<s>
Systems	B-Application
Tool	I-Application
Kit	I-Application
(	O
formerly	O
Satellite	B-Application
Tool	I-Application
Kit	I-Application
)	O
,	O
often	O
referred	O
to	O
by	O
its	O
initials	O
STK	O
,	O
is	O
a	O
multi-physics	O
software	O
application	O
from	O
Analytical	O
Graphics	O
,	O
Inc	O
.	O
(	O
an	O
Ansys	O
company	O
)	O
that	O
enables	O
engineers	O
and	O
scientists	O
to	O
perform	O
complex	O
analyses	O
of	O
ground	O
,	O
sea	O
,	O
air	O
,	O
and	O
space	O
platforms	O
,	O
and	O
to	O
share	O
results	O
in	O
one	O
integrated	O
environment	O
.	O
</s>
<s>
Originally	O
created	O
to	O
solve	O
problems	O
involving	O
Earth-orbiting	O
satellites	B-Application
,	O
it	O
is	O
now	O
used	O
in	O
the	O
aerospace	O
and	O
defense	O
communities	O
and	O
for	O
many	O
other	O
applications	O
.	O
</s>
<s>
In	O
1989	O
,	O
the	O
three	O
founders	O
of	O
Analytical	O
Graphics	O
,	O
Inc	O
.	O
—	O
Paul	O
Graziani	O
,	O
Scott	O
Reynolds	O
,	O
and	O
Jim	O
Poland	O
,	O
left	O
GE	O
Aerospace	O
to	O
create	O
Satellite	B-Application
Tool	I-Application
Kit	I-Application
(	O
STK	O
)	O
as	O
an	O
alternative	O
to	O
bespoke	O
,	O
project-specific	O
aerospace	O
software	O
.	O
</s>
<s>
The	O
original	O
version	O
of	O
STK	O
ran	O
only	O
on	O
Sun	O
Microsystems	O
computers	O
,	O
but	O
as	O
PCs	O
became	O
more	O
powerful	O
,	O
the	O
code	O
was	O
converted	O
to	O
run	O
on	O
Windows	B-Application
.	O
</s>
<s>
STK	O
was	O
first	O
adopted	O
by	O
the	O
aerospace	O
community	O
for	O
orbit	O
analysis	O
and	O
access	O
calculations	O
(	O
when	O
a	O
satellite	B-Application
can	O
see	O
a	O
ground-station	O
or	O
image	O
target	O
)	O
,	O
but	O
as	O
the	O
software	O
was	O
expanded	O
,	O
more	O
modules	O
were	O
added	O
that	O
included	O
the	O
ability	O
to	O
perform	O
calculations	O
for	O
communications	O
systems	O
,	O
radar	B-Application
,	O
interplanetary	O
missions	O
and	O
orbit	O
collision	O
avoidance	O
.	O
</s>
<s>
As	O
of	O
version	O
12.1	O
(	O
released	O
in	O
2020	O
)	O
,	O
the	O
software	O
underwent	O
a	O
name	O
change	O
from	O
Satellite	B-Application
Tool	I-Application
Kit	I-Application
to	O
Systems	B-Application
Tool	I-Application
Kit	I-Application
to	O
reflect	O
its	O
applicability	O
in	O
land	O
,	O
sea	O
,	O
air	O
,	O
and	O
space	O
systems	O
.	O
</s>
<s>
It	O
was	O
"	O
the	O
first	O
time	O
in	O
three	O
and	O
a	O
half	O
decades	O
that	O
an	O
image	O
 [ had ] 	O
become	O
public	O
that	O
 [ revealed ] 	O
the	O
sophistication	O
of	O
US	O
spy	O
satellites	B-Application
in	O
orbit.	O
"	O
</s>
<s>
Langbroek	O
and	O
astronomer	O
Cees	O
Bassa	O
,	O
identified	O
the	O
specific	O
classified	O
spysat	O
(	O
USA-224	O
,	O
a	O
KH-11	O
satellite	B-Application
with	O
an	O
objective	O
mirror	O
as	O
large	O
as	O
the	O
Hubble	O
Space	O
Telescope	O
)	O
that	O
had	O
taken	O
the	O
photograph	O
,	O
and	O
the	O
time	O
when	O
it	O
was	O
taken	O
on	O
a	O
particular	O
satellite	B-Application
pass	O
.	O
</s>
<s>
The	O
STK	O
interface	O
is	O
a	O
standard	O
GUI	O
display	O
with	O
customizable	O
toolbars	O
and	O
dockable	O
maps	O
and	O
3D	O
graphic	O
windows	B-Application
.	O
</s>
<s>
The	O
STK	O
Integration	O
module	O
provides	O
a	O
scripting	O
interface	O
named	O
Connect	O
that	O
enables	O
STK	O
to	O
act	O
within	O
a	O
client/server	O
environment	O
(	O
via	O
TCP/IP	B-Protocol
)	O
and	O
is	O
language	O
independent	O
.	O
</s>
<s>
Users	O
also	O
have	O
the	O
option	O
of	O
using	O
STK	O
programatically	O
via	O
OLE	B-Application
automation	I-Application
.	O
</s>
<s>
Within	O
each	O
scenario	O
any	O
number	O
of	O
satellites	B-Application
,	O
aircraft	O
,	O
targets	O
,	O
ships	O
,	O
communications	O
systems	O
or	O
other	O
objects	O
can	O
be	O
created	O
.	O
</s>
<s>
STK	O
is	O
a	O
modular	O
product	O
,	O
in	O
much	O
the	O
same	O
way	O
as	O
MATLAB	B-Language
and	O
Simulink	O
,	O
and	O
allows	O
users	O
to	O
add	O
modules	O
to	O
the	O
baseline	O
package	O
to	O
enhance	O
specific	O
functions	O
.	O
</s>
<s>
STK	O
can	O
be	O
embedded	O
within	O
another	O
application	O
(	O
as	O
an	O
ActiveX	O
component	O
)	O
or	O
controlled	O
from	O
an	O
external	O
application	O
(	O
through	O
TCP/IP	B-Protocol
or	O
Component	B-Application
Object	I-Application
Model	I-Application
(	O
COM	O
)	O
)	O
.	O
</s>
<s>
In	O
practice	O
,	O
as	O
long	O
as	O
it	O
is	O
possible	O
to	O
create	O
a	O
socket	B-Protocol
connection	I-Protocol
,	O
send	O
information	O
through	O
that	O
socket	O
and	O
then	O
receive	O
information	O
that	O
way	O
then	O
STK	O
can	O
be	O
controlled	O
with	O
connect	O
using	O
that	O
language	O
.	O
</s>
<s>
Applications	O
have	O
been	O
developed	O
in	O
C	B-Language
,	O
C++	B-Language
,	O
C#	B-Application
,	O
Perl	B-Language
,	O
Visual	B-Language
Basic	I-Language
,	O
VBScript	B-Application
,	O
Java	B-Language
,	O
JavaScript	B-Language
and	O
MATLAB	B-Language
.	O
</s>
