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Subject: SPACE Digest V10 #177

SPACE Digest                                     Volume 10 : Issue 177

Today's Topics:
        Re: NASA Prediction Bulletins:  Space Shuttle
             Re: PowerSat Options
       Payload canister incident to be investigated (Forwarded)
           Galileo and the proposed asteroid flybys
             Re: PowerSat Options
          Re: Space Shuttle SRB exhaust gas makeup.
             Re: Galileo boost from Venus
Payload Canister Mishap Investigation Board: Statement of Activity (Forwarded)
               PowerSat Options
             Re: Cleaning up LEO
             Re: Galileo boost from Venus
          Re: Space Shuttle SRB exhaust gas makeup.
----------------------------------------------------------------------

Date: 24 Oct 89 22:23:22 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu![e-mail]  (R.M. Gronostajski)
Subject: Re: NASA Prediction Bulletins:  Space Shuttle

I hate to clutter the net, but can anyone send me an FTP address
where I can get some satellite tracking software that will run on
an IBM compatible 386 based machine?  Something that has a world map
with pictures of the satellites on it and can use the NASA prediction
bulletin format would be really nice. Thanks in advance.

Rich Gronostajski

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

Date: 25 Oct 89 02:48:10 GMT
From: gem.mps.ohio-state.edu!ginosko!cs.utexas.edu!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: PowerSat Options

In article <[e-mail]> [e-mail] (Steven_Tenney) writes:
>... a powersatellite collecting solar power and passing it
>down to receiving stations either as microwave or even as a laser beam.  I
>knew that microwave energy was a viable option but what about laser energy?

Lasers have the advantage that they are much easier to focus into a tight
beam, and the disadvantage that the power->laser and laser->power conversions
are much more difficult and much less efficient than for microwaves.  They
are also somewhat more subject to attenuation due to weather.  They would
also make much better weapons, which is a potent argument against them if
an unambiguously peaceful device is desired.
--
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry [e-mail]

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

Date: 25 Oct 89 00:57:39 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Payload canister incident to be investigated (Forwarded)


  Karl Kristofferson                               Oct. 23, 1989
  Area Code 407/867-2468

  KSC Release No. 105A-89

  PAYLOAD CANISTER INCIDENT TO BE INVESTIGATED


       Kennedy Space Center Director Forrest S.  McCartney has  ap-
  pointed  a  mishap  investigation  board  to  determine  the cir-
  cumstances surrounding an incident early Saturday which  resulted
  in damage to one of KSC's two payload canisters.

       A  mobile  crane was being used to remove a steel reinforced
  concrete test weight at approximately 2:20 a.m.  Saturday.    The
  weight  was  just  about  clear  of the canister's doors when the
  weight dropped,  striking the canister door as it fell    to  the
  floor of the canister.

       There  were no injuries and an inspection of the canister to
  determine the extent of the damage is underway.

       The temporary unavailability of the damaged canister is  not
  expected  to impact KSC's Space Shuttle operations as the remain-
  ing canister can be scheduled to move payloads between processing
  and pad facilities.

       The  board will be chaired by William G.  Mahoney,  chief of
  the Payload Processing  Division.    Other  members  include  co-
  chairman John D.  Link, STS Payload Operations; Malcolm C. Glenn,
  Safety and Reliability Engineering Division;  Russell  P.  Lloyd,
  Ground Engineering Facilities Division; Michael F. Sumner, Center
  Support Operations;  Bradford P.  Lytle,  Facilities Engineering;
  Kenneth W. Colley,  National STS Operations.   Affiliated members
  are  Alan J.  Guerra,  Industrial Safety Branch,  Safety Advisor;
  Robert G. Young, Payload Projects Management,  Recorder;  Richard
  H.  Mundy, deputy chief counsel, Legal Advisor; George H. Diller,
  Public Affairs Advisor and Wayne R.  Frazier,  NASA  Headquarters
  Advisor.

       The  payload  canister  is  a  container the size of a Space
  Shuttle payload bay which is  used  to  move  integrated  shuttle
  payloads in a controlled environment from the Vertical Processing
  Facility  to the launch pads' payload changeout rooms or from the
  Operations  and  Checkout  Building  to  the  Orbiter  Processing
  Facility.

       The  canisters are 65 feet long,  18 feet wide and 18 feet 7
  inches high.   They have the capability to  carry  vertically  or
  horizontally  processed payloads up to 15 feet in diameter and 60
  feet long,  matching the capacity of a  Space  Shuttle  orbiter's
  payload  bay.    They  can  carry payloads weighing up to  65,000
  pounds.

       The  canister  had  been  used  most  recently  to   conduct
  fit/validation checks at Complex 39's Pad A, now being readied to
  support launch of Columbia on the  STS-32 mission in December.  A
  20-ton  concrete  weight  was used to simulate a payload's weight
  during the Pad A fit/validation check.   The  canister  had  been
  returned to the Vehicle Assembly Building and was in the horizon-
  tal position to permit removal of the test weight, which measures
  approximately 15 feet square and one foot thick.

