If only GEO we3e6 km in circumference (was Earth intercepts one part in)

> I hope that someone gets it worked out. SPS will be very important for
> Mars for several reasons. One reasons is the dust storms on Mars which could
> put ground based solar out of service for 60 to 120 Martian days a year.

Here's an article about building rectennas on Mars from local materials:

http://science.nasa.gov/science-news/science-at-nasa/1999/msad03mar99_1/

It would be surprising to me if SPS got implemented on Mars before Earth, but you never know.

Another thing I find interesting about this article is that it attributes the original idea of making propellant on Mars from local materials to O'Neill.

Regards,

Mike Combs

From: spacesettlers@yahoogroups.com [mailto:spacesettlers@yahoogroups.com] On Behalf Of jwsmith42000@...
Sent: Wednesday, February 01, 2012 9:28 PM
To: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] If only GEO were 3e6 km in circumference (was Earth inter...

I hope that someone gets it worked out. SPS will be very important for
Mars for several reasons. One reasons is the dust storms on Mars which could
put ground based solar out of service for 60 to 120 Martian days a year.

John Wayne Smith,
1000 Planets Research Co.

In a message dated 2/1/2012 9:53:33 P.M. Eastern Standard Time,
alglobus@... writes:

On Feb 1, 2012, at 8:41 AM, sraj wrote:

> Next, it says: "Nine thousand such satellites could produce the
> equivalent of all the energy produced today (roughly 15 TW)."
> ...
> Would it be possible to safely transmit so much power by microwave to
Earth?

I've calculated the heating, it is completely trivial. Much less
than 1/1000th or a degree if memory serves.

Analysis is need to see if beams would promote atmospheric chemistry.

It should be noted that an awful lot of electromagnetic energy passes
through the atmosphere today. Consider the Sun.

> What would be the area of the ground antennas?

Large, but quite a bit smaller than needed to generate the same power
with ground solar.

> Personally, to tell the truth, I feel uncomfortable with power
> satellites, unless someone can prove with 99.99%
> confidence that all this microwave will not zap the Earth.

If by zap, you mean damage a multi-thousand km rock, no. There are
specific effects that can happen and the choice of frequency makes a
big difference. Part of any major SSP project has to be an
environmental impact report. There's good reason to believe the EIR
will come out fine, but it hasn't been done. To do it properly
requires some fairly serious money, a lot more than SSP has ever
received.

It's important to remember that the alternatives, coal, gas, oil,
ground solar, wind, nuclear all have environmental impacts, some of
them pretty nasty. What SSP has to do is be better, not perfect.

> (Unfortunately blind trust in scientists and engineers is no longer
possible,
> considering the present state of our planet in the age of science and
technology. )