Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_2/V15NO270.TXT

Internet Message Format | 1993-07-13 | 41KB

Date: Thu,  1 Oct 92 05:27:33
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #270
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu,  1 Oct 92       Volume 15 : Issue 270

Today's Topics:
       Diffs to sci.space/sci.astro Frequently Asked Questions
                 Mariner Mark II vs smaller missions
                    Space FAQ 01/15 - Introduction
              Space FAQ 06/15 - Constants and Equations
               Space FAQ 07/15 - Astronomical Mnemonics
                     Space FAQ 08/15 - Addresses
       Space FAQ 15/15 - Orbital and Planetary Launch Services

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 30 Sep 92 23:04:09 GMT
From: Jon Leech <[e-mail]>
Subject: Diffs to sci.space/sci.astro Frequently Asked Questions
Newsgroups: sci.space,sci.astro,news.answers

Archive-name: space/diff

DIFFS SINCE LAST FAQ POSTING (IN POSTING ORDER)

(These are hand-edited context diffs; do not attempt to use them to patch
old copies of the FAQ).

===================================================================
diff -t -c -r1.12 FAQ.constants
*** /tmp/,RCSt1a23513    Wed Sep 30 19:02:51 1992
--- FAQ.constants    Wed Sep 30 18:59:04 1992
***************
*** 48,94 ****

          a = 4 pi**2 r / t^2

!      For circular Keplerian orbits, where u is gravitational constant, a is
!          semimajor axis of orbit, P is period.
!          v^2 = u/a
!          P   = 2pi/(Sqrt(u/a^3))
!          u   = G * M (can be measured much more accurately than G or M)
!
!          Vc = sqrt(M * G / r)
!          Vesc = sqrt(2 * M * G / r) = sqrt(2) * Vc
!          The period of an eccentric orbit is the same as the period of a
!         circular orbit with the same semi-major axis
!          1/2 V**2 - G * M / r = K    (conservation of energy)
!              where
!          Vc   = velocity of a circular orbit (you have something like this)
          Vesc = escape velocity
          K    = -G * M / 2 / a
!          M    = Mass of orbited object
!          G    = Gravitational constant
          r    = radius of orbit (measured from center of mass of system)
          V    = orbital velocity

      Change in velocity required for a plane change of angle phi in a
      circular orbit:

          delta V = 2 sqrt(GM/r) sin (phi/2)

!      Energy to put mass m into a circular orbit (ignoring rotational
!      velocity of the Earth, which reduces the energy a bit).

          GMm (1/Re - 1/2Rcirc)
          Re = radius of the earth
          Rcirc = radius of the circular orbit.

!      Classical rocket equation (dv = change in velocity, ve = exhaust
!        velocity, x = reaction mass, m1 = rocket mass excluding reaction
!        mass):
!
!          dv = Ve * ln((m1 + x) / m1)
!         = Ve * ln((final mass) / (initial mass))
!          Ve = Isp * g = exhaust velocity, m / s
          Isp = specific impulse of engine
!          g = 9.80665 m / s^2

      Relativistic rocket equation (constant acceleration)

--- 48,97 ----

          a = 4 pi**2 r / t^2

!      For circular Keplerian orbits where:
!          Vc   = velocity of a circular orbit
          Vesc = escape velocity
          K    = -G * M / 2 / a
!          M    = Total mass of orbiting and orbited bodies
!          G    = Gravitational constant (defined below)
!          u    = G * M (can be measured much more accurately than G or M)
          r    = radius of orbit (measured from center of mass of system)
          V    = orbital velocity
+          P    = orbital period
+          a    = semimajor axis of orbit

+          Vc   = sqrt(M * G / r)
+          Vesc = sqrt(2 * M * G / r) = sqrt(2) * Vc
+          V^2  = u/a
+          P    = 2 pi/(Sqrt(u/a^3))
+          K    = 1/2 V**2 - G * M / r (conservation of energy)
+
+          The period of an eccentric orbit is the same as the period
+         of a circular orbit with the same semi-major axis.
+
      Change in velocity required for a plane change of angle phi in a
      circular orbit:

          delta V = 2 sqrt(GM/r) sin (phi/2)

!      Energy to put mass m into a circular orbit (ignores rotational
!      velocity, which reduces the energy a bit).

          GMm (1/Re - 1/2Rcirc)
          Re = radius of the earth
          Rcirc = radius of the circular orbit.

!      Classical rocket equation, where
!          dv  = change in velocity
          Isp = specific impulse of engine
!          Ve  = exhaust velocity
!          x   = reaction mass
!          m1  = rocket mass excluding reaction mass
!          g   = 9.80665 m / s^2
!
!          Ve  = Isp * g
!          dv  = Ve * ln((m1 + x) / m1)
!          = Ve * ln((final mass) / (initial mass))

      Relativistic rocket equation (constant acceleration)

