Breaking News! NASA Astronaut Marsha Ivins ****ting Her Diapers!

Derek Lyons wrote:

It's not that the sources are unreliable - it's that adding a large
number of EV's to the equations changes the load curves considerably
from the current norm.

You miss the point -- PHEVs offer unparalleled flexibility in
when that demand occurs. Dispatchable demand is very much
liked by utility operators, precisely because it lets *them*
have more control over the shape of the demand curve.

Paul

Alex Terrell wrote:

No capital cost - but considerable potential life cycle cost.

Though the batteries being designed are good for 10,000 cycles, which
equals 1 million kilometres in a typical PHEV, which is more than
adequate.

The issue isn't batteries - it's the liquid fuel.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

On Wed, 6 Jun 2007 22:05:08 -0400, "Jonathan" wrote:

"Henry Spencer" wrote in message
...

You can't realistically hope to build and
operate powersats with the sort of space transportation we've got now --
it's a whole new order of magnitude -- so the current situation, in which
access to space is difficult and infrequent, simply isn't relevant.

You guys just don't get it. We need a /reason/ to make space
transportation cheap. SSP is the /reason/ to fund low cost
to orbit.

SSP is an *inadequate* reason to fund low cost to orbit. People who
have money, and this includes the United States Congress, will not
invest in low cost to orbit in order to pursue SSP. They are not
going to do that, period, full stop.

Find a better reason, or give up and go away.


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

On Wed, 6 Jun 2007 12:28:58 -0500, "Mike Combs"
wrote:

"Rand Simberg" wrote in message
...
On Tue, 05 Jun 2007 14:32:08 -0700, in a place far, far away, Hyper
made the phosphor on my monitor glow in such a
way as to indicate that:

Powersats in LEO to me doesn't seem to be much better than just building
the thing on the ground. At night, a powersat visible from the ground
will probably also be in the Earth's shadow.

In shadow only twice a year during equinoxes, and only for an hour or
so per day.

That's the case only for GEO. We were talking about LEO.

I guess the only advantage of a LEO SPS over ground-based solar is no
interruptions due to cloud cover. At least you'd have a solid 50%
availability of solar power.

You could put it in a dawn/dusk sun-synchronous orbit with constant
illumination. And you can keep your arrays always perpendicular to
the solar flux; those two plus getting above the atmosphere would
give you a fourfold improvement over even the best terrestrial sites.

But you have the huge disadvantage that most of your orbit will be
out of LOS of your rectenna. And that probably gets worse if you
go sun-synchronous.


Even if a SPS was built in LEO just as an experimental proof-of-concept
prototype, I'd still like to see it raised to GEO eventually.

Won't work. If it's built for LEO operations, the transmitting antenna
will be an order of magnitude too small for GEO operations. And no, we
aren't going to put a GEO-sized antenna on a proof-of-concept prototype.
The GEO-sized antenna is what effectively sets the minimum scale of the
whole thing, which is to say "gargantuan".


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

In article ,
Jonathan wrote:
No argument there. Of course if it were demonstrated, even on a small
scale, people would stop laughing. But as long as they're laughing,
it's hard to demonstrate.

If Bush had not killed SSP, we would ALREADY have a demonstrator flying...

*If* it had been generously funded (over a billion dollars in five years
is not trivial), and *if* it had stayed on schedule, and *if* supporting
systems had likewise been funded and stayed on track, and *if* the LEO
beaming demonstration had been selected for the 2006-7 demonstrator (note
that there were several other options), something that had some sort of
vague resemblance to a powersat might have flown sometime around now.

It probably *wouldn't* have been a sufficiently impressive demo to
convince skeptics, though. For that, one of the later demonstrators would
have been needed -- again, assuming that NASA actually picked the beaming
demonstrations as the flight tests of choice. The mere fact that they
were considering alternatives strongly suggests that they were thinking in
narrow engineering terms, of solving the engineering problems rather than
closing powersats' credibility gap.

There's a big difference between a "technology flight demonstration" and a
demonstrator powersat -- between something that helps resolve some of the
obscure technical problems, and something that persuades people who
thought the idea was obviously a crazy fantasy.

This was not another study, it was Congress telling NASA
to start building an ambitious large scale SSP program.

Uh, no -- it was Congress telling NASA to study the idea a bit. Note that
(as the cited report mentions) even the work to that date was badly
hampered by inadequate funding levels, i.e. weak Congressional support.
When Congress really cares about something, Congress provides money.

Chairman Rohrabacher opened the hearing by stating that
space solar power (SSP) is "precisely what NASA as an
agency should be all about"...

So why the inadequate funding? Answer: because Rohrabacher's opinions
about this are not widely shared in Congress. Rohrabacher was *far* more
interested in space than a typical Congressman... and the less said about
the Senate the better.

Nonsense, a democratic Congress will eventually return NASA to
the idea of SSP.

You've completely failed to justify this remarkable claim.

I'm hoping by the next general election the idea
takes hold enough to become a campaign issue.

