Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_0/V15NO035.TXT

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Space Digest                Fri, 24 Jul 92       Volume 15 : Issue 035

Today's Topics:
                              ESA Future
                            Facility Tours
                    GPS for satellite positioning
    Imminent demise of comsats predicted (for the dozenth time :-)
                 Sat->Ground Optical Communications?
     Star Trek and public perception of space/science/engineering
                            Whales (SETI)

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Date: 22 Jul 92 16:25:47 GMT
From: [e-mail]
Subject: ESA Future
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Philippos A. Peleties) writes:
> In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:
>>In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>>In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:

>>>>Well, yes, but then they don't have independent acess to space, which was one
>>>>of the reasons ESA was founded in the first place.  Sort of pointless.
>>

The Arianne series would still be running with or without Hermes. There's your
independent access to space.

>>>Not at all.  Just make Russia an ESA member.  It *is* a European country!
>>
>>Well, geographically it is partly in Europe, (it's as much Asian as
>>European, if we want to get picky) but socially, economically, and

>>culturally it is pretty far off...I can't see them getting into the ESA,

>>especially with all the petty bickering and infighting among the member
>>nations.
>>
> The point is this: ex-Soviet (Russian/Ukranian) technology most likely
> will be used in some rather substantial capacity and some combination
> of the above countries will become ESA members whether they are geographically
> located in Europe or not.


Geography never mattered anyway. Canada's a member of ESA and ESA's launch
facilities are in south america. ESA's just a name, and that never stopped
politicians before...

--

================================================================================
Dave Clements, Oxford University Astrophysics Department
================================================================================
clements @ uk.ac.ox.vax            |  Umberto Eco is the *real* Comte de
dlc      @ uk.ac.ox.astro        |           Saint Germain...
================================================================================

------------------------------

Date: Friday, 24 Jul 1992 08:45:13 CET
From: [e-mail]
Subject: Facility Tours
Newsgroups: sci.space

Sorry, but I haven't followed the full story, what's about JSC and White Sands?
Regards
         -Thorsten-

------------------------------

Date: 24 Jul 92 05:33:43 GMT
From: Charles F Randall <[e-mail]>
Subject: GPS for satellite positioning
Newsgroups: sci.space

I've been told that there are _no_ satellites that use GPS for their
positioning data. I find this hard to believe. I've seen
advertisements for the Monarch GPS receivers in 'Space News'.

Does anyone know of an actual satellite that uses GPS for it's
positioning data? Or part of it's positioning data?

It is my understanding that the current level of GPS is only capable
of providing lat. and long. information and in the future, they plan
to incorporate elevation. Is this correct?

Finally, does anyone know if crew members of the Shuttle have taken up
a hand held GPS unit?

Any information would be greatly appreciated.
Thanks,
Randy

Charles F. Randall IV |    _               | "Are you kidding? I study
Aerospace Engineering |  == \---------..,  |  from crisis to crisis!"
Iowa State University |  ==___-----_____>  |       -anonymous student
[e-mail]  | _____b________d___ | <== ascii space shuttle

------------------------------

Date: 23 Jul 92 09:19:25 GMT
From: Nick Szabo <[e-mail]>
Subject: Imminent demise of comsats predicted (for the dozenth time :-)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Shari L Brooks) writes:

>As an aside.  The value (or rather, usefulness) of COMSATs is decreasing, not
>increasing; also, they are getting more expensive relative to the superior

>communications offered by fiber optics.

The second point is valid for point-to-point communications, but the
first is false.  Wall Street is bullish on space communications.
Comsat stock is near its all-time high, and large amounts of new
capital are going into mobile-communications ventures like American
Mobile Satellite Corp., Alpha Lyracom, European/Loral Globalstar,
Motorolla/Lockheed Iridium, Orbital Sciences Corp. Orbcomm, and even
more $billions are going into foreign ventures.  The mobile and broadcast

functions of comsats are not being replaced by fiber, and are expanding

far faster than the point-to-point market is moving to fiber.  The
"unused capacity" Gary keeps harping on has always been a normal part
of the comsat business; backups are necessary because of the unreliable
nature of launch services.  Both the builders and operators are making

money despite that constraint, but costs would come down even farther,
and the market expand more quickly, by making launchers more reliable.