       Damaged  Canister No.2 had been scheduled to support payload
  operations for the STS-32 mission in December.  We are reschedul-
  ing the activities of Canister No.  1 to support upcoming payload
  flows.

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

Date: 25 Oct 89 02:03:32 GMT
From: agate!shelby!csli![e-mail]  (John Kallen)
Subject: Galileo and the proposed asteroid flybys

Now that Galileo is finally on its way, I start wondering whether the
launch delays the probe suffered affect in any way the planned
asteroid rendezvous (sp?).  Or were the rendezvous cancelled totally
as a consequence of the fuel shortage due to inefficient impulse
thrusters? Personally, I would really like to see images of asteroids
larger than Phobos and Deimos.
_______________________________________________________________________________
 | |   |   |    |\ | |   /|\ | John K{llen
 | |\ \|/ \|  * |/ | |/|  |  | PoBox 11215         "Pappir, pappir, hvi mange
 | |\ /|\  |\ * |\ |   |  |  | Stanford CA 94309   "har thu drapht idag?"
_|_|___|___|____|_\|___|__|__|[e-mail]___________________________

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

Date: 25 Oct 89 02:09:57 GMT
From: munnari.oz.au!murtoa.cs.mu.oz.au![e-mail]  (Gregory KAAN)
Subject: Re: PowerSat Options

in article <[e-mail]>, [e-mail] (Steven_Tenney) says:
>                   Proposed PowerSats
>
> knew that microwave energy was a viable option but what about laser energy?
> Steve Tenney

The laser boys keep telling us that by using lasers instead of microwave
transmission, we would get less spillage and therefore, greater efficiency
and lower the safety risks.

Unfortunately, I have yet to read about a high efficiency ( > 50 % )
laser or photoconverter so to me, laser power transmission would offer
at best about 9% dc-to-dc efficiency (using 30% efficiency for the laser
and the photoconverter which I suspect is generous).
This also ignores attenuation within the atmosphere which can reach
100% in bad weather conditions.

On the other hand, microwave transmission with a dc-to-dc efficiency of
85% was demonstrated at Goldstone back in the 70's (over a range of about
10 km I think). Using a frequency of 2.45 GHz, attenuation due to atmospheric
effects is not a problem (I studied the problem for my final year thesis).

The big problem is putting the Space Power Satellites up into orbit.
Just about all other technical problems have been solved.

Greg Kaan.

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

Date: 24 Oct 89 18:45:02 GMT
From: milton![e-mail]  (Stephen Milton)
Subject: Re: Space Shuttle SRB exhaust gas makeup.

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>     Does it contain hydrogen oxide?
>
>I.e., water?  Yes, among other things.  Lots of other things.  SRB fuel,

technically, water is not hydrogen oxide, its dihydrogen oxide.  Were you
referring to this, or to some extremely odd form.

[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[]Stephen M. Milton, Operator/Consultant, UCS, University of Washington []
[]                 '[e-mail]'                    []
[]Lifetime Goals: Local Autonomous Anarchy, and A Good Beef on Rye Sand.[]
[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]

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

Date: 24 Oct 89 16:35:41 GMT
From: gem.mps.ohio-state.edu!ginosko!shadooby!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Galileo boost from Venus

In article <[e-mail]> [e-mail] (Brian Holtz) writes:
>Let me ask this again:
>If the attraction between Galileo and, say, Venus is the same
>when Galileo is coming and going, how does the encounter speed
>up the craft?  Does it have something to do with the fact that it's
>passing Venus as they both orbit the the sun?

Sigh... for the Nth time... yes, it has a lot to do with the fact that
Venus orbits the Sun.  Galileo gains no velocity *with respect to
Venus*.  With respect to the Sun, that's different.

I'm indebted to David Navas for this analogy:  if you bounce a ball off a
car coming towards you at 60 MPH, it comes back a lot harder than if you
bounce it off a stationary car.  Even though, from inside the car, either
way the ball bounces back at about the velocity it arrived at.
--
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry [e-mail]

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

Date: 25 Oct 89 00:56:39 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Payload Canister Mishap Investigation Board: Statement of Activity (Forwarded)


  October 24, 1989



  Payload Canister Mishap Investigation Board:
  Statement of Activity

       The board met this morning to review progress in receiving
  the material requested to support the investigation.  The board
  then reconvened in High Bay 4 of the Vehicle Assembly Building to
  examine the mobile crane involved in the mishap.  They also
  inspected damage to the payload canister to determine what clues
  it provides as to why the event occurred.  During the afternoon
  the board prepared questions which may be asked of the personnel
  who were present during the mishap.  Witness interviews will
  begin late this afternoon and continue all day on Wednesday.


