Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_2/V16NO252.TXT

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Date: Tue,  2 Mar 93 10:54:00
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #252
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue,  2 Mar 93       Volume 16 : Issue 252

Today's Topics:
                          forwarded message
                Galileo Earth-Moon Animation (2 msgs)
                    Help needed for Delta Clipper
                   Query on sun synchronous orbits
                     SOLAR gravity assist?  NOPE.
                      Space Calendar - 01/28/93
                             SSF Resupply
           SSF Resupply (Was Re: Nobody cares about Fred?)

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

Date: 1 Mar 93 02:44:54 GMT
From: Adrian Hassall Lewis <[e-mail]>
Subject: forwarded message
Newsgroups: sci.space

[e-mail] (BAIRD) writes:

>Another idea:
>The ice is launched as a sphere of, say, 1m diameter, and is
>accurately aimed at a long, narrowly tapered conical hole in the lunar
>surface. The cone openning is about 10m in diameter, is heavily lined
>with steel, and sunk into solid bedrock for strength. The cone angle is
>sufficiently small that the ice sphere, coming in parrallel to the cone
>axis, will not dent the steel wall upon grazing angle impact. The ice,
>however, may at that point disinitigrate into ice cubes. The cone is used
>to inject the ice into a steel tube somewhat over 1m in diameter which is
>also sunk into the bedrock for strength. The tube is bent to give a radius
>of curvature of about 100 m. The centripital acceleration of the ice fragments
>will be on the order of 1000 g's. The tube can be built to withstand this
>since ice on steel has very little abrasiveness and the pressure is
>tolerable for steel in bedrock. The ice, however, will melt and vaporize
>from the friction. The tube can curve back on itself so that the H2O
>can race around in a loop until its kinectic energy is expended.
>Within the first second or less of injection, a vacuum tight gate valve
>closed off the conical injectors throat so that the water vapor doesn't
>escape.  The tube is kept warm enough to prevent condensation while
>the water vapor is pumped out of the tube with a condensation (cryo)
>pump to slake the thirst of the colonists.

>                          Edward Ruden

finding bedrock on the moon is apparently something of a problem :-)

ajax

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

Date: Mon, 1 Mar 1993 01:03:52 GMT
From: Leigh Palmer <[e-mail]>
Subject: Galileo Earth-Moon Animation
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]> Ron Baalke,
[e-mail] writes:
>Conversion to other formats is already underway.  Also, someone notified
me
>that they were able to run the animation under Quicktime.

The rest of us with Quicktime would like to know how to accomplish that
format transformation.

Leigh

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

Date: 1 Mar 1993 02:43 UT
From: Ron Baalke <[e-mail]>
Subject: Galileo Earth-Moon Animation
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]>, Leigh Palmer <[e-mail]> writes...
>In article <[e-mail]> Ron Baalke,
>[e-mail] writes:
>>Someone notified me
>>that they were able to run the animation under Quicktime.
>
>The rest of us with Quicktime would like to know how to accomplish that
>format transformation.

Run Quicktime on it as you would any other Quicktime animation.  It will
prompt you if you want to convert the animation.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | If you don't stand for
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | something, you'll fall
|_____|/  |_|/       |_____|/                     | for anything.

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

Date: 1 Mar 93 02:27:14 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Help needed for Delta Clipper
Newsgroups: sci.space,talk.politics.space

VP Gore is meeting with his science advisor John Gibbons. They are looking
at technologies to invest in to help with defense conversion. The SDIO
Single Stage Rocket Technology program and the Delta Clipper vehicle
are naturals for this. They will be finalizing this by march 12.

Please FAX a letter (see number below) to VP Gore and/or call his
office. Ask them toully fund the SDIO O SSRT program. They need $50
million to do requirements specification but with $100 million they
would have enough to build prototypes and answer almost all open
questions.

The current budget only has $5 million for this program which is not
enough. Unless we convince the administration and Congress to add at
least $45 million more, the Delta Clipper program will end this August.

Please don't delay. This is a critical time for a vehicle which has
a good chance of offering cheap routine access to space.

Gore's address is:

VP Al Gore
1600 Pennsylvania Ave
Washington DC 20500

His phone numbers are:

[phone] (voice)
[phone] (FAX)

A faxed letter will have the most impact.

