Astronut Documentation
----------------------

AstroNUT V1.1
by Kevin Jessup
16-May-1991

Version 1.1
-----------
This version adds a bit of audio and corrects a minor bug:
flag -19, the COMPLEX MODE flag, is now cleared to insure
that 2-d vectors are produced when required.  Also, all
temporary global variables are cleared from the directory
at the end of play.  (Please allow time for cleanup when
the game ends: wait for the HP48SX busy indicator to shut
off.)  Otherwise, the game is the same.

Introduction
------------
AstroNUT is a lunar lander simulation for the 48SX.
It supports 2-d travel (up, down, left, right) and a
random terraine that is generated for each new game.
All routines are in RPL so the screen updates are somewhat
slow.  I still find play acceptable however.

The object of the game is to land on a more or less flat
portion of the lunar surface with a horizontal velocity of
zero and a vertical velocity of less than 5 feet per second.
(Somewhat fast! Change it if you like.)  You have a limited
amount of fuel available to do this.

Initial parameters
------------------
Altitude:            170 feet

Vertical velocity:   -20 feet per second.  A "second" is
                     not the usual unit of time that you
                     are familiar with but how long it takes
                     this game to execute it's main loop!
                     You will have to hit the thrust key
                     quite often to slow down.  Read on...

Horizontal velocity: 5 feet per second.  The direction
                     (left or right) is random.  The initial
                     horizontal position is also random.

Fuel:                100 units.  In gallons, liters, cubic
                     light-years or whatever you'd like to
                     call it :-)

Control keys
------------
8: Apply upward thrust (One push equals thrust of 1/2 g)

4: Apply left thrust (Changes horizontal vel. by 1 ft/sec)

6: Apply right thrust (Changes horizontal vel. by 1 ft/sec)

With each screen update, your downward velocity will
increase due to the acceleration of gravity at a rate of
4 ft/s^2.  It will require 2 hits of the vertical thrust
(key 8) to exactly compensate for the acceleration due to
gravity.

Screen positioning
------------------
As you move to the left and right edges of the display, you
will wrap around to the opposite side.  There are "unlimited"
vertical screens.  You will wrap around at the top and bottom.
When you reach the lowest screen, there will be a slight pause
as the lunar surface is drawn.  If you move above the lowest
screen, the surface will be erased.  The current "flight
parameters" are displayed at the top right of the LCD.

Loading
-------
Once you have successfully transferred the directory to your 48,
just hit PLAY to start.

Be patient...after a little practice, you should be able to
land using only 100 units of fuel.  You can modify the amount
of fuel, thrust and acceleration due to gravity if you like.
Study the code below to find out how.  Have fun!

This is "freeware" but if you'd like to send a few bucks, don't
let that stop you!

Kevin Jessup
9118 N 85th
Milwaukee, WI 53224
(414)355-9752