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

Date: 30 Sep 92 23:56:50 GMT
From: Anita Cochran <[e-mail]>
Subject: Mariner Mark II vs smaller missions
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Mike Wexler) writes:
> [e-mail] (Anita Cochran) writes:
>
> It goes with out saying that A single-purpose craft won't be able to
> study the systematics as well as a more expensive multipurpose craft.
> I think the more important question is whether several simple, quick &
> dirty craft are more cost effective than a single expensive craft.
>
> >Well, if we agree that we want to study the system as a whole, this
> >puts certain requirements on the instrument complement.  It suggests
> >one needs an imaging instrument, IR and UV spectrometers, and
> >fields and particle experiments.  A probe for Titan's atmosphere
> >is a nice thing to have too, once you have a spacecraft going that
> >way.  So, add these together and what do you have?  You have
> >a Mariner Mark II class mission.  And once the spacecraft is going,
> >you might as well send a full spacecraft.
>
> Imagine instead of a Mariner Mark II class mission you have a series of
> missions starting with a relay satellite and following up with separate
> craft with imagine, IR, UV and fields and particle instruments. And with
> the quick turn around you can send updated instruments based on knowledge
> gained by early instruments. You can afford to try more risky techniques
> like ion propulsion and aerobraking.
>


This still does not allow for the systematic studies.  Systematic studies
require that you study the various components at the same time.  We know
that Saturn is temporally variable -- look at the Saturnian storms
this last year.  And it is not sufficient to study part of the problem
without the other problems.  If you put the fields and particles experiments
in orbit, you really should have the UV spectrometer since much of
the fields phenomena like aurorae and sub-storms have a UV signature.
And you really would like an image to put the conditions in the atmosphere
in context.  So now you are talking UVS, imaging and fields and particles.
That is NOT a small mission any more.  Now, you say we will study the

surfaces so we would like to do some spectral work so we send VIMS
(visual and Infrared Mapping Spectrometer) and maybe cover the thermal
IR.  But we would like to have things in context and want to study
the geomorphology  so you have to send
a camera.  This is also NOT a small mission.  Now you want to study the
atmosphere.  Well, you need the UV spectrometer and probably CIRS (Cassini
IR spectrometer) and, guess what, you need imaging to put things in context
and to study the dynamics.  None of these are small missions.
And by the time you have now sent 3 moderate missions  and they should
all go at the same time (see the temporal issue above) you are back to
a big mission so let's fly Cassini.

Now, if you  don't want systematics, the smaller missions are fine but if
you concede that you want to study the systematics, you  have
to have a big mission.

And new technology does not only mean ion drives and solar sails.  The
CIRS is THE MOST SOPHISTICATED IR spectrometer we have yet built for
space.  Its PI expressed the opinion last week at a Goddard meeting that
it probably is the most sophisticated which will ever fly since you cannot
do it smaller (this has nothing to do with detectors or electronics but
the need for big optics).  And the Ion Mass Spectrometers are getting
more and more sophisticated.  And the CCDs which were developed for
CRAF and Cassini opened up a whole new world in CCDs and resulted in
the new WF/PC II cameras on HST.  So you see, these missions are cutting
edge in their own way.  Yes, they are expensive.  And there is where
you must make the decision of what are your priorities and what kinds
of questions you want to answer.  There is no absolute path but
Cassini is NOT old-fashioned technology.
--
 Anita Cochran  uucp:  !utastro!anita
                arpa:  [e-mail]
                snail: Astronomy Dept., The Univ. of Texas, Austin, TX, 78712
                at&t:  [phone]

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

Date: 30 Sep 92 23:05:42 GMT
From: Jon Leech <[e-mail]>
Subject: Space FAQ 01/15 - Introduction
Newsgroups: sci.astro,sci.space,news.answers

Archive-name: space/intro
Last-modified: $Date: 92/09/30 18:59:11 $

    FREQUENTLY ASKED QUESTIONS ON SCI.SPACE/SCI.ASTRO

    INTRODUCTION

    This series of linked messages is periodically posted to the Usenet
groups sci.space and sci.astro in an attempt to provide good answers to
frequently asked questions and other reference material which is worth
preserving. If you have corrections or answers to other frequently asked
questions that you would like included in this posting, send email to
[e-mail] (Jon Leech).

    If you don't want to see the FAQ, add 'Frequently Asked Questions' to
your KILL file for this group (if you're not reading this with a newsreader
that can kill articles by subject, you're out of luck).

    The FAQ volume is excessive right now and will hopefully be trimmed down
by rewriting and condensing over time. The FAQ postings are available in
the Ames SPACE archive in FAQ/faq<#>.

    Good summaries will be accepted in place of the answers given here. The
point of this is to circulate existing information, and avoid rehashing old
answers. Better to build on top than start again. Nothing more depressing
than rehashing old topics for the 100th time. References are provided
because they give more complete information than any short generalization.

    Questions fall into three basic types:

    1) Where do I find some information about space?

    Try your local public library first. The net is not a good place to ask
    for general information. Ask INDIVIDUALS (by email) if you must. There
    are other sources, use them, too. The net is a place for open ended
    discussion.

    2) I have an idea which would improve space flight?

    Hope you aren't surprised, but 9,999 out of 10,000 have usually been
    thought of before. Again, contact a direct individual source for
    evaluation. NASA fields thousands of these each day.

    3) Miscellanous queries.

    These are addressed on a case-by-case basis in the following series of
    FAQ postings.


    SUGGESTIONS FOR BETTER NETIQUETTE

    Read news.announce.newusers if you're on Usenet.
    Minimize cross references, [Do you REALLY NEED to?]
    Edit "Subject:" lines, especially if you're taking a tangent.
    Send mail instead, avoid posting follow ups. (1 mail message worth
    100 posts).
    Internet mail readers: send requests to add/drop to SPACE-REQUEST
    not SPACE.
    Read all available articles before posting a follow-up. (Check all
    references.)
    Cut down attributed articles (leave only the points you're
    responding to; remove signatures and headers). Summarize!
    Put a return address in the body (signature) of your message (mail
    or article), state your institution, etc. Don't assume the
    'reply' function of mailers will work.
    Use absolute dates. Post in a timely way. Don't post what everyone
    will get on TV anyway.
    Some editors and window systems do character count line wrapping:
    keep lines under 80 characters for those using ASCII terminals
    (use carriage returns).


