Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V13_0/V13_054.ZIP/V13_054

Internet Message Format | 1991-06-28 | 18KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/wbZETie00WBw8FiE4A>;
          Wed, 16 Jan 91 21:11:59 -0500 (EST)
Message-ID: <[e-mail]>
Precedence: junk
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Wed, 16 Jan 91 21:11:55 -0500 (EST)
Subject: SPACE Digest V13 #054

SPACE Digest                                      Volume 13 : Issue 54

Today's Topics:
        Re: Fwd: NASA Plans To Redesign Space Station
           Nuclear deep space power sources
              artificial aurora sighting
             Re: Humanity's Launch Window
              Galileo Update - 01/15/91
           Nuclear Rockets -- Not Dead Yet
      Re: Metrics (was Re: Rotating Joints for Habitat)
        Re: Fwd: NASA Plans To Redesign Space Station
           Re: Cameras in 0G, was: Re: MIR Vacation
               Re: solar flares
           Re: Cameras in 0G, was: Re: MIR Vacation
              Magellan Update - 01/16/91
          CRRES observations from Wash. D.C.

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

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

Date: 15 Jan 91 17:27:54 GMT
From: borg!homer![e-mail]  (Jonathan Leech)
Subject: Re: Fwd: NASA Plans To Redesign Space Station

In article <[e-mail]>, [e-mail] ("Allen W.
Sherzer") writes:
|>One of the designs proposed when Congress mandated the design be evaluated
|>eliminated most of the truss. A small part would be left to hang experiments
|>on and the rest removed. This approach also used smaller modules for building
|>the station. Each module would be self contained and could go up on a single
|>Shuttle flight. A module would be flown up, docked, and ready to go.
|>
|>IMHO this is the best option and will result in a useable station. The
|>political pressures against it however are strong.

    If adopted, this would help vindicate Oliver Harwood's modular
tetrahedral station approach. Having the temerity to propose it got him
kicked out of Rockwell in the mid-80s.
--
    Jon Leech ([e-mail])    __@/
    "Opossums ran amok in Chapel Hill this weekend..."
    _The Daily Tar Heel_, 11/1/88

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

Date: 15 Jan 91 17:36:04 GMT
From: fluke![e-mail]  (Norm Strong)
Subject: Nuclear deep space power sources

Could anyone on this newsgroups tell me what nuclear fuel is used to
power space probes, such as the Voyager?

I know they last some time, but I can't figure out what substance is used
for this purpose.

Thanks a bunch.

--

Norm Strong  ([e-mail])
2528 31st S.   Seattle WA 98144

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

Date: 15 Jan 91 04:53:08 GMT
From: sdd.hp.com!uakari.primate.wisc.edu!caen!malgudi!sunc.osc.edu![e-mail]  (Bob Marshall)
Subject: artificial aurora sighting


We observed the barium release on 15 January at 04:12UT  (11:12 EST) in
Columbus, Ohio under rather cloudy conditions.  I saw the release...greenish,
fuzzy, moon-size if the moon were up high.  I observed without binoculars
and saw it for about a minute.  It faded quickly and was lost in
the clouds, but it was possible to see it with 7x50 binoculars for several
more minutes.  Our viewing site is rather light polluted.

                Georgia Ehlers and Bob Marshall

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

Date: 15 Jan 91 06:44:07 GMT
From: agate!shelby!neon!Neon![e-mail]  (John McCarthy)
Subject: Re: Humanity's Launch Window

I don't agree with the idea that humanity has only 80 years before
it will become too poor to go into space.  I fit my definition of
an extreme optimist - someone who believes that humanity will survive
even if it doesn't take his advice.

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

Date: 15 Jan 91 19:32:20 GMT
From: snorkelwacker.mit.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 01/15/91


                         GALILEO STATUS REPORT
                            January 15, 1991

     Yesterday's SITURN, cruise science memory readout and downlink rate
change to 40 bps were all successful with the Galileo spacecraft.  Today,
there are no spacecraft activities planned.  Tomorrow, the spacecraft will
be commanded from dual-spin to all-spin operations due to the lack of valid
star sets and remain in the all-spin mode until February 25.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 14 Jan 91 23:38:50 GMT
From: rochester!sol![e-mail]  (Brian Yamauchi)
Subject: Nuclear Rockets -- Not Dead Yet


It seems I spoke too soon in my article (Who Killed Nuclear Rockets?)
of a couple months ago.

According to the January 7 issue of Aviation Week, NASA is
establishing an Office of Nuclear Propulsion which will work on both
nuclear thermal and nuclear electric propulsion for the Space
Exploration Initiative.  One of these technologies will be chosen by
the year 2000 for further development, and a "fully functional test
engine" will be built by 2005.