  Allen


--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------107 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 1 Mar 1993 03:23:23 GMT
From: [e-mail]
Subject: Query on sun synchronous orbits
Newsgroups: sci.space

Can anybody email me an explanation of what is meant by
a sun-synchronous orbit is?

Thanks.


=======================================================================
| Bill                       ||My whole life long, I've sharpened my  |
| ([e-mail])  ||sword, and now face to face with death |
| C. O. P.,  U. N. M.        ||I unsheathe it, and lo, the blade is   |
| Albuquerque, N. M. USA     ||broken. Alas.   - Dairin Soto          |
=======================================================================

--
=======================================================================
| Bill                       ||My whole life long, I've sharpened my  |
| ([e-mail])  ||sword, and now face to face with death |
| C. O. P.,  U. N. M.        ||I unsheathe it, and lo, the blade is   |

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

Date: 1 Mar 93 00:29:59 GMT
From: Henry Spencer <[e-mail]>
Subject: SOLAR gravity assist?  NOPE.
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] (Robert M. Unverzagt) writes:
>>     In addition to a direct solar gravity assist for a Pluto, there might
>>be some benefit in carrying propellant deep into the energy well of the sun,
>>and burning it there to provide a boost to Pluto.  Is anyone familiar enough
>>with the calculations to estimate what the benefit might be?
>
>Sure, I'll take a stab at it.  The delta-v for a direct injection
>to Pluto is about, er, 38,771 ft/sec...
>...If we wanted to do a close pass of the sun, we
>could add that 38,771 IN THE OPPOSITE DIRECTION OF EARTH'S MOTION
>AROUND THE SUN to give us a periapsis closer to the sun...
>Do I need to go any further to show that there is no net benefit
>of doing this?  Maybe I do -- obviously more delta-V will have to
>be added at closest approach to raise apoapsis to Pluto's orbital radius...
>Can the person who originally claimed a benefit for this please
>explain again? ...

Sure you need to go further -- one data point does not a graph make,
much less a proof.  Especially when you're disagreeing with no less
an authority than Hermann Oberth.

However, I can save you the effort. :-)  A pretty algebra problem...
a lot of the variables eventually drop out, if you persist.

It turns out that the crucial question is:  do you want to reach more
than solar escape velocity, and if so, how much more?  If the desired
velocity at infinity is less than sqrt(2) times the orbital velocity
of the circular orbit you start from, then dipping closer to the Sun
hurts performance.  But if you want v_infinity greater than that,
then lowering your perihelion as much as you can, and doing the main
burn at perihelion, is a net win.  The win can be large, if you want
lots of v_infinity and you can survive a very low perihelion.

To be exact... if i = v_infinity/v_circular and p = r_perihelion/r_circular
(note that v_circular = sqrt(G * M_sun / r_circular)), then the ratio of
total delta-v for the gravity-well maneuver to total delta-v for doing
it in one burn is:

sqrt(i^2 + 2/p) + 1 - sqrt(2 + 2/p)
-----------------------------------
    sqrt(i^2 + 2) -1

It is therefore obvious :-) that if i > sqrt(2), the ratio is less than 1.

This is a general result, it's not restricted to the heliocentric case.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: 28 Feb 93 23:59:24 GMT
From: Ron Baalke <[e-mail]>
Subject: Space Calendar - 01/28/93
Newsgroups: sci.space,sci.astro,sci.space.shuttle,alt.sci.planetary

     Here's the latest Space Calendar.  Please send any updates or corrections
to Ron Baalke ([e-mail]).  Note that launch dates are
subject to change.

     The following people made contributions to this month's calendar:

        o Mike Boschat, maximum times and solar longitudes of all meteor
          showers.
        o Doug Ramsay, updated UHF-1 Atlas Launch date (03/11/93).


