Usage of program Asteroid_intercept.pl:

These notes are written with the Linux user in mind. Presumably
the program can be used on any system that has perl and some data
plotting program on it.

This is an early version of the program. I will improve/debug it
in the future.

I wrote these instructions right after working a lot with the program,
so I may be skipping over a few essentials without noticing. If you
need help understanding this, ask me (see email address on the
"contact" web page).

Requirements: Perl interpreter, gnuplot or some other data plotting
program


Asteroid_intercept.pl <task> <date_style> <a> <b> <c> <d> <e> <f> <g> <h> <i> 

where:
<task> = -scan: find a trajectory that goes from earth's position at a
                given departure date to Apophis's position at a given
		arrival date. What needs to be scanned is the orientation
		of the transfer ellipse
         -dv:   find trajectories and delta v for departure and arrival
	        dates within given limits. The "scan" task is done for each
		of them

<date_style>: -date; parameters <a>, <b> are then departure date in
                     notation yyyy/mm/dd
              -epoch; parameters are <a> for departure epoch, <b> for
	              arrival epoch
<a>, <b>:       dates as explained above
<c> - <f>:      additional parameters, see below

example:
./Asteroid_intercept.pl -scan -date 2013/1/26 150
to find a trajectory from earth's position in 2013/1/26 to Apophis's
position 150 days later

example:
./Asteroid_intercept.pl -dv -date 2013/1/1 375 750 750 -no_dv 75 75
                                           ^   ^   ^
                                           |   |   |          ^
					       |
to probe departure dates          2013/1/1 +-  (750/2 days), and
                                           |       | 
                                           |       |------
					   |             |
arrival dates from 2013/1/1 +              (375 days) +- (750/2 days)

output a grid of 75 by 75 points
the last 3 parameters (-no_dv 75 75) are optional, default is 50 by 50
also optional are parameters -allow_multiple_loops <n> to include
trajectories looping multiple times around the sun



Output is in a format suitable for gnuplot with a header stating the
meanings of the data columns
To get started, look at the file "gnucmd" in this directory
Copy the output files E_posn to E_<date> and A_posn to A_<date>
with the appropriate dates as given to the perl program with the
-scan parameter.

Bernhard Adams
31. Aug. 2007