On Mon, 2 Jan 2006 18:43:50 -0000, "tg"
wrote:

I say the following as an Englishman, born and living in the UK.
The americans have again proven themselves the masters of technology and craftmanship. Tonight on the news was a story about NASA's
Spirit and Opportunity mission on Mars. Those little robots are still going two years after landing - well beyond their expected
sell-by date. Well done America, I applaud your technical exellence.

http://news.yahoo.com/s/afp/20051230...NlYwMlJVRPUCUl

WASHINGTON (AFP) - Nearly two years after landing on the Red Planet,
NASA exploration rovers Spirit and Opportunity continue to send back amazing images and information about Mars in a mission long
outpacing expectations.

Since landing on opposite sides of Mars in January 2004, the US space agency's two robotic explorers have plowed over five
kilometers (three miles) of the planet's surface and sent back more than 130,000 pictures, many of them stunning depictions of a
desolate, arid but highly varied landscape.

The two also continue to reveal Mars' geological secrets, digging into soil and overturning rocks to provide evidence that water
once featured on the planet's surface, creating possibly habitable conditions.

But what has equally pleased the National Aeronautics and Space Administration is that the two rovers have far exceeded their
90-day missions, lasting through one full Mars year -- 669 Mars days, the equivalent of 687 Earth days.




"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

On Mon, 02 Jan 2006 20:41:03 GMT, Gunner
wrote:

On Mon, 2 Jan 2006 18:43:50 -0000, "tg"
wrote:

I say the following as an Englishman, born and living in the UK.
The americans have again proven themselves the masters of technology and craftmanship. Tonight on the news was a story about NASA's
Spirit and Opportunity mission on Mars. Those little robots are still going two years after landing - well beyond their expected
sell-by date. Well done America, I applaud your technical exellence.

http://news.yahoo.com/s/afp/20051230...NlYwMlJVRPUCUl

WASHINGTON (AFP) - Nearly two years after landing on the Red Planet,
NASA exploration rovers Spirit and Opportunity continue to send back amazing images and information about Mars in a mission long
outpacing expectations.

Since landing on opposite sides of Mars in January 2004, the US space agency's two robotic explorers have plowed over five
kilometers (three miles) of the planet's surface and sent back more than 130,000 pictures, many of them stunning depictions of a
desolate, arid but highly varied landscape.

The two also continue to reveal Mars' geological secrets, digging into soil and overturning rocks to provide evidence that water
once featured on the planet's surface, creating possibly habitable conditions.

But what has equally pleased the National Aeronautics and Space Administration is that the two rovers have far exceeded their
90-day missions, lasting through one full Mars year -- 669 Mars days, the equivalent of 687 Earth days.




"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

I agree. Still think they should have stirling engine roving bots on
the moon. I'm not a rocket scientist, but seems the temperature
difference from shaded and sun side would enable them to having lots
of power. Maybe someone can explain how heat is dissipated in a
vacuum. What is a day on the moon? Half of 28? Maybe that's the big
drawback, being in the shade and freezing for so long and then back to
toast.

I go to the rover site once in awhile to check on them. Wish there was
more interest in them so that they would be more forthcoming of
detailed dissertations of their progress.

"Sunworshipper" wrote in message
...

I agree. Still think they should have stirling engine roving bots on
the moon. I'm not a rocket scientist, but seems the temperature
difference from shaded and sun side would enable them to having lots
of power.

You need to have the hot and cold at the same time with a stirling. One side
is kept hot, the other side is kept cold.

Maybe someone can explain how heat is dissipated in a
vacuum.

Radiation or conduction to something solid. No convection, and there are no
fluids to conduct to, either.

--
Ed Huntress

Ed Huntress wrote:
"Sunworshipper" wrote in message
...

I agree. Still think they should have stirling engine roving bots on
the moon. I'm not a rocket scientist, but seems the temperature
difference from shaded and sun side would enable them to having lots
of power.


You need to have the hot and cold at the same time with a stirling. One side
is kept hot, the other side is kept cold.

Nothing to it. The side of the body facing out is heated by direct
radiation from the sun. The dark side of that same body would receive
no radiation except that that is reflected from the moon's surface under
the body.
Hot on top, cold on the belly.

Rex B wrote:



Nothing to it. The side of the body facing out is heated by direct
radiation from the sun. The dark side of that same body would receive
no radiation except that that is reflected from the moon's surface under
the body.
Hot on top, cold on the belly.

Rex, have you run the numbers on radiated cooling for an engine?

I haven't either, but my million dollar seat of the pants intuition that
tells me that the area of black bodied radiator needed would be bigger
than the belly.

--
Accidental creation should not be taught as a fact.
Intelligent creation should not be banned from teachings as
unconstitutional.

Sunworshipper wrote: Maybe someone can explain how heat is dissipated in a
vacuum.