                          =========================
                               SPACE CALENDAR
                              January 28, 1993
                          =========================

* indicates change from last month's calendar

January 1993
* Jan 28 - SCD-1 Pegasus Launch (Brazil)
  Jan 30 - Soyuz TM-15 Lands (Soviet)

February 1993
  Feb ?? - ALEXIS Pegasus Launch
  Feb ?? - Consort 6 Starfire Launch
  Feb 01 - 35th Anniversary, Explorer 1 Launch (1st U.S. Satellite)
* Feb 02 - Galaxy 4 Ariane Launch
  Feb 08 - Mars Observer, 2nd Trajectory Correction Maneuver (TCM-2)
  Feb 12 - Astro-D M3S-2 Launch (USA/Japan)
  Feb 18 - Jules Verne's 165th Birthday
  Feb 19 - Copernicus' 520th Birthday
  Feb 25 - STS-55, Columbia, Spacelab Germany (SL-D2)

March 1993
  Mar ?? - Hispasat 1B & Insat 2B Ariane Launch
  Mar ?? - DFH-3 Long March 2E Launch (China)
  Mar ?? - GPS/SEDS-1 Delta II Launch
  Mar 01 - Ulysses, 3rd Opposition
* Mar 11 - Galileo, 10 RPM Spinup Test
* Mar 11 - UHF-1 Atlas Launch
  Mar 18 - Mars Observer, 3rd Trajectory Correction Maneuver (TCM-3)
* Mar 23 - STS-56, Discovery, Atmospheric Lab for Applications and Science
           (ATLAS-2)
  Mar 31 - Commercial Experiment Trasporter (Comet) Conestoga Launch

April 1993
  Apr ?? - First Test Launch of the DC-X
  Apr 06 - 20th Anniversary, Pioneer 11 Launch (Jupiter & Saturn Flyby Mission)
  Apr 19 - Venus/Moon Occultation, Visible from North America
  Apr 22 - Lyrid Meteor Shower (Maximum: 03:00 UT, Solar Longitude 32.1 degrees)
* Apr 28 - STS-57, Endeavour, European Retrievable Carrier (EURECA-1R)

May 1993
  May ?? - Advanced Photovoltaic Electronics Experiment (APEX) Pegasus Launch
  May ?? - Radcal Scout Launch
  May ?? - Astra 1C Ariane Launch
  May ?? - GPS/PMQ Delta II Launch
  May 04 - Galileo Enters Asteroid Belt Again
* May 04 - Eta Aquarid Meteor Shower (Maximum: 21:00 UT, Solar Lon: 44.5 deg)
  May 21 - Partial Solar Eclipse, Visible from North America & North Europe
  May 25 - Magellan, End of Mission?

June 1993
  Jun ?? - Temisat Meteor 2 Launch
  Jun ?? - UHF-2 Atlas Launch
  Jun ?? - NOAA-I Atlas Launch
  Jun 04 - Lunar Eclipse, Visible from North America
  Jun 14 - Sakigake, 2nd Earth Flyby (Japan)
  Jun 22 - 15th Anniversary of Charon Discovery (Pluto's Moon) by Christy

July 1993
  Jul ?? - MSTI-II Scout Launch
  Jul 01 - Soyuz Launch (Soviet)
  Jul 08 - Soyuz Launch (Soviet)
  Jul 09 - STS-51, Discovery, Advanced Communications Technology Satellite(ACTS)
  Jul 14 - Soyuz TM-16 Landing (Soviet)
  Jul 21 - Soyuz TM-17 Landing (Soviet)
* Jul 28 - S. Delta Aquarid Meteor Shower (Maximum: 19:00 UT,
           Solar Longitude 125.8 degrees)
  Jul 29 - NASA's 35th Birthday

August 1993
  Aug ?? - ETS-VI (Engineering Test Satellite) H2 Launch (Japan)
  Aug ?? - GEOS-J Launch
  Aug ?? - Landsat 6 Launch
  Aug ?? - SeaWIFS Launch
  Aug ?? - ORBCOM FDM Pegasus Launch
  Aug 08 - 15th Anniversary, Pioneer Venus Orbitor 2 Launch
  Aug 09 - Mars Observer, 4th Trajectory Correction Maneuver (TCM-4)
* Aug 12 - N. Delta Aquarids Meteor Shower (Maximum: 07:00 UT,
           Solar Longitude 139.7 degrees)
* Aug 12 - Perseid Meteor Shower (Maximum: 15:00 UT,
           Solar Longitude 140.1 degrees)
  Aug 24 - Mars Observer, Mars Orbit Insertion (MOI)
* Aug 25 - STS-58, Columbia, Spacelab Life Sciences (SLS-2)
  Aug 28 - Galileo, Asteroid Ida Flyby

