July-August 1983:Spacelab preparations

While Shuttle Orbiter Challenger has been grabbing the headlines, the first orbital ship. Columbia,
has been quietly undergoing modifications to convert it from a flying test bed and prepare it for the
important Spacelab mission this autumn.

Columbia is being modified at the Kennedy Space
Center in Bay 2 of the Orbiter Processing Facility. In
general terms, the changes will enable Columbia to
carry Spacelab and accommodate the six-man crew.
Other systems have been upgraded for added reliability
and extended lifetimes.
An airlock and tunnel adapter so that astronauts and
payload scientists can go back and forth between the
Columbia and the Spacelab has been added. Oxygen
lines will be routed from Columbia to the workshop
where it will be mixed with the Spacelab's own nitrogen
system to provide a breathable atmosphere.

Columbia's fifth flight (STS-5 in November 1982)
carried the first four-man crew. The pilots' ejection
seats, which have not been removed, limit the amount
of room up on the flight deck so two more seats have
been installed down on the mid-deck. They are of the
same type of airliner-type chairs used on STS-5 for
passengers, and are standard equipment on Columbia's
sister ship. Challenger.

Since there are more people on board, a number of
the modifications are to provide the crew with the
comforts of home. A kitchen was installed in the
mid-deck to serve as an eating and food storage area.
A large rack of development flight instrumentation
was removed to make room for the modern space
kitchen. A personal hygiene station was also added
in the area.

Since the crew will work and sleep in 12-hour shifts,
three bunk beds were installed on the other side of the
mid-deck with sleeping bag restraints. Three
hammock-type sleeping bags were also included.
More people means more equipment, so additional
permanent lockers and compartments were added,
many of them under the mid-deck floor. Changes were
made to provide adequate breathing air for the larger
crew and portable oxygen systems were installed for
the added crewmen.

To handle the additional Spacelab power requirements and to provide an abundant supply of liquid
reactants which can be converted into breathing air for
the crew, several major changes were made to the
power reactant storage and distribution (PRSD) system.
The three standard two sub-stack fuel cells, which
provide electrical power, were replaced with fuel cells
that have three sub-stacks, thus increasing the available
voltage margin. The number of cryogenic storage tanks,
which hold and supply the super cold reactants to the
fuel cells, is being increased from three to five sets. All
five of the oxygen tanks are new, designed for added
durability and reliability over the 100-mission lifetime
of Columbia.

Some of the other modifications include: a new set
of stronger main landing gear wheels, plus a modified
set of brakes; between 400 to 600 payload bay insulation blankets were replaced with blankets made of
a stronger, more heat resistant material and the
heat-rejecting radiators inside the cargo doors were
replaced with new diffuse coated radiators for reduced
glare and better heat-rejecting capability.
Other items include some 100 electronic "black
boxes," the reinforced carbon-carbon panels on the
leading edge of the two wings and several antennae.
The carbon-carbon panels are going back to their
manufacturer for treatment to increase their resistance
to oxidation and increase their mission life.
Many of the "black box" changes are to upgrade
Columbia's instrumentation systems and because of
the removal of the development flight instrumentation.

Substantial rewiring added about 100 more measurements previously undertaken by the development
instrumentation to the Orbiter's Operational Instrumentation System. A text and graphics unit was added to allow black
and white facsimiles to be sent to the Orbiter from the
ground. The unit will also receive digital data from the
Ku-band signal processor and supply the crew with a
hard copy of the processed data.

Three of Columbia's tactical air navigation (TACAN)
units, used as an external navigation aid during reentry, were replaced with upgraded units, and the four
quadrant S-band antennae were replaced with new
antennae to communicate with the Tracking and Data
Relay Satellite.
The S-band system, which has a larger beam width
compared to the narrow pencil beam of the Ku-band
system, will be used to lock on to the Tracking and
Data Relay Satellite. Once the S-band signal is acquired,
the Ku-band signal can be turned on.
A new Ku-band antenna will be used specifically for
transmitting Spacelab information down to the ground
via the TDRS satellites.

Columbia's engine subsystems also received a thorough going-over. The twin Orbital Maneuvering System
pods and the forward Reaction Control System were
removed and processed in the Hypergolic Maintenance
Facility. The three main engines are being overhauled
for use on the fourth Orbiter, Atlantis. These engines,
which operated at 100 per cent of rated thrust on
Columbia, will be modified and retested to certify them
for operation at 109 per cent aboard Atlantis. Columbia
has a brand new set of main engines and additional
leak detection development was added in the engine
compartment.
While in the Orbiter Processing Facility technicians
removed and densified more of the thermal tiles that
have not previously undergone the strengthening process. About 2,400 tiles, all on the belly area, were
treated.

Spacelab will be installed in early August and tests
conducted to verify proper operation of the integrated
vehicle. Columbia is scheduled for a late August to
early September move to the Vehicle Assembly Building
for mating with its boosters and External Tank.