SCENARIO:  You are the pilot of a small space vehicle in orbit,
along  with  your Mother Ship, around a large black hole in space.
Your  vechicle  is supplied with oxygen for life support, fuel for
maneuvering,  and  torpedoes for destruction of asteroids captured
by  the  gravitational force of the black hole.  The object of the
game is simply to survive in orbit as long as possible.  To refill
your   supplies   of   oxygen,   fuel,  and  torpedoes,  you  must
successfully  rendezvous  and  dock  with  the  Mother  Ship.   To
preserve  these  vital  supplies, you must protect the Mother Ship
from destruction.
                                                                           
   MODES OF PLAY:  The game can be played as a 3D projection, "Run
3D",  or  as a red-blue dual image projection requiring the use of
red-blue  3D glasses, "Run Dual 3D".  Three modes of operation are
provided called "Learn", "Play", and "Demo".

   In  the  Learn  mode,  you  have  unlimited  oxygen,  fuel, and
torpedoes,  and  neither you nor the Mother Ship can be destroyed.
The Learn mode allows you to practice maneuvering in orbit without
being immediately destroyed.
                                                                           
   In  the  Play mode, oxygen, fuel, and torpedoes are consumed as
they  are  used  and must be resupplied by docking with the Mother
Ship.   Quantities  of  these  supplies remaining on your ship are
indicated  on  the  screen, and an alarm will sound if supplies of
oxygen  or  fuel are nearly gone.  Also indicated on the screen is
elapsed  time  in seconds.  Survival time in excess of 300 seconds
is an excellent score.

   The  Demo  mode is a replay of an encounter with a famous pilot
at  the  controls  to  prove  that it is possible to survive for a
short  while, at least.  A small symbol at screen lower left shows
the  position  of  the  joystick  at  all times to demonstrate the
technique of maneuvering in orbit.
                                                                           
   CONTROLS:   Your  vehicle  thrusters  are  controlled using the
joystick   (connector   #2).    Your  vehicle  is  accelerated  in
directions  parallel  or  diagonal  to  playfield  grid  lines  by
joystick   movement.    Torpedoes   are  launched  in  these  same
directions  by joystick movement with the "Fire" button down.  You
are limited to two torpedoes at a time.

   In  case  of exhaustion, you can cause the game to pause at any
time by pressing the spacebar.
                                                                           
   DOCKING:   You  can dock with the Mother Ship by making contact
while  matching your speed and direction of motion.  If docking is
perfect, you vehicle will be taken aboard the Mother Ship.  If you
make  hard  contact,  you will hear the clang of your hull against
the  Mother  Ship,  but docking will be successful.  If your speed
and  direction  do not match within acceptable limits, you will be
destroyed.  Once docked, undocking is accomplished by pressing the
Fire button.  In any event, you cannot remain docked for more than
10 seconds.
                                                                           
   ORBITAL  MOTION:   Although you have powerful thrusters, you do
not have enough fuel to constantly overcome the gravitational pull
of  the black hole.  In order to survive, then, you must achieve a
stable  orbit  allowing  you  to  cease  expenditure of fuel while
launching  torpedoes  to  protect the Mother Ship.  Expenditure of
fuel  should only be required to change the shape of your orbit to
rendezvous  with  the  Mother  Ship, or to move quickly out of the
path of an approaching asteroid.
                                                                           
   Changing  the  shape  of  your  orbit in a predictable way will
require  some  practice.   The  key to these maneuvers is to avoid
moving  either  directly  toward  or  directly away from the black
hole.   Instead,  move your vehicle around the black hole, and let
its gravity pull your vehicle into an orbit.

   Begin in the Learn mode, and observe the motion of your vehicle
without applying any thrust.  Generally, you will find yourself in
an oblong or elliptical orbit which swings very close to the black
hole  at  one  end,  and  far  out  into  space  at the other end.
Experiment  with  applying  thrust  in  short bursts either in the
direction  you  are  moving  (acceleration)  or  opposite  to  the
direction  you  are moving (deceleration).  To achieve predictable
results,  it  is  best not to apply thrust in other than these two
directions.   In  general,  thrust in the direction of motion will
take  you  into a higher orbit while thrust opposite the direction
of motion will take you into a lower orbit.
                                                                           
   The  ability  to  change your orbit from elliptical to circular
shape   will   be   useful   in  docking  with  the  Mother  Ship.
Deceleration  at  the  closest point of approach to the black hole
will  circularize  your  orbit  at a small distance from the black
hole.   Acceleration  at  the  farthest  point in the path of your
orbit will result in a circular orbit at a large distance from the
black hole.

   Observe  the  joystick position while running the Demo mode for
an  illustration  of  the  techniques  required to control orbital
motion.
                                                                           
   CREDITS:   ORBIT 3D was written by Richard Horne for use in the
public domain.  The game was written entirely in assembly language
using the Metacomco assembler and the Metascope debugger.  Sprites
were  edited  using  Sprite  Editor  by  Scott  Lamb.  Sounds were
digitized   using   the  Perfect  Sound  digitizer  and  software.
Inspiration  for  the  Dual  3D  mode  comes from the excellent 3D
Breakout by Tim Kemp.

   Finally,  much  credit  goes  to Rama Horne, who tolerated with
good  humor  the  hundreds  of  hours necessary for her husband to
write and debug this program.