Troy's Page


I'll organize this later... -Troy


Cassini: To Saturn on a Budget!






Following is the distance (km, AU) traveled by Cassini from launch to TCM1,
the Heliocentric velocity (km/hr), and the light time (seconds).

DATE        Distance    Distance    Velocity wrt    Light Time
            (km)        (AU)        Sun (km/hr)    (sec)

19971015    0           0.0000      88200          0.09
19971016    2287894     0.0153      96228          1.41
19971017    4599748     0.0307      96372          2.64
19971018    6912144     0.0462      96336          3.84
19971019    9223102     0.0617      96264          5.03
19971020    11532067    0.0771      96156          6.22
19971021    13838872    0.0925      96084          7.41
19971022    16143503    0.1079      95976          8.60
19971023    18446014    0.1233      95904          9.78
19971024    20746499    0.1387      95832          10.97
19971025    23045074    0.1540      95724          12.15
19971026    25341869    0.1694      95652          13.34
19971027    27637022    0.1847      95616          14.52
19971028    29930678    0.2001      95544          15.70
19971029    32222985    0.2154      95472          16.88
19971030    34514097    0.2307      95436          18.06
19971031    36804168    0.2460      95400          19.24
19971101    39093355    0.2613      95364          20.42
19971102    41381815    0.2766      95328          21.59
19971103    43669707    0.2919      95328          22.76
19971104    45957191    0.3072      95292          23.93
19971105    48244427    0.3225      95292          25.09
19971106    50531577    0.3378      95292          26.25
19971107    52818802    0.3531      95292          27.41
19971108    55106264    0.3684      95328          28.56
19971109    57394125    0.3837      95328          29.70



      Twas the night before launch, and all through the pad
      Not a box was malfunctioning, not a CAPS to be had.
      The new actuators were pinned to the nozzles with care,
      In hopes of steering Cassini on its course through the air.
      Propellants were loaded, all snug in their tanks
      While the rivets in the skirts had no cracks in their shanks.
      With Charlie the core, and Kermit on top
      We were set for a mission even protesters can't stop!!
      The only thing bothering the launch crew that night
      Were the flu-like symptoms from that damn mosquito bite!
      When up from the ROCC there arose such a clatter
      I jumped on the MET NET to see what was the matter.
      I was told about Wanda, a most hideous beast
      Who had shifted the wind to blow out of the east.
      The toxics screen with its now reddish glow
      Gave the luster of oxidizer to objects below.
      When what to my still bloodshot eyes should appear
      But a vision of the beach, and people drinking beer.
      With a shiny airline knife, guarded closely all night
      I knew Wanda would soon shift and blow left to right.
      More rapid than blowdown the wind shifted west,
      And elated the team who had all given their best.
      Now Air Force, now NASA, now Lockheed and Boeing
      On Alliant, On Aerojet, let's get this launch going!!
      So in the hopes of launching three Titans this fall,
      Now launch away, launch away, launch away all!!
      Then up from SLC 40 and pushing on past max-Q,
      Launched the Cassini spacecraft, and the Huygens probe too.
      And then in a moment, just after the view,
      I heard the rumble and thunder of each SRMU.
      Just as the turbines started spinning around,
      Down the solids came with a bound.
      They were painted all white, each and every square foot,
      And the nozzle spewed residue of ashes and soot.
      The LRE fired, the core now doing its share
      It looked like a candle burning high in the air.
      Its GCU worked fine, its rate gyros spinning
      The mission looked great, the whole team was grinning.
      Everyone at the Cape was yelling "Go Titan Go!"
      And the plume from the exhaust was as white as the snow.
      Looking up to the sky, I gazed with affection
      And saw the clean separation of each fairing section.
      Then the first stage shut down, and the pyros they blew,
      Then the start cartridge fired, and lit up stage two!
      For a hundred sixty seconds, that engine did burn,
      Sending Cassini to go off to Saturn and learn.
      Moments later came Centaur, its LOX seals replaced
      Pushing its payload off into space.
      Two good Centaur burns, then we all held our breaths
      After good S/V sep, we had Mission Success!!
      The lead protester laid his finger up inside of his nose,
      He went home to dream up another conspiracy to expose.
      Then I grinned to myself as the skies started to lighten,
      Cause there's nothing as great as the launch of a Titan!!
      And I heard someone say as it flew out of sight,
      "God speed Cassini, and to all a good night!!"