I'm not exactly sure what a "fully functional test engine" means -- if
this means a research prototype, it seems like it shouldn't take 15
years (given the previous research on NERVA), but if it means an
engine that could be modified for use in an actual interplanetary
spacecraft, then 2005 seems like a very reasonable date.
--
_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Computer Science Department
_______________________________________________________________________________

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

Date: 15 Jan 91 12:52:17 GMT
From: usc!wuarchive!zaphod!rpi!uupsi!sunic!lth.se![e-mail]  (Magnus Olsson)
Subject: Re: Metrics (was Re: Rotating Joints for Habitat)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Magnus Olsson) writes:
>>... even in scientific works, it is allowed to use
>>prefixes with SI units.
>
>There is one minor exception to this.  Some branches of engineering, having
>been burned too many times by unit conversions, pick a single unit of (say)
>length and use that for *everything*, no prefixes allowed.  Metric machine
>shops, for example, often do everything in millimeters, even if they're
>working on something big like an airliner wing.


Yes, and it's a very sensible practice, too - even though conversion between
metric units is simple, eliminating the need for unit conversions eliminates
one potential source of confusion.

This, however, hasn't got anything to do with which unit system you're
using.

Magnus Olsson                   | \e+      /_
Dept. of Theoretical Physics    |  \  Z   / q
University of Lund, Sweden      |   >----<
Internet: [e-mail]     |  /      \===== g
Bitnet: THEPMO@SELDC52          | /e-      \q

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

Date: Tue, 15 Jan 91 10:02:55 -0500
From: "Allen W. Sherzer" <[e-mail]>
Subject: Re: Fwd: NASA Plans To Redesign Space Station
Newsgroups: sci.space
Cc:

In article <[e-mail]>:

>Given that the US has already launched a space station and the Soviets
>have launched several (including a modular/expandable station), my
>question is: what are the hard technical problems that are making
>the Freedom design process so long (and expensive)?

The technical problmes (of which there are many) pale in comparison to
the political and managerial problems. When the project began, the main
goal in assigning work was to insure that each center had a chunk of it
and each chunk was the right size. Technical ability to carry out the
assignment was secondary. In addition, NASA ignored integration issues
for several years. To all outward appearances the thing was an aerospace/
NASA welfare program and nobody cared if anything was produced.

>2) The Truss: In particular, building it in orbit.  Someone mentioned
>that the truss was cut in the latest redesign -- did this refer to
>just the dual keel design (which was cut earlier) or the *entire*
>truss?

One of the designs proposed when Congress mandated the design be evaluated
eliminated most of the truss. A small part would be left to hang experiments
on and the rest removed. This approach also used smaller modules for building
the station. Each module would be self contained and could go up on a single
Shuttle flight. A module would be flown up, docked, and ready to go.

IMHO this is the best option and will result in a useable station. The
political pressures against it however are strong.

The interesting question is just what this press release means. My
congressional sources all say that as of last week the NASA attitude
was: 'Problem? What problem? We just need to make it smaller'. However,
if this release is correct there is hope that the basic problems will
be looked at. Most of the pressure for change will come from the Augustine
Commission. Augustine worked hand in hand with both the Space Council and
the Office of Management and Budget while preparing their recomendations.
Their findings and recomendations have already been blessed by both agencies
and many will be implimented in next years budget.

  Allen
--
+----------------------------------------------------------------------------+
|Allen W. Sherzer | America does best when it accepts a challenging mission. |
|   [e-mail]   | We invent well under pressure. Conversely, we stagnate   |
|                 | when caution prevails.   -- Buzz Aldrin                  |

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

Date: 15 Jan 91 15:28:13 GMT
From: usc!cs.utexas.edu!ut-emx![e-mail]  (Head UNIX Hacquer)
Subject: Re: Cameras in 0G, was: Re: MIR Vacation

The real problem with cameras in space is not as much 0G as vacuum, which
has a nasty habit of evaporating lubricants.  There is also the problem
of 'cold welding', which is metal getting so cold that it freezes to the
adjoining metal. These days vacuum survival might not be so important.
MIR and the Shuttle have airlocks, so not everything has to be exposed
to vacuum whenever someone takes a stroll outside :-)

The basic Hasselblad is a Single Lens Reflex camera -
with a mirror that reflects light from the lens into the viewfinder,
moves out of the way during the exposure and moves back into the light
path after.  Many SLRs rely upon gravity to **help** move the mirror back.

Also the camera had to operable by an astronaut wearing space suit gloves -
which are bulky to say the least.  You're not going to be able to focus
and shoot an Olympus OM-2 or Leica wearing those mitts.  You need BIG,
easily grapsed controls to turn and BIG buttons to push.

The Hasselblad used by NASA did NOT have the mirror - that was one less
mechanism to break.  A rangefinder was mounted on the top of the camera
body for aiming.

