[amsat-bb] Re: More Future Thoughts

2009-07-05 Thread Gordon JC Pearce
On Sat, 2009-07-04 at 09:13 -0400, Jeff Davis wrote:

> I recall reading something from G0RMF about adapting a CubeSat to include 
> some sort of a propulsion system to get to a mid-Earth orbit:
> 
> http://g0mrf.com/MEOSAT.htm
> 
> I have no idea if this is viable, but it seems to me that if we want to 
> place assets higher than LEO these are the kinds of ideas we should be 
> kicking around on the BB and perhaps leave the moon base installation ideas 
> for AMSAT members in 2050 to figure out how to make work and to fund.

I do see one snag with that article.  The author talks about reducing
transponder bandwidth to increase the transmit power, which is fair
enough - that 13dB has to come from somewhere.  However, because the
footprint is correspondingly larger there will be much more contention
for bandwidth because more people will be attempting to use it.

Of course, the increased complexity of the ground station will put some
people off, so perhaps not as many people will be capable of hitting the
MEO satellite.  Furthermore, if it was used for narrow band modes like
CW and PSK, 50kHz might well be perfectly adequate.

I could be completely wrong, though.

Gordon 2M0YEQ

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[amsat-bb] Re: More Future Thoughts

2009-07-04 Thread Tony Langdon
At 02:52 AM 7/5/2009, you wrote:

>AMSAT as a whole (I mean the membership) needs a new challenge and dream
>that will bring out the very best in it to build what ever comes up. The
>Moon could be that new challenge as we have NEVER designed anything that
>would actually LAND and operate in that hostile environment. Is it
>viable, who knows! We can only ask ourselves that question and then step
>up to the challenge.

Well, the challenge as I see it is not so much in the RF side of 
things, but being to take advantage of the available (relatively 
affordable) launch opportunities available (i.e. LEO), then coming up 
with a way to being able to move the bird into an orbit more 
suitable.  Yes, propulsion hasn't been AMSAT's strong point, but for 
most of the last 20 years, I only recall LEOs being put up (AO-40 
being the only exception I can recall in that timeframe).

So the challenge is to find a means of propulsion that is relatively 
safe, inexpensive and lightweight, but can move a satellite into a 
significantly higher orbit (e.g. MEO).  I'd imagine that such a form 
of propulsion is probably only found in science fiction, but how 
close can one get in the real world?  Are there any universities 
working on cheaper ways to move satellites around, once launched, 
that need a suitable test mass (that happens to have a transponder or 
two on board)?

73 de VK3JED / VK3IRL
http://vkradio.com

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[amsat-bb] Re: More Future Thoughts

2009-07-04 Thread Tony Langdon
At 11:13 PM 7/4/2009, Jeff Davis wrote:

>What about other orbits that may not be as desirable as HEO but that offer
>better coverage than low-earth?
>
>I recall reading something from G0RMF about adapting a CubeSat to include
>some sort of a propulsion system to get to a mid-Earth orbit:

This idea does have merit.  As you've implied, we'd probably never 
get a ride directly to such an orbit, so some means of (relatively) 
foolproof and (relatively) inexpensive means of propulsion would need 
to be utilised.

Someone would also need to do the delta-V calculations, to see what 
sort of orbit would be feasible for such a small satellite to 
achieve.   There's also the possible issue of the satellite spending 
most of its life in the Van Allen belts, unless we can get the 
altitude "just right".

73 de VK3JED / VK3IRL
http://vkradio.com

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[amsat-bb] Re: More Future Thoughts

2009-07-04 Thread James French
On Sat, 2009-07-04 at 09:13 -0400, Jeff Davis wrote:
> It's interesting to watch how the desperation to have assets in high orbit 
> has driven the ideas ever more grandiose here on the old -BB. We've moved 
> from putting a "simple" transponder (as if there were such a thing) 35,000 
> miles over our head to landing a repeater a quarter million miles away on 
> the Moon and using robotic rovers to lay directional antennas along the 
> lunar surface...