By Lt Behm, a true steely-eyed missile man


Footnotes:

 -  A CAPS is a problem statement sheet.
 -  The ROCC is the Range Operations Control Center (which looks like the
    NASA flight control center, only smaller)
 -  We had a minor problem early on with rivets that didn't pass x-ray.
 -  The vehicles are always nick-named. (Kermit and Charlie, this time)
 -  Encephalitis warnings are up in Brevard country - transmitted by
    mosquitos.
 - The toxics screen is a computer simulation of wind effects on the residue
    from the solid rocket motors (just a wee bit rich in sulfuric acid and other
    products) and depicts their fall-out concentrations superimposed on a map.
 -  An LRE is a Liquid Rocket Engine
 -  A GCU is a Guidance Control Unit
 - The reference to the LOX (Liquid Oxygen) seals is in memory of the earlier
    Mars probe which may have blown up when its LOX seals didn't remain intact
    during the protracted time in space flight to the planet.  One theory is
    that when the engine was readied for re-start as the vehicle approached
    Mars, oxygen residue which had built up in the line might have ignited.
 - The reference to the knife is a traditional "ceremony".  One explanation of
    the ritual is that,  like "burying the hatchet", all stress and conflict is
    buried in the sands at the beach by throwing the knife into the ground.

   A goodly amount of libation is consumed in order to seal the spell and is
    presumed to ensure good luck during the launch.  Their is also a "guard"
    cadre of personnel not essential to final launch processing who remain with
    the knife until launch - continuing the essential flow of libation so as to
    break the spell.  It works, don't knock it; but launch delays are really
    hard on the guard.


The Cassini Sendoff Song
(sung to the tune of "Tom Dooley")

started on this project
many years ago
congress and the budget
tossed us to and fro

once was CRAF/Cassini
Comet Rendezvous
In nineteen hundred ninety one
money was cut in two

[Chorus:
going back east, Cassini
going back east to fly
going down south, Cassini
time to say good-bye]

Now it's just Cassini
heading into space
Saturn and its satellites
mark the end of the race

Titan and Enceladus
Phoebe and Rhea, too
from trenches to icy caverns
we'll bring forth something new

[Chorus]

Gary, Tom, and Richard
first for K-S-C
turning on their pages
turning in their keys

following soon behind them,
Bill and Jeff and Spe
gonna ride the Titan
gonna make history

[Chorus]



On launch day, we arrived at our cubicles to find a jar of peanuts on the table 
in the Navigation Operations Area with the following note beside them...

The Good Luck Peanuts
Good luck peanuts made their first appearance in 1964 during the Ranger 7
mission.  JPL had had six "failures" prior to this mission - or as we sincerely
believed, "learning experiences."  Rockets had exploded, spacecraft didn't go
where they were supposed to go, and most discouraging of all, Ranger 6 worked
perfectly right up till the point when pictures were supposed to be returned and
then no pictures.  Needless to say when Ranger 7 was ready to launch, everyone
involved was anxious.  There had even been Congressional meetings and reports on
closing JPL down.

Ranger 7 launch day arrived and with it came the peanuts.  I thought they might
take some of the edge off the anxiety in the mission operations room.  The rest
is history.  The Ranger Program was a resounding success with #7, #8, and #9
performing flawlessly, returning the pictures that were later used in the
evolution of the Apollo program.  The peanuts showed up for each launch, and
even showed up on the informal Ranger check lists."