    INDEX TO LINKED POSTINGS

    I've attempted to break the postings up into related areas. There isn't
    a keyword index yet; the following lists the major subject areas in each
    posting. Only those containing astronomy-related material are posted to
    sci.astro (indicated by '*' following the posting number).

    #    Contents

    1*    Introduction
        Suggestions for better netiquette
        Index to linked postings
        Notes on addresses, phone numbers, etc.
        Contributors

    2*    Network resources
        Overview
        Mailing lists
        Periodically updated information
        Warning about non-public networks

    3*    Online (and some offline) sources of images, data, etc.
        Introduction
        Viewing Images
        Online Archives
        NASA Ames
        NASA Spacelink
        National Space Science Data Center
        Space And Planetary Image Facility
        Space Telescope Science Institute Electronic Info. Service
        Astronomical Databases
        Astronomy Programs
        Orbital Element Sets
        SPACE Digest
        Landsat & NASA Photos
        Planetary Maps
        Cometary Orbits

    4*    Performing calculations and interpreting data formats
        Computing spacecraft orbits and trajectories
        Computing planetary positions
        Computing crater diameters from Earth-impacting asteroids
        Map projections and spherical trignometry
        Performing N-body simulations efficiently
        Interpreting the FITS image format
        Sky (Unix ephemeris program)
        Three-dimensional star/galaxy coordinates

    5*    References on specific areas
        Publishers of space/astronomy material
        Careers in the space industry
        DC-X single-stage to orbit (SSTO) program
        LLNL "great exploration"
        Lunar science and activities
        Spacecraft models
        Rocket propulsion
        Spacecraft design
        Esoteric propulsion schemes (solar sails, lasers, fusion...)
        Spy satellites
        Space shuttle computer systems
        SETI computation (signal processing)
        Amateur satellies & weather satellites
        Tides

    6*    Constants and equations for calculations

    7*    Astronomical Mnemonics

    8    Contacting NASA, ESA, and other space agencies/companies
        NASA Centers / Arianespace / ESA / NASDA / Soyuzkarta / Space
        Camp / Space Commerce Corporation / Spacehab / SPOT Image
        Other commercial space businesses

    9    Space shuttle answers, launch schedules, TV coverage
        Shuttle launchings and landings; schedules and how to see them
        How to receive the NASA TV channel, NASA SELECT
        Dial-A-Shuttle and how to use it
        Amateur radio frequencies for shuttle missions
        Solid Rocket Booster fuel composition

    10    Planetary probes - Historical Missions
        US planetary missions
        Mariner (Venus, Mars, & Mercury flybys and orbiters)
        Pioneer (Moon, Sun, Venus, Jupiter, and Saturn flybys and orbiters)
        Ranger (Lunar lander and impact missions)
        Lunar Orbiter (Lunar surface photography)
        Surveyor (Lunar soft landers)
        Viking (Mars orbiters and landers)
        Voyager (Outer planet flybys)
        Soviet planetary missions
        Soviet Lunar probes
        Soviet Venus probes
        Soviet Mars probes
        Japanese planetary missions
        Planetary mission references

    11    Upcoming planetary probes - missions and schedules
        Galileo
        Mars Observer
        CRAF
        Cassini
        Other space science missions

    12    Controversial questions
        What happened to the Saturn V plans
        Why data from space missions isn't immediately available
        Risks of nuclear (RTG) power sources for space probes
        Impact of the space shuttle on the ozone layer
        How long can a human live unprotected in space
        Using the shuttle beyond Low Earth Orbit
        The "Face on Mars"

    13    Space activist/interest/research groups and space publications
        Groups
        Publications
        Undocumented Groups

    14    How to become an astronaut

    15    Orbital and Planetary Launch Services


    NOTES ON ADDRESSES, PHONE NUMBERS, ETC.

    Unless otherwise specified, telephone numbers, addresses, and so on are
    for the United States of America. Non-US readers should remember to add
    the country code for telephone calls, etc.


    CREDITS

    Eugene Miya started a series of linked FAQ postings some years ago which
    inspired (and was largely absorbed into) this set.

    Peter Yee and Ron Baalke have and continue to spend a lot of their own
    time setting up the SPACE archives at NASA Ames and forwarding official
    NASA announcements.