More expensive, yes, but going into space ain't a trip to the beach.
If you lose your vacation pictures because your camera breaks, that's
too bad.  If you lose pictures from your lunar landing because the camera
broke, you just wasted mucho $$.
--
Clyde Hoover (Shouter-To-Dead-Parrots)    |
UNIX/VMS Services            | "Any sufficently advanced technology
Compuatation Center, UT Austin         | is indisguishable from a rigged demo."
[e-mail]            |

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

Date: 15 Jan 91 22:18:27 GMT
From: uhccux!milo![e-mail]  (K.D.Leka)
Subject: Re: solar flares

In article <[e-mail]> [e-mail] ("Mike Bishop") writes:
> .....
>I am interested to find out if there are any
>predictions as to when any notable solar flares
>may be visible to amateurs?


Unfortunately, we've not got a way to absolutely predict when solar flares
are going to occur - they have no regular pattern, like an orbit of a
comet, by which to calculate when one is going to occur.

Solar Physicists have been able to study when and under what conditions
on the Sun flares are most likely to occur, and on such bases can make
predictions on the likelyhood of a flare occurring (and how major it will
be) in a particular active region, or spot group.

For amateur viewing, only the brightest flares (read: relatively rare..)
can be seen in the white-light of the photosphere, that is, the continuum
radiation one sees in a projection of the sun through a telescope or such.
Flares are more easily seen with an H-alpha filter.

So, to try and catch a flare, get a GOOD H-alpha filter, watch the Solar-
Terrestrial Alerts for reports of high flaring activity and where on the
solar disk it is occurring, then sit, watch, and wait.  Sometimes there
will be 25 flares in a 24-hr period, sometimes none.
^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^
Osborn's Law: "Variables won't; constants aren't. constraints don't."
K. D. Leka                [e-mail]
Institute For Astronomy            [e-mail]
University of Hawaii
DISCLAIMER: " don't blame me, I'm just a grad student!  "

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

Date: 16 Jan 91 14:48:56 GMT
From: eru!hagbard!sunic!fuug!tuura![e-mail]  (Urban Fredriksson)
Subject: Re: Cameras in 0G, was: Re: MIR Vacation

[e-mail] (Steve Hix) writes:

>In article <[e-mail]>, [e-mail] (H.A.Shaw) writes:
>>
>>     Whats all this about modifications for 0G?  [...]
>> [...] I have around 20,000 slides in my current collection and I've never
>> knowingly lost a shot because of gravity.  What difference does gravity make?
>As I (dimly) recall, space-rating a camera system has little do with
>gravity.  The problems that concerned NASA had more to do with the
>cameras operation in vacuum (outgassing, lubrication, thermal response,
>etc.) than anything else.  Some chemicals outgassing from the camera
>might have been a potential problem from a life-support angle, and
>evaporating lubricants could leave you with a non-functioning paperweight
>just when you didn't need one.

    You will also want all the electrical sections VERY
    isolated, so that there is no chance of a spark
    starting a fire. An other safety-related thing
    is shock-proofing. If I remember correctly the
    camera had to withstand 3 50G shocks, in different
    axes, without any parts becoming separated. The
    limit for keeping it in working condition was 10G.

    Urban

-------------------------------------------------------------------
|    Urban Fredriksson     | "So; you think he deserves to die.   |
|  Nokia Data, Stockholm   |  Those who died, but deserved to     |
| These opinions are mine, |  live, can you give them life back?" |
|  not my organization's.  |            -attributed to Gandalf    |
-------------------------------------------------------------------

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

Date: 16 Jan 91 22:30:50 GMT
From: agate!bionet!uwm.edu!wuarchive!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Magellan Update - 01/16/91


                         MAGELLAN STATUS REPORT
                            January 16, 1991

     The Magellan spacecraft and its radar system continue to perform
nominally after 796 mapping orbits.  All STARCALS (star calibrations) and
DESATS (desaturations) during the past 24 hours were successful.

     No commanding of the spacecraft is planned for today.  The spacecraft
telemetry reported some attitude reference alarms last night.  There was a
"miscompare" between the sun sensors in that the location of the sun as
indicated by the two sensors did not match and/or varied from the reference
value in the on-board computer.  This is believed to be an albedo effect of
Venus, and is being studied further.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 15 Jan 91 20:42:46 GMT
From: agate!linus!linus!kurgen![e-mail]  (Steve Okay W43)
Subject: CRRES observations from Wash. D.C.

Did anybody in the Washington D.C. area get a good glimpse of the CRRES releases?

A bunch of us took up station at the Manassas National Battlefield Park last night
from about 10:50 'till 12:30 and didn't see anything (well, the stars were out, but
nothing even remotely tenuously glowing or otherwise non-stellar. There were about
6-8 of us facing in all different directions, so I don't think it was a problem of not
looking in the right direction.  It was pretty clear out for almost the entire viewing
attempt. Some light pollution, but I didn't feel like taking the hike out to Marshall
or Rt. 81 to get away from all of it. (This could have done it).

If you were anywhere in the D.C. area and saw something, could you mail me and tell me
where and when you were and what you saw?

Thanks,
---Steve
-----------
[e-mail] <---work
[e-mail] <---home

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

End of SPACE Digest V13 #054
*******************