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Subject: SPACE Digest V11 #81

SPACE Digest                                      Volume 11 : Issue 81

Today's Topics:
                 Re: Beanpole
            Re: What happened to Pegasus?
       Re: Fun Space Fact #1: Launcher Development Costs (long)
               Laser Satellites
              Re: Power Sources
              Voyager Update - 02/23/90
       Re: NASA Headline News for 02/22/90 (Forwarded)
               Re: GIF pictures
            Re: Galileo Update - 02/16/90
----------------------------------------------------------------------

Date: 24 Feb 90 08:28:34 GMT
From: snorkelwacker!usc!brutus.cs.uiuc.edu!jarthur![e-mail]  (Robert Knop)
Subject: Re: Beanpole

In article <[e-mail]> [e-mail] (Daniel Rothman) writes:
>Has anybody out there heard rumors of a beanpole [ie an earthbound structure
>extending to low orbits]?  A friend of mine in polymers mentioned that new
>ceramics could possibly withstand the shearing loads on such a structure.

Read "The Web Between The Worlds" by Charles Sheffield.  Granted, that is
Science Fiction, not quite what you are after, but it is a very interesting
(and seemingly technically plausible) book.

-Rob Knop [e-mail]

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

Date: 25 Feb 90 01:05:13 GMT
From: cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: What happened to Pegasus?

In article <[e-mail]> [e-mail] writes:
>Does anyone know what's been going on with the Pegasus launcher
>by Orbital Sciences Corp. lately? Were'nt they supposed to launch
>soon?

They've had various minor problems, notably in their electronics, that
have slowed things down.  Last I heard, the third captive-carry test
had gone tolerably well and a launch date sometime in March had been
pencilled in.
--
"The N in NFS stands for Not, |     Henry Spencer at U of Toronto Zoology
or Need, or perhaps Nightmare"| uunet!attcan!utzoo!henry [e-mail]

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

Date: 23 Feb 90 23:00:21 GMT
From: zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!turnkey!orchard.la.locus.com!prodnet.la.locus.com![e-mail]  (Todd Johnson)
Subject: Re: Fun Space Fact #1: Launcher Development Costs (long)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

 [ I don't have numbers on hand right now, but G loads were quite low -- you
 [ could launch people with it if you had very small people. :-)  It was on
 [ the order of 5G maximum.  Payload to orbit was something like 20kg, but
 [ launch frequency more than made up for the small size of the individual
 [ loads.

20 kg? If that's not a typo, such a low load would probably require
on orbit assembly (worse, tugging stuff up to GEO or higher orbits
would probably be required which means either a refuellable tug
or a throwaway transfer vehicle). It's not clear to me that you've
saved anything with such a low payload. Are you sure it wasn't more
like 20,000 kg? or 2,000 kg?

    <todd>
--
lcc![e-mail]
{randvax,sdcrdcf,ucbvax}!ucla-se!lcc!todd
{gryphon,turnkey,attunix,oblio}!lcc!todd

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

Date: 24 Feb 90 19:14:00 GMT
From: snorkelwacker!usc!zaphod.mps.ohio-state.edu!rpi!rpitsmts![e-mail]  (Commander Krugannal)
Subject: Laser Satellites


       err, make that spacecraft.

      I do not have figures, but I do know that there is SERIOUS
   work being done on craft of this nature. Here at RPI
   Dr. Leik Myrabo is working on the Apollo Lightcraft Project.
   The design of the manned portion is based on the extended 5 man
   Apollo capsule designed for Skylab rescues.
      There are two designs, one is based on the laser being benith
   the craft, and the other is spaced based.
      In addition to the ALP, he has looked into building aircraft
   and such based on the concept. The largest problem according to
   him was tracking. (At the time he and I were discussing the
   concept of a highly manevourable fightercraft that could
   excute 10+g moves for a split second. (Within human tolerence
   for such short duration, but effective enough to move the
   craft instaneously in any directio to avoid missiles and the
   like.). )
      I am not sure where the statues of the ALP is currently, but
   I believe at last report they were planning on buildin a scale
   model and testing it this summer. Much of the windtunnel work
   has been done here on campus or at other sights. (Though I believe
   we have the only Hypersonic shock tunnel on the east coast). The
   scale model would actually be used to test the laser and the
   focusing mechanism.
      In the current design, the craft has a form of a mirror
   (depending if space based laser or ground based laser) that
   focuses the beam to a point at the bottom of what looks a lot
   like an aerospike. This superheats the air until it explodes.
   The laser is defocused or shut of for a split second to allow
   a new air envelope to form and then refocused. This cycle is
   repeated. This is done until the air density is too thin. In
   this case an on board supply of fuel. (In some scenarios water
   since it is cheap!) is put into the stream and this provides
   the fuel.
      The current design has been test I believe up too supersonic
   speeds and current theory holds that the 'engine' will work
   through the hypersonic regime and into the rocket regime.
   (The rocket regime refering to the use of water or other fuel.)
     I have greatly simplified the operation of the engine since it
   has to tune itself depending on airspeed and altitude, but the
   basic design is described.

