The Auxiliary Control Room

Joined: April 29th, 2007, 8:38 am

May 29th, 2013, 2:22 pm #1

Control Room

Auxiliary Control Room (ACR) in Star Trek was a welcome addition to the already
established Enterprise
sets.   Practically, in real world
applications; it only makes sense to have a secondary control area in case the
bridge was damaged or for some reason it became uninhabitable.  The problem of course in Star Trek was that
there never seemed to be any security around that vital area of the ship and
all too often the ACR would be used to take over the ship from our crew. 

Space hippies use the ACR to take over the ship in the episode "The Way to Eden"

ACR was a roughly diamond shaped room with a large semi-circular desk (with
three separate control panels on top) that faced a viewscreen located at the
front of the room.  On the right side it
also had a separate section behind a screen wall that contained a large
engineering console.  This engineering
console was actually from the first season engineering set.  For the second season the engineering set was
modified by removing one of the three 8’ sections that made up the bank of
engineering consoles.  A ships ladder was
added in the middle of the remaining two consoles and the set was shortened
slightly.  The console that was removed
is what we saw in the ACR.  Another feature
of the ACR was a smaller console and status board that was located between the
viewscreen and the screen wall.  Also
noteworthy was a nice arch that followed the angled sidewall of the view screen
and continued overhead and connected to the screen wall; next to the outer wall
of the ACR.  As with most TOS sets; cost for constructing the ACR set were kept down by using many 
recycled components – the viewscreen is from the 2 pilot
episodes’ Bridge (last seen in the Briefing Room during “Space Seed”) and the
status board next to it is full of recycled set components including a type 4A computer prop.  In addition, the red metal
grates appeared in numerous season 1 episodes in the corridor set, usually
opposite the Briefing Room.  In fact, the only truly original piece of the ACR set is the
central control desk!

Our first look at the ACR aboard the starship "Constellation" from the episode "The Doomsday Machine"

ACR was not seen at all in the first season which is why Khan had to take over
the ship from the Engineering section in “Space Seed.”  It was however, seen throughout the second
and third season in various episodes.  It
first appeared in the episode “The Doomsday Machine” on board the starship
“Constellation.”  The reason
for it appearing in this episode at all was for production reasons as detailed in a memo dated April 10th, 1967 from Bob Justman to Gene Roddenberry noting the confusion to the audience if both Kirk and Decker were both on the bridge of different ships.  Since most of the “Enterprise”
scenes were on the bridge; they would not have the time in the 6 day schedule
to film all of the “Enterprise”
bridge scenes and then distress the set to appear as the damaged
“Constellation” bridge and then get it ready for the following episode.  It was much easier and much less confusing to the audience to have a secondary
control area (separate set) which did not resemble the bridge to film those portions of the “Constellation” scenes
in because it did not have to be repurposed during shooting of the episode.  Certainly the producers realized the advantage
of having a set of this nature and other scripts that it could be used in.  The ACR became a semi-permanent set since it was located in an area of the sound stage that didn't interfere with any of the standing sets.

More detail was added to the status board the second time we saw the ACR in the episode "The Changling"

ACR was a great looking set and was used again just a few episodes later when
we saw it in the episode “The Changling.”   In this episode one of the metal grating
sections was removed from the screen wall; allowing direct access to the
engineering console located behind the screen wall.  In “The Doomsday Machine” the crew had to go
out into the corridor to enter the engineering console section; this
area-to-area access makes a lot of sense.  Besides changes in set dressing to the ACR which
mostly was the random location of various vertical conduits; it seemed to
change very little through out the series (well at least on this set).  During filming of the series there were
actually two different Auxiliary Control Room sets that were used located in
different areas of the sound stage. 


you have ever seen the commercially available set blueprints you will notice that the ACR is not shown
on them.  So just where was this set
located?  The ACR set as we have seen it
in these first two episodes was a semi-permanent set located behind the
briefing room set and the layout of this set stayed basically the same as when
we first saw it.  The ACR did make two
other appearances in the second season but those scenes were shot at a
different area of the stage.  In both “I
Mudd” and in “By Any Other Name” the ACR was moved to the swing-set portion of
the permanent standing sets.  This location
was adjacent to the engineering set and was most commonly used as the brig but
served as many different areas of the ship. 
We know this is a different set for several different reasons.


we first saw the ACR the entry door was a 4’ wide double door.  In “I Mudd” and “By Any Other Name” the door
was a 3’ wide single door.  When Norman enters the ACR we
can see the outer part of the corridor and we can see the tell-tale red
“doorbell” at the swing set door and also the overhead conduits match up as
well.   It seems that when they needed to
film the left side of the room they used this set and when they filmed the
right side of it they would use the semi-permanent set by the briefing room (However, the right side did not appear in either “I Mudd” or “By Any
Other Name”).  
Neither set apparently had walls which
completed the room but both were open for the camera on the opposing side.  The same control panel and status board section
on the right of the screen from the original set was moved to the other
side of the room at the swing-set location. 
This gave the illusion that there was a control console on both sides of
the veiwscreen; but it was actually the exact set.  In addition to the change of the control panel/status
board; the circular table with its control panels is also present in this
version of the ACR.  Other than some
changes in set dressing the room (set) appears the same in both the later
episodes.  In the episode “By Any Other
Name” this same set was actually called “Life Support Control” but it was the
same ACR set that we saw in “I Mudd.”  
The added detailing on the walls of the set in "By Any Other Name" make it apparent that this was meant to appear as a different room than the ACR.  This set layout was never used again after “By Any Other Name.”

