"Robert Clark" wrote:

"S??gi ?" wrote in message news ================================================= =======================
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 ??


He wasn't speculating, Bob. That is what the Parker Probe is going to
do.


also Gamma rays are going to cook it, +fry electonics.
what are the gamma ray radiation levels close to the sun ?


If you don't know the gamma ray levels, how can you say gamma will
cook it?

The gamma ray flux outside the surface of the Sun is essentially zero.
It all gets converted to visible photons from 170,000 years of
collisions inside the Sun on its way to the surface.


--
"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