  George H. Diller
  Public Affairs Board Representative

  Approved for release by  William G. Mahoney,
  Board Chairman

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

Date: 24 Oct 89 15:19:52 GMT
From: hp-sdd!hp-pcd!hpcvia![e-mail]  (Steven_Tenney)
Subject: PowerSat Options


                  Proposed PowerSats

Please forgive a novice's ignorance on this subject but I thought I read
somewhere about a powersatellite collecting solar power and passing it
down to receiving stations either as microwave or even as a laser beam.  I
knew that microwave energy was a viable option but what about laser energy?

Thank you for any information on this topic.

Steve Tenney

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

Date: 24 Oct 89 16:10:27 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu!radio.astro!helios.physics![e-mail]  (Prof. A. Griffin)
Subject: Re: Cleaning up LEO

Disclaimer: I am NOT professor Griffin. If you use "F", please check the
attribution against the signature.

In article <[e-mail]> [e-mail] I write:
>   According to some calculations I made this afternoon, and which I'm
>still having trouble believing,
>
   I found the mistakes. Slipped a decimal point or two when plugging
numbers into my equations. Sorry about that.

>   The scenario I used was a mettalic flake 1mm in diameter, and 0.1mm
>thick, in a circular orbit 300km above the surface of the earth. It turns
>out that the photon pressure on the flakes lowers the perigee of the orbit
>to 100km, at which time it can be said to be braking in the atmosphere and
>out of our way, in only 1.6 hours of exposure to the beam, or roughly two
>days, where the orbit passes into the beam every ninety minutes for four
>minutes.
>
   The correct value is 2 days in the beam, or roughly a month and a half
of real time.

>   The same flake in a Clarke orbit would enter atmosphere after about
>twenty months.
>
   Well, twenty-five to thirty months.

>   The advantage to this approach is that it works best on small objects. A
>communication satellite would suffer a delta-v of only about 1m/s, which I
>presume is within the tolerance of the onboard thrusters to compensate.
>
   1.5 m/s, should still be all right.

--
 Christopher Neufeld....Just a graduate student  |  "Scotty..now _would_
 [e-mail]               | be a good time!"
 [e-mail]              |   - Pavel Chekov
 "Don't edit reality for the sake of simplicity" |

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

Date: 24 Oct 89 13:51:59 GMT
From: ns-mx![e-mail]  (Douglas W. Jones,201H MLH,3193350740,3193382879)
Subject: Re: Galileo boost from Venus

From article <[e-mail]>,
by [e-mail] (Brian Holtz):
> If the attraction between Galileo and, say, Venus is the same
> when Galileo is coming and going, how does the encounter speed
> up the craft?  Does it have something to do with the fact that it's
> passing Venus as they both orbit the the sun?

The velocity of Galileo (or a rock, the dynamics are the same) approaching
Venus is the same as the velocity leaving Venus, measured with respect to
Venus (and at the same distance).  The trick is to arrange the orbit so that
the rock leaves Venus in an orbit tangent to Venus's orbit after having
arrived from some other direction.  The result is that (from the Sun's point
of view) the rock picks up speed.

Here's an example orbital strategy that would gain energy from encounters
with some planets:

Launch a rock from Earth with enough energy that it leaves Earth at its
aphelion and falls towards the Sun.  It rushes by Venus on its way to its
perihelion well inside Venus's orbit, passing behind Venus on its way.
Leaving Venus, it is in a new orbit with perihelion tangent to Venus's orbit
and aphelion well outside Earth's orbit.

Our rock now crosses Earth's orbit, passing just behind it so it's orbit
changes again.  Earth slings the rock into a new orbit with perihelion
tangent to Earth's orbit and aphelion way out yonder.

The above strategy is simpler than the Galileo strategy, which (as I
understand it) involves two Earth encounters.

                    Douglas Jones
                    [e-mail]

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

Date: 24 Oct 89 22:27:43 GMT
From: agate!typhoon.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re: Space Shuttle SRB exhaust gas makeup.

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>I.e., water?  Yes, among other things.  Lots of other things.  SRB fuel,
>if I recall correctly, is ammonium perchlorate (NH4ClO4) plus a dash of
>aluminum powder for extra heat, a demitasse of synthetic rubber for
>mechanical strength, and an assortment of minor odds and ends to control
>burn rate and such.  So the exhaust will contain water, alumina (Al2O3)
>particles, carbon dioxide (from the rubber), and a witches' brew of
>nitrogen and chlorine compounds and partially burnt ickiness.

    A _dash_ of aluminum???  The majority of the thrust is achived
by the aluminum component of the fuel !
    The actual materials are Ammonium Perchorate, Aluminum powder, PVC
binder and extra bits to stabilize.  It's about 99% those three.
    Yes, the exhaust if icky.  suprise :)


****************************************
George William Herbert  UCB Naval Architecture Dpt. (my god, even on schedule!)
[e-mail]  [e-mail]
----------------------------------------

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

End of SPACE Digest V10 #177
*******************