The latter second season episodes used the swing-set location for the ACR 

the third season; all filming of the ACR was done in the semi-permanent set
near the briefing room which was the original location of it when the ACR made
its debut.  The set essentially stayed
the same with the exception of the engineering console front panel which was
painted gray instead of the red that it had been since the beginning of the
This color change was because it was redressed to appear in the Romulan engine
room in the episode “The Enterprise Incident."  When the console was pressed into service again in the ACR during
the next filmed episode “And the Children Shall Lead” it seems no-one
bothered to return the original color scheme.  
metal grating that was removed in “The Changling” reappeared in the third
season blocking off the engineering console from the main ACR room.  We do see however, an alternative way into
the compartment in the episode “And The Children Shall Lead” which was adjacent
to the viewscreen and used by one of the children. We probably get the most comprehensive
view of the ACR and the adjoining corridor in “The Way to Eden" when the space hippies take over the "Enterprise."  The corridor as seen in earlier episodes was
just a small section outside of the ACR meant only to be filmed from inside
looking through the doors.  In “The Way
to Eden" a
larger section of corridor was built to show the outside of the ACR from the
corridor.  It is interesting to note that
the ACR corridor was apparently only 6’ wide as compared to the permanent
corridor which was 8’ wide.

This corridor was not part of the permanent set but was a small section built just outside of the ACR


actually is very little documentation on the ACR and the only hint we have
about it is from the book “Star Trek Sketchbook; The Original Series” in “The
Lost Set” section.  On Matt Jefferies
scaled model of the set we see the ACR and its location.  We can extrapolate size information by
comparing know dimensions of certain parts of the set but still there are a lot
of unknowns about this very cool set. 
The ACR has never been illustrated as part of the set on any known
official set drawings from the original production.  The illustrations here are based on the best
available information and are accurate to a point but 100% accuracy cannot be
attained unfortunately.

So next time you
see the ACR notice what a cool set it was.

Special thanks the Matthew "Mytran" from the Trek BBS for his help in proofing and contributing to this ACR article








Last edited by feek61 on August 29th, 2014, 11:27 am, edited 22 times in total.

Joined: April 29th, 2007, 8:38 am

November 11th, 2013, 1:31 pm #2

Here is the final version (third season) of the Status Board with its Type 4A Beta computer.
Last edited by feek61 on November 12th, 2013, 8:52 am, edited 1 time in total.

Joined: April 29th, 2007, 8:38 am

March 14th, 2014, 12:40 pm #3

Each time that we saw the ACR in an episode it was different in some way. This is "The Doomsday Machine" configuration (sans battle damage) which was the first time that we saw this set. This version will be our base-line in covering the changes throughout the series.  In the rendering there is a door shown entering the ante-room where the engineering console is located. Even though this is never seen in the episode; Scotty does go into the corridor and emerges behind the screen wall from that direction so we can assume there had to be a door there . . . at least in this episode!!!  
Looking forward from the entry door to towards the viewscreen (desk & control consoles are not shown)
This is the side wall (desk and control consoles not shown)
The back wall showing the unseen phantom door into the ante room.
Last edited by feek61 on April 18th, 2014, 12:25 pm, edited 3 times in total.

Joined: April 29th, 2007, 8:38 am

April 18th, 2014, 9:01 am #4

In the episode "The Changeling" is the first time we see the ACR when it is suppose to be on the "Enterprise."  It was of course the same set as seen in "The Doomsday Machine" just clean-up but there were a few changes between the two.  The most obvious change is the elimination of one of the hex screens that separate the engineering console from the main ACR room.  This allows the technician to walk freely back to the console were before Scotty had to go out into the corridor to enter the room.  Also, on the status board the Type 4 A "Alpha" has been installed (see this link for details on the TOS computers ... -and-in-HD) .  
Last edited by feek61 on April 18th, 2014, 12:27 pm, edited 2 times in total.

Joined: April 29th, 2007, 8:38 am

April 18th, 2014, 10:17 am #5

The next time the main ACR set is shown is in the third season episode "And the Children Shall Lead."  There are several changes from the last time we saw the set back in season 2.  During the filming of "The Enterprise Incident" the engineering console from the ACR was used in the room where the Romulans kept the cloaking device.  The red/orange front was painted a light gray/pale yellow for that episode and it remained that color for the rest of the series after the console was moved back to the ACR set.  To add a little more color to the set; the column between the hex screen was painted the red/orange color.   The two wall-plants that were on the left side of the door on the back wall were removed and there was some new detail added.  One of the two pipes that was by the status board in the second season was added on this wall and in addition; around the bottom portion of the pipe two semi-circular screens were added.  To the right of pipe there was a new wall-plant added.  This appears to be a box that light bulbs were packed in and in fact there appear to be light bulbs in a few of the holes.  On the status board there are lines added.  Actually these were added back in the episode "By Any Other Name" when the status board was used in the alternate ACR set which substituted for Life Support but this is the first time we see them in the main ACR set.  Also, the computer in the status board has been changed from the Type 4 A "Alpha" to the Type 4 A "Beta" since "The Changeling" episode.  
Last edited by feek61 on April 18th, 2014, 12:32 pm, edited 1 time in total.