    Many other people have contributed material to this list in the form of
    old postings to sci.space and sci.astro which I've edited. Please let me
    know if corrections need to be made. Contributors I've managed to keep
    track of are:

    [e-mail] (Francis Reddy)    - map projections
    [e-mail] (Richard Akerman)   - crater diameters
    [e-mail] (Lisa Weigel)    - SEDS info
    [e-mail] (Srinivas Bettadpur) - tides
    [e-mail] (Alan Wm Paeth) - map projections
    [e-mail] (Allen W. Sherzer)        - Great Exploration
    [e-mail] (Ron Baalke)    - planetary probe schedules
    [e-mail] (Timothy Banks)    - map projections,
    variable star analysis archive
    [e-mail] (Bernie Rosen)    - Space Camp
    [e-mail] (Barry Schlesinger)   - FITS format
    [e-mail] (Craig E. Ward)        - space group contact info
    [e-mail] (Tom Chapin)        - planetary positions
    [e-mail] (D. Alan Cunningham)    - NASA Spacelink
    [e-mail] (Cliff Yamamoto) - orbital elements
    [e-mail] (Anthony Datri)        - PDS/VICAR viewing software
    [e-mail] (Dave Rickel)        - orbit formulae
    [e-mail] (Phil Fraering)        - propulsion
    [e-mail] (Dani Eder)        - Saturn V plans, SRBs
    [e-mail] (Eugene N. Miya)    - introduction,
    NASA contact info, started FAQ postings
    [e-mail] (Gary Morris)        - amateur radio info
    [e-mail] (Terry Gaetz)        - N-body calculations,
    orbital dynamics
    [e-mail] (Steve Grandi)        - planetary positions
    [e-mail] (Dale M. Greer)   - constants
    [e-mail] (Henry Spencer)    - survival in vacuum,
    astronaut how-to, publication refs, DC-X
    [e-mail] (William Higgins)    - RTGs, publishers,
    shuttle landings, spysats, propulsion, "Face on Mars"
    [e-mail] (Hal Mueller)    - map projections,
    orbital dynamics
    [e-mail] (Jim Bowery)        - propulsion, launch services
    [e-mail] (Jim Scotti)    - planetary positions
    [e-mail] (Kieran A. Carroll)- refs for spacecraft design
    [e-mail] (Kenneth Ng)        - RTGs
    [e-mail] (Larry Klaes)    - planetary probe history
    [e-mail] (Jon Leech)        - crater diameters
    [e-mail] (Lou Adornato)        - orbital dynamics
    [e-mail] (Maury Markowitz)   - propulsion
    [e-mail]        - N-body calculations
    [e-mail] (Marc Wayne Mcconley)    - space careers
    [e-mail] (Mark Brader)            - Mariner 1 info.
    [e-mail] (Mark Maimone)            - SPACE Digest
    [e-mail] (Dr. Nick Watkins)    - models, spysats
    [e-mail] (Colby Kraybill)    - SPIF data archive
    [e-mail] (Kenneth W Durham)    - cometary orbits, IAU
    [e-mail] (Paul Blase)    - propulsion
    [e-mail] (Peter Scott)    - RTGs
    [e-mail] (Paul W. Schleck)    - AMSAT, ARRL contact info
    [e-mail] (Rodney Brown)        - propulsion refs
    [e-mail] (Ran Atkinson)    - FTPable astro. programs
    [e-mail] (R. Michael Jungclas)- models
    [e-mail] (David Seal)    - Cassini mission schedule
    [e-mail] (Mary Shafer)    - photos, shuttle landings
    [e-mail] (Willie Smith)    - photos
    [e-mail] (Stephen Dixon)    - shuttle audio frequencies
    [e-mail] (Ray Sterner)    - planetary positions
    [e-mail] (Phil Stooke)    - planetary maps
    [e-mail] (Ted Anderson)    - propulsion
    [e-mail] (Terry Hancock)    - NASA center info
    [e-mail] (Bill Thorson) - FITS info
    [e-mail] (Todd L. Masco)    - SPACE Digest
    [e-mail] (Tom Horsley)    - refs for algorithms
    [e-mail] (Veikko Makela)    - orbital element sets
    [e-mail] (Wayne Hayes)    - constants
    [e-mail] (Matthew P Wiener) - Voyager history
    [e-mail] (Yoshiro Yamada)    - ISAS/NASDA missions
    [e-mail] (Peter Yee)        - AMES archive server,
    propulsion

    In Net memoriam:
    Ted Flinn

NEXT: FAQ #2/15 - Network Resources

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

Date: 30 Sep 92 23:07:01 GMT
From: Jon Leech <[e-mail]>
Subject: Space FAQ 06/15 - Constants and Equations
Newsgroups: sci.astro,sci.space,news.answers

Archive-name: space/constants
Last-modified: $Date: 92/09/30 18:59:02 $

CONSTANTS AND EQUATIONS FOR CALCULATIONS

    This list was originally compiled by Dale Greer. Additions would be
    appreciated.

    Numbers in parentheses are approximations that will serve for most
    blue-skying purposes.

    Unix systems provide the 'units' program, useful in converting
    between different systems (metric/English, etc.)

    NUMBERS

    7726 m/s     (8000)  -- Earth orbital velocity at 300 km altitude
    3075 m/s     (3000)  -- Earth orbital velocity at 35786 km (geosync)
    6378 km         (6400)  -- Mean radius of Earth
    1738 km         (1700)  -- Mean radius of Moon
    5.974e24 kg     (6e24)  -- Mass of Earth
    7.348e22 kg     (7e22)  -- Mass of Moon
    1.989e30 kg     (2e30)  -- Mass of Sun
    3.986e14 m^3/s^2 (4e14)  -- Gravitational constant times mass of Earth
    4.903e12 m^3/s^2 (5e12)  -- Gravitational constant times mass of Moon
    1.327e20 m^3/s^2 (13e19) -- Gravitational constant times mass of Sun
    384401 km     ( 4e5)  -- Mean Earth-Moon distance
    1.496e11 m     (15e10) -- Mean Earth-Sun distance (Astronomical Unit)

    1 megaton (MT) TNT = about 4.2e15 J or the energy equivalent of
    about .05 kg (50 gm) of matter. Ref: J.R Williams, "The Energy Level
    of Things", Air Force Special Weapons Center (ARDC), Kirtland Air
    Force Base, New Mexico, 1963. Also see "The Effects of Nuclear
    Weapons", compiled by S. Glasstone and P.J. Dolan, published by the
    US Department of Defense (obtain from the GPO).

