi о" wrote in message news
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On 6/20/2017 12:31 PM, Robert Clark wrote:
"Robert Clark" wrote in message news
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.
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.
refrigeration wont work. if reflectivity is 99.9% you still ave to move
how many terrawatts(?) from front to back of the spacecraft, AND radiate
that out to cold space on the backside ??
also Gamma rays are going to cook it, +fry electonics.
what are the gamma ray radiation levels close to the sun ?
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Look at it in terms of how much needs to be radiated per unit area. This
research project expects to reflect 99.9% of the light energy away:
April 6, 2017
Solar Surfing
Robert Youngquist
NASA Kennedy Space Center
Quote:
Description
We propose to develop a novel high temperature coating that will reflect up
to 99.9 % of the Sun’s total irradiance, roughly a factor of 80 times
better
than the current state-of-the-art. This will be accomplished by leveraging
off of our low temperature coating, currently being developed under NIAC
funding. We will modify our existing models to determine an optimal high
temperature solar reflector, predict its performance, and construct a
prototype version of this coating. This prototype will be sent to our
partner at the Johns Hopkins Applied Physics Laboratory where it will be
tested in an 11 times solar simulator. The results of this modeling/testing
will be used to design a mission to the Sun, where we hope to come to
|
Quote:
within
one solar radius of the Sun’s surface, 8 times closer than the closest
distance planned for the upcoming Solar Probe Plus. This project will
substantially advance the current capabilities of solar thermal protection
systems, not only potentially allowing “Solar Surfing”, but allowing better
thermal control of a future mission to Mercury.
|
https://www.nasa.gov/directorates/sp.../Solar_Surfing
At that distance, the solar radiance is 60 megawatts per square meter.
So 1/1,000 of this would have to be radiated away, this is 60,000 watts.
That is not a lot over a square meter.
I think you can figure out the temperature rise from that, 60,000 watts
out of a sq meter (too busy right now) to cold space, could be glowing red.
but that mirror is not real yet, 80 times is huge. and I think Gamma
rays will be a larger factor.