<s>
The	O
ASC-15	B-Device
(	O
Advance	O
System	O
Controller	O
Model	O
15	O
)	O
was	O
a	O
digital	O
computer	O
developed	O
by	O
International	O
Business	O
Machines	O
(	O
IBM	O
)	O
for	O
use	O
on	O
the	O
Titan	O
II	O
intercontinental	O
ballistic	O
missile	O
(	O
ICBM	O
)	O
.	O
</s>
<s>
The	O
storage	O
was	O
a	O
drum	B-General_Concept
memory	I-General_Concept
.	O
</s>
<s>
Electronic	O
circuits	O
were	O
welded	O
encapsulated	O
modules	O
,	O
consisting	O
of	O
discrete	O
resistors	O
,	O
transistors	B-Application
,	O
capacitors	O
,	O
and	O
other	O
components	O
welded	O
together	O
and	O
encapsulated	O
in	O
a	O
foam	O
material	O
.	O
</s>
<s>
The	O
first	O
inertial	O
guidance	O
system	O
for	O
the	O
Titan	O
II	O
was	O
built	O
by	O
AC	O
Spark	O
Plug	O
,	O
and	O
included	O
an	O
inertial	O
measurement	O
unit	O
based	O
on	O
designs	O
from	O
Draper	O
Labs	O
at	O
MIT	O
,	O
and	O
the	O
ASC-15	B-Device
computer	O
designed	O
and	O
built	O
by	O
IBM	O
in	O
Owego	O
,	O
NY	O
.	O
</s>
<s>
The	O
AC	O
Spark	O
Plug	O
system	O
,	O
including	O
the	O
ASC-15	B-Device
,	O
was	O
replaced	O
by	O
the	O
Delco	O
Electronics	O
Universal	O
Space	O
Guidance	O
System	O
(	O
USGS	O
)	O
on	O
operational	O
Titan	O
II	O
missiles	O
starting	O
in	O
January	O
1978	O
.	O
</s>
<s>
The	O
ASC-15	B-Device
was	O
built	O
on	O
an	O
aluminum	O
frame	O
about	O
1.5x1.5x1	O
feet	O
.	O
</s>
<s>
These	O
surrounded	O
a	O
bell	O
frame	O
housing	O
a	O
drum	B-General_Concept
memory	I-General_Concept
.	O
</s>
<s>
The	O
ASC-15	B-Device
was	O
kept	O
as	O
the	O
vehicle	O
guidance	O
computer	O
,	O
but	O
the	O
drum	O
was	O
lengthened	O
slightly	O
to	O
provide	O
78	O
usable	O
tracks	O
,	O
an	O
increase	O
of	O
20	O
over	O
the	O
drum	O
used	O
in	O
the	O
Titan	O
II	O
.	O
</s>
<s>
The	O
ASC-15	B-Device
was	O
first	O
flown	O
on	O
SA-5	O
,	O
the	O
first	O
Saturn	O
I	O
Block	O
II	O
vehicle	O
and	O
the	O
first	O
to	O
achieve	O
orbit	O
.	O
</s>
<s>
The	O
passenger	O
system	O
was	O
the	O
ASC-15	B-Device
and	O
the	O
ST-124	O
inertial	O
platform	O
.	O
</s>
<s>
On	O
SA-6	O
,	O
while	O
open	O
loop	O
ST-90S	O
guidance	O
was	O
used	O
for	O
the	O
first	O
stage	O
(	O
S-I	O
)	O
,	O
after	O
separation	O
the	O
ST-124	O
and	O
ASC-15	B-Device
used	O
path	O
adaptive	O
guidance	O
(	O
closed	O
loop	O
)	O
to	O
control	O
the	O
second	O
stage	O
(	O
S-IV	O
)	O
.	O
</s>
<s>
The	O
arrangement	O
of	O
the	O
ST-90S	O
and	O
ST-124	O
systems	O
(	O
including	O
the	O
ASC-15	B-Device
guidance	O
computer	O
)	O
on	O
SA-6	O
is	O
shown	O
in	O
Figure	O
6	O
.	O
</s>
<s>
The	O
digital	O
computer	O
is	O
the	O
ASC-15	B-Device
.	O
</s>