    EQUATIONS

    Where d is distance, v is velocity, a is acceleration, t is time.

    For constant acceleration
        d = d0 + vt + .5at^2
        v = v0 + at
      v^2 = 2ad

    Acceleration on a cylinder (space colony, etc.) of radius r and
        rotation period t:

        a = 4 pi**2 r / t^2

    For circular Keplerian orbits where:
        Vc     = velocity of a circular orbit
        Vesc = escape velocity
        K     = -G * M / 2 / a
        M     = Total mass of orbiting and orbited bodies
        G     = Gravitational constant (defined below)
        u     = G * M (can be measured much more accurately than G or M)
        r     = radius of orbit (measured from center of mass of system)
        V     = orbital velocity
        P     = orbital period
        a     = semimajor axis of orbit

        Vc     = sqrt(M * G / r)
        Vesc = sqrt(2 * M * G / r) = sqrt(2) * Vc
        V^2  = u/a
        P     = 2 pi/(Sqrt(u/a^3))
        K     = 1/2 V**2 - G * M / r (conservation of energy)

        The period of an eccentric orbit is the same as the period
           of a circular orbit with the same semi-major axis.

    Change in velocity required for a plane change of angle phi in a
    circular orbit:

        delta V = 2 sqrt(GM/r) sin (phi/2)

    Energy to put mass m into a circular orbit (ignores rotational
    velocity, which reduces the energy a bit).

        GMm (1/Re - 1/2Rcirc)
        Re = radius of the earth
        Rcirc = radius of the circular orbit.

    Classical rocket equation, where
        dv    = change in velocity
        Isp = specific impulse of engine
        Ve    = exhaust velocity
        x    = reaction mass
        m1    = rocket mass excluding reaction mass
        g    = 9.80665 m / s^2

        Ve    = Isp * g
        dv    = Ve * ln((m1 + x) / m1)
        = Ve * ln((final mass) / (initial mass))

    Relativistic rocket equation (constant acceleration)

        t (unaccelerated) = c/a * sinh(a*t/c)
        d = c**2/a * (cosh(a*t/c) - 1)
        v = c * tanh(a*t/c)

    Relativistic rocket with exhaust velocity Ve and mass ratio MR:

        at/c = Ve/c * ln(MR), or

        t (unaccelerated) = c/a * sinh(Ve/c * ln(MR))
        d = c**2/a * (cosh(Ve/C * ln(MR)) - 1)
        v = c * tanh(Ve/C * ln(MR))

    Converting from parallax to distance:

        d (in parsecs) = 1 / p (in arc seconds)
        d (in astronomical units) = 206265 / p

    Miscellaneous
        f=ma    -- Force is mass times acceleration
        w=fd    -- Work (energy) is force times distance

    Atmospheric density varies as exp(-mgz/kT) where z is altitude, m is
    molecular weight in kg of air, g is local acceleration of gravity, T
    is temperature, k is Bolztmann's constant. On Earth up to 100 km,

        d = d0*exp(-z*1.42e-4)

    where d is density, d0 is density at 0km, is approximately true, so

        d@12km (40000 ft) = d0*.18
        d@9 km (30000 ft) = d0*.27
        d@6 km (20000 ft) = d0*.43
        d@3 km (10000 ft) = d0*.65


    Titius-Bode Law for approximating planetary distances:

        R(n) = 0.4 + 0.3 * 2^N Astronomical Units (N = -infinity for
        Mercury, 0 for Venus, 1 for Earth, etc.)

        This fits fairly well except for Neptune.

    CONSTANTS

    6.62618e-34 J-s  (7e-34) -- Planck's Constant "h"
    1.054589e-34 J-s (1e-34) -- Planck's Constant / (2 * PI), "h bar"
    1.3807e-23 J/K    (1.4e-23) - Boltzmann's Constant "k"
    5.6697e-8 W/m^2/K (6e-8) -- Stephan-Boltzmann Constant "sigma"
    6.673e-11 N m^2/kg^2 (7e-11) -- Newton's Gravitational Constant "G"
    0.0029 m K     (3e-3)  -- Wien's Constant "sigma(W)"
    3.827e26 W     (4e26)  -- Luminosity of Sun
    1370 W / m^2     (1400)  -- Solar Constant (intensity at 1 AU)
    6.96e8 m     (7e8)     -- radius of Sun
    1738 km         (2e3)     -- radius of Moon
    299792458 m/s      (3e8)  -- speed of light in vacuum "c"
    9.46053e15 m      (1e16) -- light year
    206264.806 AU      (2e5)  -- \
    3.2616 light years (3)     --  --> parsec
    3.0856e16 m     (3e16)  -- /


Black Hole radius (also called Schwarzschild Radius):

    2GM/c^2, where G is Newton's Grav Constant, M is mass of BH,
        c is speed of light

    Things to add (somebody look them up!)
    Basic rocketry numbers & equations
    Aerodynamical stuff
    Energy to put a pound into orbit or accelerate to interstellar
        velocities.
    Non-circular cases?
    Atmosphere scale height for various planets.