After Ranger there were many other missions - Mariners, Voyagers, Magellan, just
to name a few - all benfiting from the peanut tradition of keeping cool under
fire.  There were times when the peanuts didn't make it to launch, and looking back
we had about a 50-50 chance or less of surviving some catastrophic event when
they weren't there.

On one mission the peanuts were supplied but were lost prior to launch - the
spacecraft exploded a few months later.  On another mission, the peanuts never
made it till my wife mentioned a launch delay reaching nearly 40 days.  We
supplied the traditional peanuts, and a successful launch occurred the next day.

Up until Voyager, the peanuts only showed up at launch.  However, we were happy
to have them with us for the Voyager Titan encounter/occultation in the early
80's.  The encounter was in the evening, and friends invited me to come by about
half an hour before the encounter.  What a mess things were in.  The trackig
sation was in Madrid, Spain, and they were having a terrible rain storm there,
interfering with signal reception.  In addition, there was a Soviet spacecraft
broadcasting on a very close frequency, also interfering.  On top of all this my
friends were convinced they had made a mistake in generating the Titan aiming
point, and we were going to miss the occultation zone.  We had designed that
trajectory for Titan years before, and had given up the possibility of targeting
to Pluto for this Titan encounter.  We passed around the peanuts in a somewhat
dejected mood.  A few minutes later, just in time, the weather cleared in Spain,
and the Soviet spacecraft went off the air.  Of course my friends had calculated
the aiming point with their usual world-class precision, and the encounter was a
huge success.

There are other stories that go along with the peanuts, but you get the idea. 
They're kind of a tradition, now -- a kind of reduce-the-tension joke -- for
people working on the edge of technology application.  Superstition? I hope not
-- not in this bastion of logic and reason!

D. Wallace, JPL



     ___    _____     ___                                               
    /_ /|  /____/ \  /_ /|       Horizons On-line Ephemeris System v2.51
    | | | |  __ \ /| | | |       Solar System Dynamics Group            
 ___| | | | |__) |/  | | |__     Jet Propulsion Laboratory              
/___| | | |  ___/    | |/__ /|   Pasadena, CA, USA                      
|_____|/  |_|/       |_____|/                                           


Date:    11/5/97  3:44 PM

   Cassini SPK file 971103_SCEPH_LP0_SP0.SPK has been made available on 
the Horizons ephemeris system.

   The system allows people to connect and access the file to derive
various quantities without having to program or obtain the SPK file
themselves. So far, 10870 connections have generated 18210 ephemeris
products in the last year for asteroids, comets, planets and natural
satellites.  Cassini is the first s/c trajectory made available this way.

   If you wish to access the system, I recommend starting with the
telnet access. The same program can also be accessed by WWW browser or
by mailing a namelist command file to the program, but the interactive
telnet system offers all functions and is a good place to start.

How to Access:
==============

   From UNIX or most Mac telnet programs (like NCSA telnet), just type
"telnet ssd.jpl.nasa.gov 6775". The program will start. No ID or password
is needed. 6775 is the port number.

   A prompt will be displayed. Type '?' or '?!' for brief or full
explanations respectively, at any prompt.

   Type "cassini" (case-insensitive). A data screen will be displayed.
I hope to expand this for Cassini, as shown in the example attached.
If you have any comments or data, let me know.

   You can mail, ftp or Kermit the data screen to yourself. For now,
type 'e' for ephemeris. You can make 3 types of custom ASCII tables:

       1) Observer tables (topo or geocentric).
            ~50 quantities are selectable: RA/DEC, AZ/EL, etc.
       2) Vectors (Cassini wrt to any planet or satellite or Sun)
       3) Osculating elements (Cassini wrt other objects)

   Just answer the prompts to develop the type of table you want.
? or ?! at any prompt explains that prompt. When you are done,
the table will be displayed and you can e-mail, ftp or kermit it
back to your local machine.

   Type 'q' at any prompt to quit.
=============

Let me know if there are any questions or concerns re: the system.
I will post a news bulletin on the system announcing the Cassini
trajectory availability late tomorrow, unless I hear otherwise.