   [e-mail]

   Disclaimer: Why do I need one? everyone else has one!

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

Date: 23 Feb 90 15:39:50 GMT
From: zaphod.mps.ohio-state.edu!uwm.edu!cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Kieran A. Carroll)
Subject: Re: Power Sources

[e-mail] (Andrew J Hasara) writes:
>
>    I was wondering what information you fellow netter may have concerning
> power storage systems.  I am trying to find out about power systems that
> would work (with close to the same power output) in both an accelerating
> and non-accelerating environment.  I am trying to optimize for material cost,
> energy density, power output, and amount of hassle reguired to obtain and
> maintain the system.
>    I have preferences for low hassle, high output systems.  Rechargability
> is welcome, but not required.  Hopefully, nothing along the lines of "In X
> number of years we'll be able to. . .".  BTW, Solar power is out because of
> other restrictions not mentioned.
>    In effect, I am trying to store 7*10^12 Joules of electrical energy in a
> couple tons.

Ref: r. Michael Hord; "CRC Handbook of Space Technology:
Status and Projections"; CRC Press, Boca Raton, Florida, 1985.

The highest energy density to be expected from "primary batteries"
comes from Li/SOCl2 batteries. These currently can store 200
W-hr/kg, and are estimated to soon be able to store 300 W-hr/kg
of power. That gives you about 2e9 Joules of storage in a couple of
tons of batteries. Note: their lifetime is currently about 3 years,
with 8 years estimated as possible.

For comparison, Ag/Zn batteries have about half the specific storage
capacity (160-180 W-hr/kg). The numbers for "secondary batteries"
are 30-45 for Ni/H2, and 15-30 for Ni/Cd.

Looks like you're out of luck on the chemical battery front. What about
nuclear power? Radioisotope thermoelectric generators (RTGs -- don't
let the Christics hear us! :-) apparently produce from 5-8 W/kg. Thus,
a couple of tonnes of them would produce about 10-16 kW. In order to
get 7*10e12 Joules out of these babies, you'd have to use them for
about 14-22 years (this estimate ignores the drop-off of power with
time, as the plutonium in the RTGs gets used up). For comparison, solar
arrays would have gotten you about 35-200 W/kg, presumably in Earth
orbit.

Fuel cells (H2/O2) can apparently produce about 110-130 W/kg, but I
don't think that that figure includes the mass of the reactants used
(i.e. it's just the mass of the cell). There is a figure quoted for
"Energy density mission" of 400-1400 kW-hr/kg; assuming that this
includes the mass of the reactants, that would give you about 3e12 to
1e13 J from 2 tonnes of them. Looks like these might be what you're
looking for (although again it'd take you several years to get the
energy out).

For all of these systems, don't forget the associated thermal problems.
Conversion of energy from its stored form to electricity is never 100%
efficient, so waste heat will be generated; you'll have to dissipate
this somehow, and your radiators will likely add mass to the power
system.

Three technologies not covered in the reference book:

- Nuclear reactors (maybe your best bet)
- Antimatter (not really a current technology; wait for it...)
- Cold Fusion (looks like it'll have at best a pretty low
  specific power, but it's a bit early to tell :-)
--

     Kieran A. Carroll @ U of Toronto Aerospace Institute
     uunet!attcan!utzoo!kcarroll [e-mail]

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

Date: 24 Feb 90 04:44:01 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Voyager Update - 02/23/90


            Voyager Mission Status Report
              February 23, 1990

                  Voyager 1

     On February 9, AACS Gyros A and B were turned on and initialized.
Spacecraft performance for the activity was nominal. The following activities
were supported on February 12: an ASCAL, recording of one frame of high-rate
PWS data, and a TLC test. High-rate UVS observations were conducted on BW
Vulpeculae (February 13) and lambda Eridani (February 14). Most of the data
were not observed in real-time due to no large-aperture coverage being
available.