NEXT: FAQ #7/15 - Astronomical Mnemonics

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

Date: 30 Sep 92 23:07:06 GMT
From: Jon Leech <[e-mail]>
Subject: Space FAQ 07/15 - Astronomical Mnemonics
Newsgroups: sci.astro,sci.space,news.answers

Archive-name: space/mnemonics
Last-modified: $Date: 92/09/30 18:59:18 $

ASTRONOMICAL MNEMONICS (This is the last FAQ section posted to sci.astro)

    Gathered from various flurries of mnemonic postings on sci.astro.

    Spectral classification sequence: O B A F G K M R N S

    Oh Be A Fine Girl Kiss Me Right Now, Sweetheart. (a classic)

    O'Dell's Big Astronomical Fiasco Gonna Kill Me Right Now Surely
    Obese Balding Astronomy Found Guilty; Killed Many Reluctant
        Nonscience Students.
    Octopus Brains, A Favorite Gastronomical Kitchen Menu,
        Requires No Sauce
    Odd Ball Astronomers Find Generally Kooky Mnemonics
        Really Nifty Stuff
    Oh Big And Ferocious Gorilla, Kill My Roomate Next Saturday
    Oh Boy, A Flash! Godzilla Kills Mothra! Really Not Surprising!
    Oh Boy, An F Grade Kills Me
    On Bad Afternoons Fermented Grapes Keep Mrs. Richard Nixon Smiling
    On, Backward Astronomer, Forget Geocentricity; Kepler's Motions
        Reveal Nature's Simplicity
    Our Bad Astronomy Faculty Gets Killed Monday
    Oven Baked Ants, Fried Gently, Kept Moist, Retain Natural Succulence
    Overseas Broadcast: A Flash!  Godzilla kills Mothra!
        (Rodan Named Successor)
    Overweight Boys and Fat Girls Keep Munching
    Only Bored Astronomers Find Gratification Knowing Mnemonics
    Oh Bloody Astronomy!  F Grades Kill Me

    Order of the planets:

    Sun
    Mercury
    Venus
    Earth (Terra)
    Mars
    (Asteroids)
    Jupiter
    Saturn
    Uranus
    Neptune
    Pluto

    My Very Earnest Mother Just Served Us Nine Pizzas
    Mother Very Thoughtfully Made A Jelly Sandwich Under No Protest
    My Very Erotic Mate Joyfully Satisfies Unusual Needs Passionately
    Men Very Easily Make Jugs Serve Useful Nocturnal Purposes
    Man Very Early Made A Jug Serve Useful Noble Purposes
    My Very Educated Mother Just Showed Us Nine Planets
    My Very Eager Mother Just Showed Us Nine Planets
    My Very Exhausted Mother hAs Just Swept Up a Planetary Nebula
    Most Voters Earn Money Just Showing Up Near Polls
    My Very Educated Mother Just Served Us Nine Pizza-pies
    Many Viscious Elephants Made John, Suzy and Uncle Need Protection
    Solar Mass Very Easily Makes All Jupiter's Satellites Undergo
        Numerous Perturbations.

    Mein Vater erklaert mir jeden Sonntag unseren niedlichen Planeten

    Colors of the spectrum: Red Orange Yellow Green Blue Indigo Violet
    ROY G. BIV  (pronounce as a man's name)
    Richard Of York Gave Battle In Vain
    Read Out Your Good Book In Verse

    Galilean Satellite of Jupiter: Io Europa Ganymede Callisto
    I Expect God Cries
    I Eat Green Cheese

    Ich Erschrecke alle Guten Christen

    Saturnian Satellites
    MET DR THIP
    Miriam's Enchiladas Taste Divine Recently. Tell Her I'm Proud.
    (Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion,
        Iapetus, Phoebe)

    Uranian Satellites:
    MAUTO
    Mispronunciations Afflict Uranus Too Often
    My Angel Uriel Takes Opium
    (Miranda, Ariel, Umbriel, Titania, Oberon)

NOTE: the remaining FAQ sections do not appear in sci.astro, as they cover
    material of relevance only to sci.space.

NEXT: FAQ #8/15 - Contacting NASA, ESA, and other space agencies/companies

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

Date: 30 Sep 92 23:07:10 GMT
From: Jon Leech <[e-mail]>
Subject: Space FAQ 08/15 - Addresses
Newsgroups: sci.space,news.answers

Archive-name: space/addresses
Last-modified: $Date: 92/09/30 18:58:49 $

CONTACTING NASA, ESA, AND OTHER SPACE AGENCIES/COMPANIES

Many space activities center around large Government or International
Bureaucracies.    In the US that means NASA.  If you have basic information
requests: (e.g., general PR info, research grants, data, limited tours, and
ESPECIALLY SUMMER EMPLOYMENT (typically resumes should be ready by Jan.  1),
etc.), consider contacting the nearest NASA Center to answer your questions.

EMail typically will not get you any where, computers are used by
investigators, not PR people. The typical volume of mail per Center is a
multiple of 10,000 letters a day. Seek the Public Information Office at one
of the below, this is their job:

NASA (The National Aeronautics and Space Administration) is the
civilian space agency of of the United States Federal Government.
It reports directly to the White House and is not a Cabinet
post such as the military Department of Defense.  Its 20K+ employees
are civil servants and hence US citizens.  Another 100K+ contractors
also work for NASA.