There is not the slightest chance of that. Nobody thinks it's credible
enough to even bring it up.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

In article ,
Jonathan wrote:
But maybe you're correct, spending the next twenty years
to build a shelter for four people on the moon is a better
use of NASA funds, time and expertise.

Note that John didn't say that. What he said was that you haven't a
prayer of convincing skeptical people that powersats are better. If
you don't understand the difference between reality and perception,
nothing you say about politics can be taken seriously.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

In article ,
Jonathan wrote:
You guys just don't get it. We need a /reason/ to make space
transportation cheap.

One hallmark of the fanatic is that when you tell him his solution won't
work, he claims you don't understand the problem.

Have any of you ever watched a greyhound race?
Think of SSP as that little rabbit that makes the race go.

Now imagine that what's moving in front of them is a little sign saying
"there's a rabbit here". Since this doesn't look or smell like a rabbit
to any of the dogs, nothing happens. Jumping up and down and yelling,
"there's a rabbit there, you're supposed to race after it!!" will not get
them moving. Not even if you think it's really, really important. Not
even if a real rabbit would be a really good reason for them to run.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

In article ,
Jonathan wrote:
Lost your religion? This pessimism must be based on the past
performance of our political system. We live in an entirely different
political world these days.

"The four most expensive words ever spoken are 'this time is different'."

Wisdom is a collective property, and
the internet is quickly allowing the weight of the people to assert itself
over our political system.

"The sum of gossip does not produce either knowledge or insight." --
Ursula Franklin.

...I'm looking for the 'magic goal' that
will /sell itself/ even if only a few lamers are pushing it.

Right -- now consider the possibility that no such goal exists. Hint:
if it would sell itself, why hasn't it done so already?

Well, I intend to spend a couple more years pumping this. Any advice
that can make the message more effective would be appreciated.

You're already boring and annoying people here with your stubborn
repetition of poorly-justified fantasies and your total ignorance of
politics. Stop posting to Usenet and start talking to Congressmen --
actually *talking to Congressmen* and trying to get your message across,
not just telling people how easy it will be to convince Congressmen.
Convert half a dozen of them to enthusiastic and vocal supporters, and
your claims will have much more credibility. Fail to do so, and you will
be wiser.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

On 9 Jun, 01:19, John Schilling wrote:
On Wed, 6 Jun 2007 12:28:58 -0500, "Mike Combs"

wrote:
"Rand Simberg" wrote in message
...
On Tue, 05 Jun 2007 14:32:08 -0700, in a place far, far away, Hyper
made the phosphor on my monitor glow in such a
way as to indicate that:
Powersats in LEO to me doesn't seem to be much better than just building
the thing on the ground. At night, a powersat visible from the ground
will probably also be in the Earth's shadow.
In shadow only twice a year during equinoxes, and only for an hour or
so per day.
That's the case only for GEO. We were talking about LEO.
I guess the only advantage of a LEO SPS over ground-based solar is no
interruptions due to cloud cover. At least you'd have a solid 50%
availability of solar power.

You could put it in a dawn/dusk sun-synchronous orbit with constant
illumination. And you can keep your arrays always perpendicular to
the solar flux; those two plus getting above the atmosphere would
give you a fourfold improvement over even the best terrestrial sites.

But you have the huge disadvantage that most of your orbit will be
out of LOS of your rectenna. And that probably gets worse if you
go sun-synchronous.

Even if a SPS was built in LEO just as an experimental proof-of-concept
prototype, I'd still like to see it raised to GEO eventually.

Won't work. If it's built for LEO operations, the transmitting antenna
will be an order of magnitude too small for GEO operations. And no, we
aren't going to put a GEO-sized antenna on a proof-of-concept prototype.
The GEO-sized antenna is what effectively sets the minimum scale of the
whole thing, which is to say "gargantuan".

You could build a proof of concept and then move it to Earth - moon L1
to support lunar operations, which might at some point need multi MW
of power. The scaling issue would be solved by replacing the rectenna
with lasers.

goanna wrote:
In (Henry Spencer) writes:

robert casey wrote:
[...]
It's probably a lot cheaper to just build the solar power plant on the
ground (like in a desert in Arizona), even though it can only work
during the daytime. But power consumption does peak during the daytime...

Unfortunately, even Arizona gets clouded out at times, and atmospheric
absorption cuts available power early and late in the day (a particular
annoyance for the latter, since that's when the highest demand peak is).
And there is quite a bit of 24x7 base load to be supplied, and there'll
be much more of that if electricity is used to manufacture or replace
petroleum-derived liquid fuels.

True for photovoltaic, but recent developments in fairly low tech
solar thermal employ effective thermal storage to enable baseline
power without flywheels, pumped hydro or the like. For example,
http://news.com.com/8301-10784_3-9719858-7.html


The cost comparison made there is between solar thermal and gas fired
plant. Even then, they're waving their hands a bit to get the price down
to 10 cents per kWh.

They couldn't substitute for gas fired plant, because such plant is used
for peak loads, and the costs for the solar thermal plant would be based
on its use for baseload.

Coal fired stations (one of the usual ways that baseload power is
generated) have much lower costs, at around 4 cents per kWh.

Sylvia.