Radiation, and some conduction to the surface.
...lew...

Clark Magnuson wrote:

Rex B wrote:
Nothing to it. The side of the body facing out is heated by direct
radiation from the sun. The dark side of that same body would receive
no radiation except that that is reflected from the moon's surface
under the body.
Hot on top, cold on the belly.


Rex, have you run the numbers on radiated cooling for an engine?

I haven't either, but my million dollar seat of the pants intuition that
tells me that the area of black bodied radiator needed would be bigger
than the belly.


If the radiator was aimed at the sky and shielded from the incoming
radiation from the sun it would make a pretty good cold sink.
...lew...

Wasnt the ESA deeply involved in the rover mission?

Gunner wrote:
On Mon, 2 Jan 2006 18:43:50 -0000, "tg"
wrote:


I say the following as an Englishman, born and living in the UK.
The americans have again proven themselves the masters of technology and craftmanship. Tonight on the news was a story about NASA's
Spirit and Opportunity mission on Mars. Those little robots are still going two years after landing - well beyond their expected
sell-by date. Well done America, I applaud your technical exellence.

http://news.yahoo.com/s/afp/20051230...NlYwMlJVRPUCUl

WASHINGTON (AFP) - Nearly two years after landing on the Red Planet,
NASA exploration rovers Spirit and Opportunity continue to send back amazing images and information about Mars in a mission long
outpacing expectations.

Since landing on opposite sides of Mars in January 2004, the US space agency's two robotic explorers have plowed over five
kilometers (three miles) of the planet's surface and sent back more than 130,000 pictures, many of them stunning depictions of a
desolate, arid but highly varied landscape.

The two also continue to reveal Mars' geological secrets, digging into soil and overturning rocks to provide evidence that water
once featured on the planet's surface, creating possibly habitable conditions.

But what has equally pleased the National Aeronautics and Space Administration is that the two rovers have far exceeded their
90-day missions, lasting through one full Mars year -- 669 Mars days, the equivalent of 687 Earth days.





"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

On Mon, 02 Jan 2006 16:27:04 -0600, Rex B
wrote:


Ed Huntress wrote:
"Sunworshipper" wrote in message
...

I agree. Still think they should have stirling engine roving bots on
the moon. I'm not a rocket scientist, but seems the temperature
difference from shaded and sun side would enable them to having lots
of power.


You need to have the hot and cold at the same time with a stirling. One side
is kept hot, the other side is kept cold.

Nothing to it. The side of the body facing out is heated by direct
radiation from the sun. The dark side of that same body would receive
no radiation except that that is reflected from the moon's surface under
the body.
Hot on top, cold on the belly.

Check out
http://ares.jsc.nasa.gov/HumanExplor.../Part1/SWS.htm

to see a scientific instrument that is setting on the moon. It is
insulated on five sides with 40 layers of alternating silk and silver
mylar. The sixth side has a radiator assembly that rejects heat
reflected from the lunar surface while allowing the radiation of heat
to the lunar sky.. The belly had to be insulated because of solar
energy reflected to the bottom side.

According to Rex B "":

Ed Huntress wrote:
"Sunworshipper" wrote in message
...

I agree. Still think they should have stirling engine roving bots on
the moon. I'm not a rocket scientist, but seems the temperature
difference from shaded and sun side would enable them to having lots
of power.


You need to have the hot and cold at the same time with a stirling. One side
is kept hot, the other side is kept cold.

Nothing to it. The side of the body facing out is heated by direct
radiation from the sun. The dark side of that same body would receive
no radiation except that that is reflected from the moon's surface under
the body.
Hot on top, cold on the belly.

But -- does a stirling engine self-start? I though that they
had to be given a spin by hand once the temperature differential was
established.

I guess that a battery could be dedicated to that task after the
lunar night was over. If the battery could survive the cold of the
14-day lunar night.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
ervers.com...
According to Rex B "":

Ed Huntress wrote:
"Sunworshipper" wrote in message
...

I agree. Still think they should have stirling engine roving bots on
the moon. I'm not a rocket scientist, but seems the temperature
difference from shaded and sun side would enable them to having lots
of power.


You need to have the hot and cold at the same time with a stirling.
One side
is kept hot, the other side is kept cold.

Nothing to it. The side of the body facing out is heated by direct
radiation from the sun. The dark side of that same body would receive
no radiation except that that is reflected from the moon's surface under
the body.
Hot on top, cold on the belly.

But -- does a stirling engine self-start? I though that they
had to be given a spin by hand once the temperature differential was
established.

Like a single-acting steam engine, a normal single-acting stirling requires
3 power cylinders to be self-starting. Saab once built one that had
something like 8 or 10 cylinders, driving through a swashplate.

The free-piston stirlings, which are linear alternators, are started by
powering the alternator to act as a temporary starting motor.

--
Ed Huntress