NASA CENTERS

    NASA Headquarters (NASA HQ)
    Washington DC 20546

    Ask them questions about policy, money, and things of political
    nature. Direct specific questions to the appropriate center.

    NASA Ames Research Center (ARC)
    Moffett Field, CA 94035

    Some aeronautical research, atmosphere reentry, Mars and Venus
    planetary atmospheres. "Lead center" for Helicopter research,
    V/STOL, etc. Runs Pioneer series of space probes.

    NASA Ames Research Center
    Dryden Flight Research Facility [DFRF]
    P. O. Box 273
    Edwards, CA  93523

    Aircraft, mostly. Tested the shuttle orbiter landing
    characteristics. Developed X-1, D-558, X-3, X-4, X-5, XB-70, and of
    course, the X-15.

    NASA Goddard Space Flight Center (GSFC)
    Greenbelt, MD 20771
    [Outside of Washington DC]

    Earth orbiting unmanned satellites and sounding rockets. Developed
    LANDSAT.

    NASA Lewis Research Center (LeRC)
    21000 Brookpark Rd.
    Cleveland, OH 44135

    Aircraft/Rocket propulsion. Space power generation. Materials
    research.

    NASA Johnson Manned Space Center (JSC)
    Houston, TX 77058

    JSC manages Space Shuttle, ground control of manned missions.
    Astronaut training. Manned mission simulators.

    NASA Kennedy Space Flight Center (KSC)
    Titusville, FL 32899

    Space launch center. You know this one.

    NASA Marshall Space Flight Center (MSFC)
    Huntsville, AL 35812

    Development, production, delivery of Solid Rocket Boosters, External
    Tank, Orbiter main engines. Propulsion and launchers.

    NASA Langley Research Center (LaRC)
    Hampton, VA 23665
    [Near Newport News, VA]

    Original NASA site. Specializes in theoretical and experimental
    flight dynamics. Viking. Long Duration Exposure Facility.

    Wallops Flight Center
    Wallops Island, Virginia 23337
        Aeronautical research, sounding rockets, Scout launcher.

    Jet Propulsion Laboratory [JPL/CIT]
    California Institute of Technology
    4800 Oak Grove Dr.
    Pasadena, CA 91109

    The "heavies" in planetary research probes and other unmanned
    projects (they also had a lot to do with IRAS). They run Voyager,
    Magellan, Galileo, and will run Cassini, CRAF, etc. etc.. For
    images, probe navigation, and other info about unmanned exploration,
    this is the place to go.

    JPL is run under contract for NASA by the nearby California
    Institute of Technology, unlike the NASA centers above. This
    distinction is subtle but critical. JPL has different requirements
    for unsolicited research proposals and summer hires. For instance in
    the latter, an SF 171 is useless. Employees are Caltech employees,
    contractors, and for the most part have similar responsibilities.
    They offer an alternative to funding after other NASA Centers.

    Manager, Technology Utilization Office
    NASA Scientific and Technical Information Facility
    Post Office Box 8757
    Baltimore, Maryland 21240

    Specific requests for software must go thru COSMIC at the Univ. of
    Georgia, NASA's contracted software redistribution service. You can
    reach them at [e-mail].

    NOTE: Foreign nationals requesting information must go through their
    Embassies in Washington DC. These are facilities of the US Government
    and are regarded with some degree of economic sensitivity. Centers
    cannot directly return information without high Center approval. Allow
    at least 1 month for clearance. This includes COSMIC.

The US Air Force Space Command can be contacted thru the Pentagon along with
    other Department of Defense offices. They have unacknowledged offices in
    Los Angeles, Sunnyvale, Colorado Springs, and other locations. They have
    a budget which rivals NASA in size.

ARIANESPACE HEADQUARTERS
    Boulevard de l'Europe
    B.P. 177
    91006 Evry Cedex
    France

ARIANESPACE, INC.
    1747 Pennsylvania Avenue, NW Suite 875
    Washington, DC 20006
    (202)-728-9075

EUROPEAN SPACE AGENCY
    955 L'Enfant Plaza S.W.
    Washington, D.C. 20024
    (202)-488-4158

NATIONAL SPACE DEVELOPMENT AGENCY (NASDA)
    4-1 Hamamatsu-Cho, 2 Chome
    Minato-Ku, Tokyo 105, JAPAN

SOYUZKARTA
    45 Vologradsij Pr.
    Moscow 109125
    USSR

SPACE CAMP
    Alabama Space and Rocket Center    U.S. SPACE CAMP
    1 Tranquility Base            6225 Vectorspace Blvd
    Huntsville, AL 35805        Titusville FL  32780
    (205)-837-3400            [phone]

    Registration and mailing list are handled through Huntsville -- both
    camps are described in the same brochure.