September 1993
  Sep ?? - SPOT-3 Ariane Launch
  Sep ?? - Tubsat Launch
  Sep ?? - Seastar Pegasus Launch
  Sep ?? - EPOT-3/ASAP-4 Ariane Launch

October 1993
  Oct ?? - Intelsat 7 F1 Ariane Launch
  Oct ?? - SLV-1 Pegasus Launch
  Oct ?? - Telstar 4 Atlas Launch
* Oct 22 - Orionid Meteor Shower (Maximum: 00:00 UT,
           Solar Longitude 208.7 degrees)

November 1993
  Nov ?? - Solidaridad Ariane Launch
  Nov 03 - 20th Anniversary, Mariner 10 Launch (Mercury & Venus Flyby Mission)
  Nov 03 - S. Taurid Meteor Shower
  Nov 04 - Galileo Exits Asteroid Belt
  Nov 06 - Mercury Transits Across the Sun, Visible from Asia, Australia, and
           the South Pacific
  Nov 13 - Partial Solar Eclipse, Visible from Southern Hemisphere
* Nov 10 - STS-60, Discovery, SPACEHAB-2
* Nov 17 - Leonids Meteor Shower (Maximum: 13:00 UT,
           Solar Longitude 235.3 degrees)
  Nov 28-29 - Total Lunar Eclipse, Visible from North America & South America

December 1993
  Dec ?? - GOES-I Atlas Launch
  Dec ?? - NATO 4B Delta Launch
  Dec ?? - FAST Scout Launch
  Dec ?? - TOMS Pegasus Launch
  Dec ?? - DirectTv 1 & Thiacom 1 Ariane Launch
  Dec ?? - ISTP Wind Delta-2 Launch
  Dec ?? - STEP-2 Pegasus Launch
  Dec 01 - Mars Observer, Mapping Orbit Established
* Dec 02 - STS-61, Endeavour, Hubble Space Telescope Repair
  Dec 04 - SPEKTR-R Launch (Soviet)
  Dec 05 - 20 Anniversary, Pioneer 10 Launch (Jupiter Flyby Mission)
  Dec 08 - Mars Observer, Mars Equinox
* Dec 14 - Geminids Meteor Shower (Maximum: 00:00 UT,
           Solar Longitude 262.1 degrees)
  Dec 20 - Mars Observer, Solar Conjunction
* Dec 23 - Ursids Meteor Shower (Maximum: 01:00 UT,
           Solar Longitude 271.3 degrees)

January 1994
* Jan 02 - Mars Observer, End of Solar Conjunction
* Jan 22 - Mars Observer, Mapping Begins
* Jan 24 - Clementine Titan IIG Launch (Lunar Orbiter, Asteroid Flyby Mission)
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/  |_|/       |_____|/                     |

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

Date: 1 Mar 93 03:20:54 GMT
From: Bruce Dunn <[e-mail]>
Subject: SSF Resupply
Newsgroups: sci.space

> Pat writes:
>
>   My point was given SSF was going to produce waste CO2,  you could carry
> up a  small supply of Hydrogen,  and convery CO2 -> CH4.  then with the
> released oxygen run thrusters.  although, if the fuel cells produce water,
> you might crack that electrically, and then have all your feedstocks.


        No need to bother with all this.  Instead of using electrical power
to store energy in chemical bonds for the purpose of releasing the energy
later in a motor, just apply the electrical energy directly.  Heat the CO2 in
a resistojet, and exhaust it through a nozzle.  Specific impulse is not
impressive, but resistojets in the sizes needed are small and light weight,
and all the electrical power applied ends up in the exhaust jet, which is
more than can be said for any scheme involving reforming molecules.
        Disadvantages of this scheme are the need for power, and the fact
that probably there is probably not enough CO2 generated each year to cover
the reboost requirements.

