television system is used primarily to support on-orbit activities
that require visual feedback to the crew. The CCTV system also provides
the capability to document on-orbit activities and vehicle configurations
for permanent record or for real-time transmission to the ground.
The CCTV system can be controlled by both onboard and remote uplink
commands. The CCTV system is a standard monochrome (black and white)
system with an optional color capability by means of interchangeable
camera lenses. Color scenes are not available on the onboard monitors
because of hardware restrictions; however, color scenes are available
on recorded and downlinked video.
to the CCTV system are available from cameras mounted at several
locations in the payload bay and on the remote manipulator system
arm, which is mission dependent.
also used in the middeck and the flight deck of the crew compartment.
The video signals from these cameras can be viewed by the crew on
one of two monitors in the flight deck, then sent to a video tape
recorder for later viewing or to the ground on the S-band FM or
The video control
unit controls power and input/output configuration, including camera
control of pan, tilt, zoom, focus, iris operations and synchronization
for the CCTV system. It processes video and data inputs from cameras
and video tape recorder channels and routes them to monitors, the
VTR or the ground by downlink.
of the CCTV system for monitoring and recording mission activities
include payload bay door operations, remote manipulator system operations,
experiment operations, rendezvous and stationkeeping operations,
and onboard crew activities.
The CCTV system
consists of the video control unit, television cameras, VTR and
onboard television monitors 1 and 2.
orbiter intercom channels A and B can be interleaved with the video
output, along with Greenwich Mean Time data from the orbiter master
timing unit. The VCU also generates a standard test pattern for
use in adjusting the monitors and verifying downlink and provides
multiplex capability for two split-screen outputs.
cameras are identical with the exception of accessory hardware.
Any camera can be equipped with three types of interchangeable lens
assemblies, depending on mission requirements. Both monochrome and
color lenses are available with normal field of view. Color lenses
are also available with a wide-angle field of view. In addition
to focus control for sharp images, several special lens control
functions are available. All functions can be controlled by both
onboard and ground uplink commands.
light control is available for each camera. Its modes compensate
for scene brightness by eliminating a fraction of the brightness.
It then adjusts the light level of the scene by controlling (1)
the silicone intensified target tube high voltage, (2) lens aperture
(iris) and (3) automatic gain control. As a result, more detail
and contrast are available in the brighter areas of a scene. Light
or dark areas of a camera scene can be enhanced or subdued by means
of gamma commands. More contrast can be obtained within light or
dark areas. Zoom capability magnifies or reduces the size of objects
in a camera's field of view by adjusting the focal length of the
lens. The minimum focus for standard lenses is 3 feet, the maximum
payload camera bay inputs can be used per mission, more than five
camera locations are available. If a mission requires a keel camera,
only one camera can be positioned at one of four locations along
the keel. If a camera is connected to the keel/EVA position, then
TV camera views are not available while the EVA camera is in use.
Each remote manipulator system can accommodate two cameras, mounted
at the wrist and elbow locations; however, scenes are only available
from either the wrist or the elbow, selectable by means of panel
With the exception
of the RMS wrist camera and keel camera, all exterior cameras are
mounted on motor-driven pan-tilt units. Camera azimuth (left and
right) position and elevation (up and down) from a reference can
be controlled on board by the flight crew or by ground uplink. The
front tilt unit can accommodate up to plus or minus 170 degrees
of pan and plus or minus 170 degrees of tilt from center. In tilt,
the cameras cannot look straight down; in pan, the cameras cannot
look straight down or straight back, which accounts for the range
of 340 degrees instead of 360 degrees. The pan and tilt units move
at two speeds: the high rate allows 12-degree-per-second rotation,
and the low rate allows 1.2-degree-per-second rotation. Each pan
and tilt unit contains a thermostatically controlled heater to maintain
Up to three
cameras can originate from payload sources. These inputs can come
from pallet-mounted cameras or from the Spacelab module during a
Spacelab mission. If the payload cameras are part of the orbiter
flight hardware, the video control unit can command the camera in
focus and zoom. However, Spacelab provides the electrical interface
camera outlets that are available inside the orbiter crew compartment
for portable cameras. The flight crew would deploy, set up and stow
the portable TV system.
cameras are equipped with a color lens. Monitors 1 and 2 and the
TV viewfinder monitor provide a monochrome output regardless of
the lens assembly utilized, allowing the crew to adjust and view
the video scenes. The flicker that appears in the interior camera
scenes is caused by the rotating color wheel used to generate the
field-sequential color signal that allows color outputs on the ground.
The color-conversion process on the ground eliminates the flicker
before the color signal is distributed.
The basic monochrome
camera converts light images into a composite video signal (picture
plus sync) and can produce either a black-and-white or color image,
depending on the lens assembly used. The lens provided with the
TV system is an f/1.4 color zoom lens equipped with a six-segment,
three-color rotating filter wheel that produces sequential red,
green and blue color fields. Motorized lens control functions that
vary the zoom, iris and focus are controlled manually by lens switches
remotely from panel A7 or by ground command. The small portable
monochrome viewfinder monitor (8 by 4.25 by 3.6 inches, weighing
4 pounds) enables the crew to view camera video output for picture
quality and scene verification when monitors 1 and 2 are not accessible
or available. The TV cable connects the camera and the two TV system
input stations located in the crew cabin at panels O19 and M058F.