    Programs offered at Space Camp are:

    Space Camp - one week, youngsters completing grades 4-6
    Space Academy I - one week, grades 7-9
    Aviation Challenge - one week high school program, grades 9-11
    Space Academy II - 8 days, college accredited, grades 10-12
    Adult Program - 3 days (editorial comment: it's great!)
    Teachers Program - 5 days

SPACE COMMERCE CORPORATION (U.S. agent for Soviet launch services)
    504 Pluto Drive            69th flr, Texas Commerce Tower
    Colorado Springs, CO 80906        Houston, TX 77002
    (719)-578-5490            (713)-227-9000

SPACEHAB
    600 Maryland Avenue, SW
    Suite 201 West
    Washington, DC 20004
    (202)-488-3483

SPOT IMAGE CORPORATION
    1857 Preston White Drive,
    Reston, VA 22091
    (FAX) (703)-648-1813    (703)-620-2200


OTHER COMMERCIAL SPACE BUSINESSES

    Vincent Cate maintains a list with addresses and some info for a variety
of companies in space-related businesses. This is mailed out on the
space-investors list he runs (see the "Network Resources" FAQ) and is also
available by anonymous ftp from furmint.nectar.cs.cmu.edu (128.2.209.111) in
/usr/vac/ftp/space-companies.


NEXT: FAQ #9/15 - Schedules for space missions, and how to see them

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

Date: 30 Sep 92 23:07:48 GMT
From: Jon Leech <[e-mail]>
Subject: Space FAQ 15/15 - Orbital and Planetary Launch Services
Newsgroups: sci.space,news.answers

Archive-name: space/launchers
Last-modified: $Date: 92/09/30 18:59:13 $

ORBITAL AND PLANETARY LAUNCH SERVICES

If anyone has more accurate or more complete information, please post
it and copy [e-mail] (Jim Bowery), who maintains the primary
copy of this item. Don't forget to include the source of the
information.


            PAYLOAD(LBS) DELIVERED TO
COMPANY/VEHICLE $M    LEO    GTO    GEO    ESCAPE    U.STAGE LAUNCHFAIL(1)

MM/Titan4[H]    296    47000    ....    10300    ....    Centaur ....    ....
MM/Titan4    277    49000    15000    5800    ....    IUS    ....    ....
MM/Titan3    160    32500    12474    4100    ....    TOS    ....    ....
AS/Arian44L[H]    110    21164    9259    5500    ....    none    ....    ....
GD/Atlas2    80    15700    6200    3000    ....    Centaur ....    ....
MD/Delta2    52    11100    4010    2000    2816[S] PAMD[H] ....    ....
GW/LongMarch3    45    6614    2866    1433    ....    none    ....    ....
EPAC/EagleS2[E] 30    10000(2)5128    3374    ....(4) USTM(3) 0    0
OSC/Taurus[S]    17    2703    ....    ....    374    ....    0    0
EPAC/EagleS1[E] 15    6000    ....    ....    ....(4) USTM    0    0
AMROC/Aquila[S] 10    2000    1467    ....    ....    none    0    0
SSI/Conestoga    10    1500(5) 900(6)    550(7)    ....        0    0
OSC/Pegasus[H]    9.7    750    ....    ....    ....    none    2    1
EPAC/Eagle[E]    6.7    3000    ....    ....    ....    USTM    0    0

(1) For launches where reflight insurance is issued, the fraction of the
    launch cost indemnified is the failure level for that flight.
    For launches where reflight insurance is not issued, a rough
    estimate is made as to the fraction of the launch cost that
    would have been indemnified.
(2) LEO given is 300nmi altitude [S].
(3) The bipropellant (Isp=323) USTM has a dry weight of approximately 1600LBS
    which must be subtracted from the total weight to determine weight
    available for electronics, power, communication and fuel.  The USTM
    provides station-keeping and course correction in addition to
    transfer and apogee burns.
(4) According to [S] escape requires 170kg MMH/NTO fuel with USTM.
(5) 200nmi altitude 37.9d inclination [S].
(6) 400nmi altitude [S].
(7) Includes Conestoga apogee kick stage weight.


                REFLIGHT
VEHICLE        POLARLBS(9)    INSURANCE(%)    ACCURACY    PAD WEIGHT

MM/Titan4[H]    ....        ....        ....        1910449
MM/Titan4    ....        ....        ....        1885525
MM/Titan3    ....        ....        ....        1492200
AS/Arian44L    ....        ....        ....        1033000
GD/Atlas2    12400        ....        ....        360600
MD/Delta2    8401        ....        ....        450000
GW/LongMarch3    ....        ....        ....        444400
EPAC/EagleS2[E] ....        18        1.4km(9)    268145
OSC/Taurus[S]    2140        ....        ....        ....
EPAC/EagleS1[E] ....        18        1.4km(9)    ....
AMROC/Aquila[S] 1467        ....        ....        ....
SSI/Conestoga    900        ....        9.3km(10)    ....
OSC/Pegasus[S]    649        ....        ....        ....
EPAC/Eagle    ....        18        ....        99134

(9) For unknown data, conservative figures for polar orbit can be
    estimated by dividing LEO weight by 2.
(10) Circular orbit and <0.02d inclination error to 3 sigma [S].
(11) Reduced payload for upper stage with thrust vector control. 1 sigma [S].

Figures given as "...." are to be included in a future release.

Information sources are indicated by a source code within square brackets.
For example [H] means the associated information and subsequent information
comes from the 1989 Hughes Corp. Survey with dollars given in 1989 dollars.

Source codes:    H = 1989 Hughes Corp. Survey
        E = 9/1991 E'Prime Aerospace Corp. report
        S = "A Status Report on the Availability of Expendable
            Launch Vehicles for Small Solar System
            Exploration Payloads", Jim McAdams, Science
            Applications International Corp. 3/31/1991

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

End of Space Digest Volume 15 : Issue 270
------------------------------