     On February 13, the ISS narrow and wide angle cameras were turned on and
the VPLANETS sequence was executed. It was necessary for the Voyager 1
spacecraft to roll to a new lock star (Peacock) in order to acquire the
Jupiter, Earth, and Venus images. Following the sequence, the wide and narrow
angle cameras were turned off.  Only the camera turn on and a -318.2x roll
turn to Peacock as the roll axis celestial reference were observed in real
time due to a lack of Deep Space Network (DSN) station availability.  The
VPLANETS sequence was programmed to record images of Neptune, Uranus, Saturn,
Mars, Jupiter, Earth, Venus, and various star fields.  A total of 21 narrow
angle and 39 wide angle images were recorded.  The AACS scan platform pointing
was 1x from the Sun in the final images taken of Venus.  Playback of these
images is scheduled for 3/16, 3/20, 3/23, and 3/27.

     Following the sequence execution and return to CR-5 data mode, all
observable spacecraft parameters appeared to be nominal.  This was the last
planned use of the AACS DSSCAN patch and ISS cameras.

     On February 15, the X-Band TWT was commanded to the low power mode and
the Bay 1 heater was turned on.


                  Voyager 2

     Voyager 2 continues to collect routine cruise science data. On February
12, one frame of high-rate PWS data was recorded and a high-rate UVS
observation was conducted on Feige 7. Neither of these activities were
observed in real-time due to lack of DSN station support.

     On February 14, an RFSCMD (threshold) test was executed by the DSN station
in Goldstone, California. Due to procedural errors during the test, the test
was not completely successful. Procedural changes will be made before the next
attempt of a RFSCMD test.  This was the first time that this particular test
sequence had been attempted.

     Spacecraft performance for all the sequenced activity during this
report period has been nominal.


 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

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

Date: 23 Feb 90 21:02:10 GMT
From: ox.com!itivax!vax3![e-mail]  (Allen W. Sherzer)
Subject: Re: NASA Headline News for 02/22/90 (Forwarded)

In article <[e-mail]> [e-mail] (Feulner ... Matthew Feulner) writes:
>>Arianespace will launch two Japanese satellites from Kourou, ...

>Anyone have information on the launch failure?  I just heard it from
>a friend who heard it on the news.

I saw it on CNN. It blew up about 2 min. into the flight. No reasons
given and all Airan launches are on hold.

  Allen

----------------------------------------------------------------------------
| Allen W. Sherzer     | Cthulhu for President -                           |
|  [e-mail]         | If you're tired of choosing the LESSER of 2 evils |
----------------------------------------------------------------------------

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

Date: 23 Feb 90 23:12:04 GMT
From: eru!luth!sunic!tut!kannel![e-mail]  (Kauto Huopio)
Subject: Re: GIF pictures

There is a reasonably good collections of space-oriented GIFs at
funic.funet.fi
in directories
disk1/pub/misc/gif/pics/satpics
and
dis1/pub/misc/gif/pics/space

Enjoy!

Kauto Huopio, GIF Manager #2 at funic.funet.fi

PS: You can reach all GIF maintainers via [e-mail]
We have also a GIF mailing-list [e-mail]. If you would like to join,
do NOT send mail to either of these addresses, but to
[e-mail]

--
****************** Kauto Huopio ([e-mail]) **********************
*US Mail: Kauto Huopio, Punkkerikatu 1 A 10, SF-53850 Lappeenranta, Finland *
*Project: Learn some GNU Emacs first.. :-)                                  *
*****************************************************************************

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

Date: 23 Feb 90 19:45:47 GMT
From: psuvm![e-mail]  (Zaphod Beeblebrox)
Subject: Re: Galileo Update - 02/16/90

In article <[e-mail]>, [e-mail] (Ron Baalke) says:
>
>     As of noon Friday, February 16, 1990, the Galileo spacecraft is
>36,987,350
>miles from the Earth, 2,151,150 miles from Venus and is traveling at a
>Heliocentric velocity of 90,063 miles per hour. Perihelion will occur on
>February 25. Roundtrip light time is 6 minutes, 30 seconds.

Does anyone out there have the data for Galileo probe when it was first
placed in orbit..  .like altitude. . .velocity. . .and the stats
from the inertial upper stage rocket (did they finally decide to use
that?)  . .

"I'll give it due reflection. . .based on the evidence. . I, the jury"
RUSH, Show Don't Tell

Mark. . .MXP122 at psuvm.psu.edu

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

End of SPACE Digest V11 #81
*******************