Yes, people have grandiose designs and wishes for life.

> 
> What's next, a Jovian constellation of amateur satellites?
> 
> This is almost directly the result of having added the "government" into the 
> fictional scenario. Whenever a new idea starts with, "maybe we can get the 
> government to give us a ride..." then what follows can be as ostentatious as 
> we like because of the perception that the government can afford to do 
> really BIG things.

I brought 'government' up as an entity that we night help shave a few
dollars off a proposed project that MIGHT come up to supply the
transponder equipment for. I never mentioned anything about a financial
gain for AMSAT.

> 
> And we invariably try to justify that they should want to do this because of 
> "emergency communication".

This was NEVER brought up during the discussion about placing a
transponder on the Moon. NEVER!!

> 
> It would seem to be more constructive to substitute the words "big magical 
> genie" in your plans everywhere you use the word "government" or "NASA". 
> That way when you write, "if we could just get a big magical genie to give 
> us a ride to the Moon..." the reality will sink in and it probably won't 
> seem like such a grand idea before it sees the light of day.

As I mentioned a moment ago, I never said anything about financial gains
from ANY government. I mentioned 'IF' we could get a ride, MAYBE we
could help justify it with providing equipment.

> 
> We need to disabuse ourselves of the ridiculous notion that the government 
> is anxious and willing to stuff our pockets with cash just because "when all 
> else fails". Need we be reminded that we're in the midst of the worst global 
> economic recession since the great depression? Tax revenues are low while 
> debt is unbelievably high. Politicians may be stupid but they're going to 
> easily sniff out the nonsense of spending millions of dollars so a few 
> hundred radio hams can enjoy their high-tech hobby.
> 
> (And who really wants  them to do that anyway? What would be your reaction 
> if you read the news tomorrow that the government was going to spend $20 
> million tax dollars to help promote Frisbee golf, coin collecting, or some 
> other hobby?)

In the current scheme of things, it wouldn't surprise me that ANY
government is supporting ANY hobby with admendments and pork-belly
add-ons to things right now. Do you read everything that ANY government
proposes to make sure they are spending the taxpayers money CORRECTLY?

> 
> When life gives you lemons you make lemonade. We can't get to HEO, so what 
> can we do?
> 
> I think our best option is to create a lot more interesting things to do at 
> LEO since we know we can get there; but let's make sure we aren't leaving a 
> stone un-turned.
> 
> What about other orbits that may not be as desirable as HEO but that offer 
> better coverage than low-earth?
> 
> I recall reading something from G0RMF about adapting a CubeSat to include 
> some sort of a propulsion system to get to a mid-Earth orbit:
> 
> http://g0mrf.com/MEOSAT.htm
> 
> I have no idea if this is viable, but it seems to me that if we want to 
> place assets higher than LEO these are the kinds of ideas we should be 
> kicking around on the BB and perhaps leave the moon base installation ideas 
> for AMSAT members in 2050 to figure out how to make work and to fund.

And I have no idea if any of these things that everyone is talking about
is viable given the current state of economy. Things have changed and
not for the better for ANYONE. NOTHING is for free and if offered for
'free', I would take a good look to see why it was free and what it was
going to cost me in the long run.

The only thing we as AMSAT can do right now is think of ideas and make
suggestions right now. AMSAT has plans for making 'off-the-shelf'
transponders that would be ready for a ride if the option comes up. But
the kicker is, what should that transponder be? L/s? U/v? S/u? V/v?
Personally, I am tired of V/u transponders. There is NO challenge in
that mode anymore. Been there, done that! I want the challenge of the
higher frequencies - 1.2GHz, 2.4GHz, 3.4GHZ, 5.7GHz, and 10GHz, even
24GHz. AO-40 should that 24GHz was feasible. 

AMSAT as a whole (I mean the membership) needs a new challenge and dream
that will bring out the very best in it to build what ever comes up. The
Moon could be that new challenge as we have NEVER designed anything that
would actually LAND and operate in that hostile environment. Is it
viable, who knows! We ca