The cable provides the camera with 28-volt dc power; camera and
lens commands along with the sync signal; and video, including camera
and lens data, to the control unit for distribution. The viewfinder
monitor cable, which is 9 feet long, provides an interface between
the camera and the monitor.
mounts restrain the camera assembly where it is used. Fixed-location
quick-shoe mounts interface with any smooth, flat crew compartment
surface. Clamp adapters can be used to affix the camera to panel
switch guards or handholds. In addition, a special baseplate can
be attached to either of two mounting locations on the sills of
overhead windows 9 and 10.
The two black-and-white
TV console monitors in the aft flight deck crew station on panel
A3 are identical and are arranged one over the other. The top one
is monitor 1 and the bottom is monitor 2. The monitors are used
to view video on board. Camera scenes from any exterior, interior
or payload camera can be viewed on either monitor. The video being
downlinked can also be observed on either monitor. In addition,
the monitors can be used to view the video being recorded or played
back on the VTR. They can also display cabin TV output when it is
more convenient than using the viewfinder monitor.
accommodates a split-screen image from any two cameras. This feature
is generated by the control unit and selected by panel A7 commands.
Alphanumeric displays of camera location, pan and tilt angles, and
temperatures of any cameras in an overtemperature condition can
be superimposed on the monitor scene. A cross hair is also available
at the center of the screen as an aid in remote manipulator system
and proximity operations. The monitors are equipped with displays
and controls for direct control of most monitor operations; however,
the assignment of an input source to the monitor is controlled by
panel A7. Each monitor is 12.5 by 10 by 7 inches and weighs 21 pounds.
The video tape
recorder is a cassette recorder with the capability to record both
video data and voice annotation. Video from any camera source can
be recorded on board and in color if the selected camera has color
capability using off-the-shelf cassettes of 20 and 30 minutes. Voice
annotation can be input directly to the VTR through a headset interface
unit. The HIU interfaces only with the VTR, not with the vehicle
communications system. A tone may also be recorded to identify a
particular location for subsequent playback operations. Voice annotation
can be added during playback and records over any previously recorded
VTR operations must be performed by the crew-everything from tape
changeout to VTR activation. The VTR is configured to receive its
video input from monitor 2 (to record video on the VTR, the desired
camera output must be displayed on monitor 2, which is connected
directly to the recorder). For onboard playback, the recorded video
can be reviewed on monitor 2 by positioning its source switch to
direct and initiating a playback mode. For downlink purposes, the
VTR is connected to the payload 1 input, which is a panel A7 video
input selection. The switch panel located above the VTR includes
a circuit breaker for the recorder. The recorder is equipped with
a no video light that is illuminated when no video source is present
at the recorder. When recording, the operator should verify that
the no video light is off. An end of tape light indicates when the
cassette is out of tape, and the VTR automatically stops. Tape changeout
is simply a matter of ejecting the cassette from the recorder.
mobility unit TV is a fully portable remote television unit. It
transmits black-and-white television pictures to the orbiter CCTV
system from virtually any location outside the orbiter. Orbiter
reception is through either of the S-band FM hemispherical antennas.
The TV assembly fits over the EMU helmet and light assembly. It
is battery powered (28 volts dc) and transmits video at 1,775.7
MHz to a video receiver/processing unit installed in the orbiter's
middeck. When the receiver is connected to the TV input station
at panel M058F by a standard 20-foot TV power cable, crew members
can view real-time EVA video on either monitor by selecting the
middeck camera input on panel A7. EVA video can also be selected
for return link or taping.
to improve scene quality is available for both exterior and interior
cameras. In the payload bay, floodlights are mounted on the forward
bulkhead and at various locations along the lower payload bay interior.
A spotlight is also connected to the RMS wrist. These lights are
controlled from panel A7.
can be downlinked by means of onboard or uplink commands. If a scene
assignment for downlink is commanded through S-band or Ku-band uplink,
the appropriate camera command is received through the network signal
processor by the orbiter general-purpose computer. The GPC then
transmits the command to the control unit on payload MDM PF2. The
control unit selects the desired camera video and combines it with
intercom A or B (if desired) and then sends a composite signal to
the FM signal processor.
The FM signal
processor transfers the TV signal to the FM transmitter, which modulates
the signal and transmits it to a ground station with TV capability.
Video data consisting of one of four signals (including real-time
TV, main engine data, recorder dumps and payload data) can be individually
assigned for downlink to the single S-band FM wide-band channel.
Thus, if one of the other sources is being downlinked, video cannot
be transmitted to the ground simultaneously.
station receives, processes and records the downlinked TV signal.
Real-time TV can be transmitted directly from the ground station
to the Mission Control Center through a relay satellite. Sites with
TV capability are Merritt Island, Goldstone and Hawaii.
Ku-band system can downlink TV signals through the TDRSS directly
to the Houston Mission Control Center. Since the TDRSS is not restricted
to specific tracking stations, more continuous TV capability is
available. However, only one Ku-band FM channel is used to downlink
real-time TV, main engine data, recorder dumps and payload data.
Therefore, video cannot be transmitted if one of the other sources
is being downlinked.