--
Bruce Dunn    Vancouver, Canada   [e-mail]

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

Date: 28 Feb 93 16:42:31
From: Steinn Sigurdsson <[e-mail]>
Subject: SSF Resupply (Was Re: Nobody cares about Fred?)
Newsgroups: sci.space

In article <1mpa9h$[e-mail]> [e-mail] (George William Herbert) writes:

   References: <[e-mail]> <[e-mail]> <[e-mail]>
   NNTP-Posting-Host: soda.berkeley.edu
   Summary: You can't do accounting that way...

   In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
   >This is false; you repeatedly assume that the cost per pound is the
   >total operation cost+amortised cost divided by pounds flown; it is
   >no such thing - if NASA stopped in its tracks and flew nothing
   >it would still cost several billion per year.

   If that happened it wouldn't be a space program, it would be
   a jobs welfare program for space engineers and technicians.

Of course some argue that that is exactly what it is... :-(

   As it is a space program, a responsible accounting methodology is
   to sum its operations costs and divide by payload mass flown.
   If it stops being a space program then it stops getting treated
   as one for accounting purposes.  Until then, it's irresponsible
   not to account that way.

Here I disagree. NASA is not FedEx-in-space, it is a development
and research agency. It's purpose is more than delivering gross
weight to orbit. This is also why I think the high-end numbers
for STS cost per pound to LEO are nonsense, they amortise all
of NASA's (space) operations to orbit delivery when a lot of the
R&D is going to take place independent of missions actually flown,
as NASA is not a company it is not required in a strict sense to
charge those costs to operations. Further, as a government agency
I claim NASA revenue is not limited to $ charged upfront for delivery,
if by enabling some commercial activity which generates increased
revenue downstream to government which would not have otherwise
existed this should count towards NASA income at some level.
In practise it is, for example, impossible to ascertain what fraction
of say CNN advertising revenue and taxes generated thereby are due
to 1960's development of launchers and comm satellites and NASA's contribution.
Further, NASA also alleviates potential expenses, for example
at 1-2 million dollars per life, alleviating potential deaths
from a single hurricane justifies a significant fraction of NASA's
annual budget - even if net.libertarians claim that "the free market
could have done it cheaper" (I suspect it could not have provided
weather satellites _at_all_) NASA can still claim some credit for
whatever costs it did alleviate at the price paid.

 ...

   >This is pure nonsense. NASA is not a group of trading companies,
   >and its purpose is to find out how to carry out certain objectives,
   >if possible, given this years budget. They can't borrow upfront costs
   >and they are not free to buy from arbitary suppliers, a significant
   >part of their mission has been to find out how to carry out certain
   >objectives in space and to maintain a group of people who have the
   >experience of carrying out those activities.

   Yes, but if there are other paths to those activities that were not
   chosen for political reasons or for funding reasons, that would have
   been cheaper in the long run, you MUST acknowledge that the US taxpayer
   is getting less for his space dollars than he could BECAUSE OF THE POLITICAL
   SYSTEM HE HAS CHOSEN.  On a purely technical level, the alternative methods
   are often blindingly obvious and easy, but our governmental structure
   won't allow itself to save money all the time.

Yeah, I agree the political system is badly screwed, particularly
when it comes to long term sustained efforts like the space program
seems to require. However, it is also surprisingly good at it and I'm
far from convinced that the free marketers have a better solution.
I don't know what the solution is, I agree something must change
but I haven't seen anyone propose a workable solution, not even if
we were starting ab initio, never mind one that has to account
for pre-existing political reality...

   >Allen is wrong because he treats NASA as if it were a small business
   >operating in a free market, and it isn't. It is not at all clear to
   >me that it should be either.

   That's a flaw of Allen's posts, agreed.  He's pointing out idealized
   technical solutions in what currently is a massively muddled technical,
   political, social, economic, and media problem.  There is nothing wrong
   with doing this: a reasonable goal for a space program might be to
   change its external environment so that it can operate more reasonably
   at the technical level that it should be most concerned with.
   Deciding to do so is a necessary prerequisite for implimenting
   teh "quick technical fixes" that come up so often here, and is rarely
   discussed because it's so massive a problem that it often can't be
   solved except by top-down fiat, rare in this age.

Yup, sometimes you just have to muddle along and do the best you
can...

Maybe this should head for t.p.s now?

|  Steinn Sigurdsson    |I saw two shooting stars last night        |
|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

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

End of Space Digest Volume 16 : Issue 252
------------------------------