The forward fuselage is constructed of conventional 2024 aluminum
alloy skin-stringer panels, frames and bulkheads. The panels are
single curvature and stretch-formed skins with riveted stringers
spaced 3 to 5 inches apart. The frames are riveted to the skin-stringer
panels. The major frames are spaced 30 to 36 inches apart. The Yo
378 upper forward bulkhead is constructed of flat aluminum and formed
sections riveted and bolted together; the lower is a machined section.
The bulkhead provides the interface fitting for the nose section.
The nose section contains large machined beams and struts. The
structure for the nose landing gear wheel well consists of two support
beams, two upper closeout webs, drag-link support struts, nose landing
gear strut and actuator attachment fittings, and the nose landing
gear door fittings. The left and right landing gear doors are attached
by hinge fittings in the nose section. The doors are constructed
of aluminum alloy honeycomb, and although the doors are the same
length, the left door is wider than the right. Each door has an
up-latch fitting at the forward and aft ends to lock the door closed
when the gear is retracted, and each has a pressure seal in addition
to a thermal barrier. Lead ballast in the nose wheel well and on
the Xo 378 bulkhead provides weight and center-of-gravity
control. The nose wheel well will accommodate 1,350 pounds of ballast,
and the Xo 378 bulkhead will accommodate a maximum of 2,660 pounds.
The forward fuselage carries the basic body-bending loads (a tendency
to change the radius of a curvature of the body) and reacts nose
landing gear loads.
The forward fuselage is covered with reusable insulation, except
for the six windshields, two overhead windows and side hatch window
areas around the forward RCS engines. The nose cap is also a reusable
thermal protection system. It is constructed of reinforced carbon-carbon
and has thermal barriers at the nose cap-structure interface.
The forward fuselage skin has structural provisions for installing
antennas, deployable air data probes and the door eyelet openings
for the two star trackers. Two openings are required in the upper
forward fuselage for star tracker viewing. Each opening has a door
for environmental control.
The forward orbiter/external tank attach fitting is at the Xo 378
bulkhead and the skin panel structure aft of the nose gear wheel
well. Purge and vent control is provided by flexible boots between
the forward fuselage and crew compartment around the windshield
windows, overhead observation window, crew hatch window and star
tracker openings. The forward fuselage is isolated from the payload
bay by a flexible membrane between the forward fuselage and crew
compartment at Xo 582.
Six forward outer pane windshields are installed on the forward
fuselage. They are described in the section on windows. The window
structural frames in the forward fuselage are five-axis machined
parts.
The forward RCS module is constructed of conventional 2024 aluminum
alloy skin-stringer panels and frames. The panels are composed of
single-curvature and stretch-formed skins with riveted stringers.
The frames are riveted to the skin-stringer panels. The forward
RCS module is secured to the forward fuselage nose section and forward
bulkhead of the forward fuselage with 16 fasteners, which permit
the installation and removal of the module. The components of the
forward RCS are mounted and attached to the module, which will have
a reusable thermal protection cover, in addition to thermal barriers
installed around it and the RCS engine interfaces and the interface-attachment
area to the forward fuselage.
The forward fuselage and forward RCS module are built by Rockwell's
Space Transportation Systems Division, Downey, Calif.