For a successful, $multi-billion space program that pays for itself,
comsats sure get dismissed a lot. In my more derogatory moments, I start

thinking that some fans of other parts of the space program can't

stand success.  :-)


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------------------------------

Date: 
P
From: Charles F Randall <[e-mail]>
Subject: Sat->Ground Optical Communications?
Newsgroups: sci.space

Date: 24 Jul 92 05:23:51 GMT
Article-I.D.: news.1992Jul24.052351.12502
References: <[e-mail]> <[e-mail]>
Sender: USENET News System <[e-mail]>
Organization: Iowa State University, Ames, IA
Lines: 29
Source-Info:  Sender is really [e-mail]
Source-Info:  Sender is really [e-mail]


I'm looking for references concerning optical communications systems
for transmitting data from a low-Earth orbiting satellite to a ground
station.

I know that optical communications systems are typically used for
sat->sat comm. systems and can typically achieve approximately 300
Mbits/s data rates.

I also know that the atmosphere causes considerable problems when
attempting sat->ground optical communication. It is my understanding
that this limitation is the reason that the optical communication
systems are currently only applied to sat->sat.

However, I have heard that the US Navy uses (sometimes?) an optical
communication system from sat->sub. I also heard that this can be done
even with the submarine under the polar ice caps.

I'm wondering if there are currently any NASA funded research projects
concerning sat->ground optical communications.

Any information would be greatly appreciated.
Thanks,
-Randy

Charles F. Randall IV |    _               | "Are you kidding? I study
Aerospace Engineering |  == \---------..,  |  from crisis to crisis!"
Iowa State University |  ==___-----_____>  |       -anonymous student
[e-mail]  | _____b________d___ | <== ascii space shuttle

------------------------------

Date: Fri, 24 Jul 92 07:48:46 GMT
From: Colby Kraybill <[e-mail]>
Subject: Star Trek and public perception of space/science/engineering
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bob Tidrick) writes:
>
>it alone!" We have no business disturbing something which may one day evolve
>into a more complex form. However if nothing is found than it is a mear rock
>and we have dibs.


Wait a second.  Just by existing on *this* planet do we disturb the way

everything else evolves.  By your logic, we should halt our existance on

Earth.

--

Colby Kraybill
Space and Planetary Image Facility
University of New Mexico

------------------------------

Date: 24 Jul 92 06:28:48 GMT
From: Nick Janow <[e-mail]>
Subject: Whales (SETI)
Newsgroups: sci.space

[e-mail] (russell wallace) writes:

> Whales are _not_ intelligent in any significant sense of the word. If they
> were, they could prove it in about 30 seconds, by any number of means (e.g.
> whistle the prime numbers, *-* *-*-* *-*-*-*-* etc. - for that matter just
> whistle the numbers from 1 to 10). In fact, if they were intelligent, since
> they were physically quite a lot tougher than the whaling ships of the 18th
> and 19th centuries, they could have developed tactics to defeat them (e.g.
> several whales surround a whaling ship and clobber it, rather than all the
> whales trying to dive, and the ship gets one of them).

That doesn't prove that they are not intelligent.  They could have reasons for
letting men kill them; reasons that they understand but we don't.  Look at all
the absurd things humans do in the name of religion.  Aliens judging humans by
a few religious fanatics might decide that humans aren't intelligent.  :)

I'm not arguing that whales are intelligent.  However, your argument simply
isn't valid for disproving intelligence.

--

[e-mail]

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End of Space Digest Volume 15 : Issue 035
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