Joined: April 29th, 2007, 8:38 am

April 18th, 2014, 10:53 am #6

The last time the ACR set is shown was in the episode "The Way to Eden" and this last appearance showed us further modification to the set.  In fact, this episode had the most changes and gave the ACR a little more screen time which may have been the reason for the extra attention given to detail the set.  The pipe added in "And the Children Shall Lead" by the door is still there but an additional semi circular screen has been added above the two that were there previously.  Also, the wall-plant to the right of the pipe has been removed.  There has been a "door bell" added by the entry door which was the same resin buttons as we saw on the bridge set.  Here we have two green above two red combinations to form the "door bell."   The red column seen in the previous episode has now been painted gray again but the arched beam has now been painted pale yellow.  Also a yellow pipe was added back behind the hex screen to the right of the engineering console.   The display panels on the engineering console have been changed.  It appears that the front of the large center display has been removed leaving only the back sliding element (the light changes were created by two sheets with holes drilled into them; this appears to be only the back section).  Also, the right display console has been replaced with one from the original season 1 engineering set.  Star Trek never threw away anything and this piece was probably just laying around so they used it.  Also, a new pipe has been added to the left side of the hex screen.
Last edited by feek61 on April 20th, 2014, 6:44 pm, edited 2 times in total.

Joined: April 29th, 2007, 8:38 am

May 17th, 2014, 2:06 pm #7

Here are a couple of views without the arched opening so you can see what the room looked like without it in the way.
Last edited by feek61 on May 17th, 2014, 2:35 pm, edited 1 time in total.

Joined: April 29th, 2007, 8:38 am

March 9th, 2015, 11:00 am #8

The the Star Trek Continues episode "Fairest of them All" we built the Auxiliary Control Room Set (here is a link to the episode in case you have not seen it: )

Although the ACR has always been one of my favorite sets; there is very little set information available other than the screen caps. This made getting the design right a challenge; which I love! :)/>/>/> I had done the research about a year or so before I knew that we would need the set for STC's "Fairest of Them All" so when I read the script I was excited and ready to start building. We started out by laying out the walls and after it was laid out; I taped the outline.

Here is the set after it was laid out showing the cool angles of the set

One of the very cool features of the ACR is the circular desk. Even though we never saw it apparently the shape was meant to allow the center control panel to slide around the table top to different locations. Here we are building the table and table base which was just a radius wall under the table top (just like on the original set).

Getting the basic structure-up was pretty cool. For this episode we redid the transporter room so part of the ACR was made-up of the old transporter room wall flats; hence the color. This day the high temperature was about 30 degrees; it was freezing!

Lots of filling and sanding is needed on the sets; here we see some of the filling and other progress shots.

Here we are holding up the hex grid . . . just to see what it looks like! One thing about the hex grid is that it is NOT rigid. It's like holding-up a wet noodle. The material is designed to flex and is very heavy. The only thing that keeps it standing is the outer frame.

Here is the set with the table set in place.

Here are a couple of photos of the control panels being built. All three of them were "heros" with working lights and switches. On the main control panel all of the rocker switches controlled the lighting and the rotary switches would change the light colors and sequences so that numerous combinations could be used giving us some variety. For example if the ship was in distress we could show the lighting all red or flashing red or all green if everything was good. We never really saw much of anything in the way of lighting on these in TOS but it only made sense to make them light-up and appear functional for STC.

The inside of the main control panel during the wiring. The power supply for all three control panels was a 9v battery.

This was a couple of days before filming began and just before I took them to the studio

Here are some more photos a day or two before we filmed on the set.

Yes, we did have a viewscreen; we just never saw it in the episode.

This is the entrance door to the ACR room. Two things to note; in the episode the corridor outside was green screened in and was not actually there (and also the corridor shots showing the ACR inside were also green screened). Also, the yellow set-dressing to the right of the door are actually packing from my printer. When I pulled the printer out of the box I immediately thought the packing looked like something we would see on the wall of the TOS set, so we painted them and stuck them on the wall. While they don't exactly match what was there in TOS; they are certainly close enough particularly since I don't think they were ever seen on screen either, lol.

I hope you enjoyed these photos!!

Joined: November 10th, 2009, 9:45 am

April 1st, 2015, 12:45 am #9


That is stunning! What a recreation!!

Steve P

Joined: November 22nd, 2017, 2:16 pm

November 22nd, 2017, 6:04 pm #10

Thanks for writing it up, really enjoy the info.