xlong is satellite longitude measured easterly in radians
if(nonce.gt.0) go to 311
nonce =1
if(fract.gt.1.0E-9_10) go to 311
xlong=atan2(cslng(1),cclng(1))       /   1.7453292519943296E-2_10
write(6,305)   jd,fract,xlong
305 format(i8,1p, 2d22.14)
311 continue

ncall=-2 setup once per iteration of a given step for partials
ncall=-1 setup once per iteration of a given step for motion
ncall= 0 setup once per step
ncall= k evaluate acceleration for equation k.gt.0

for les-8 and les-9 earth satellites in subroutine lesthp
con1(1) = weight of satellite in pounds (if zero, default launch
values used in in computing radiation pressure and
thrust accelerations)
con(17) = solvable parameter multiplying les-8/9 thrust
(if zero, assumed one)
con(18) = solvable parameter multiplying les-8/9 radiation
pressure (if zero, assumed one)

jthrst = 0 no thrust at start, thrust at end of thrust  interval
as these points are approached during integration
jthrst = 1 vice-versa during starting proceedure for thrust
initiation and termination

determine if satellite in shadow (lambda in /sbthng/)
sunlight  lambda=1
penumbra  lambda between 0 and 1
umbra     lambda=0

calculate sun azimuth and elevation in satellite frame
azimuth measured from yaw axis positive to roll
elevation is angle above yaw-roll plane
bcor = coordinates of satellite relative to sun

calculate solar radiation pressure force on les-8/9
radfor(1) = force in x direction (z2 roll)   (micropounds)
radfor(2) = force in y direction (z3 yaw)    (micropounds)
radfor(3) = force in z direction (z1 pitch)  (micropounds)

itherf = 0 no thrust or attitude output from subroutine lestin
itherf = 1 there is the following thrust and attitude output
thrst  = signed thrust in postive roll direction (micropounds)
if thrust positive, thrusters on -z2 roll face are firing
with dv in +z2 roll direction
(west face on les9, dv with orbital velocity)
(east face on les8, dv against orbital velocity)
if thrust negative, thrusters on +z2 roll face are firing
with dv in -z2 roll direction
(east face on les9, dv against orbital velocity)
(west face on les8, dv with orbital velocity)
note: les8 is turned upside down from les9
er1pt  = attitude error about z1 pitch axis (radians)
er2rl  = attitude error about z2 roll axis (radians)
er3yw  = attitude error about z3 yaw axis (radians)
of1pt  = offset angle about z1 pitch axis (radians)
(between -180 and +180 deg)
of2rl  = offset angle about z2 roll axis (radians)
(between -11.25 and +11.25 deg)