Observatory
CDR, Bulkhead Assembly, Galley Subcontract
The SOFIA team successfully completed
the observatory's Critical Design Review on Thursday, August
17, marking a major SOFIA milestone.
The four-day review took place in
Waco, Texas, where Universities
Space Research Association (USRA) subcontractor Raytheon
Aircraft Integration Systems is modifying the aircraft to
house the telescope. Over 100 attendees from the U.S. and Germany,
including reviewers from NASA and several external independent
review boards, met to hear presentations on all aspects of SOFIA
design.
Topics included aircraft modification,
systems integration, the science operations center, testing,
and safety requirements, along with a summary of the successful
telescope CDR held in April in Germany. Also under review was
the program schedule, including the manufacturing of all components
within the scheduled plan.
Critical Design Reviews are one-time-only
events in the lives of space agency programs around the world,
serving as bridges between design and manufacturing stages. A
successful review means that the design is validated and will
meet its requirements, is backed up with solid analysis and documentation,
and has been proven to be safe.
Artist's rendering of the fore and aft bulkheads
in relation to the telescope.
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Meanwhile, inside Raytheon's Waco
facilities, one of the more intriguing current activities is
the fabrication of fore and aft bulkheads separating the telescope's
open port cavity from the cabin and from the very back of the
plane, known as the aft equipment bay.
The aft bulkhead, which is being
built first, is approximately 21 feet in diameter and 10 inches
thick. Basically a huge, normally unpressurized wall taking up
the entire inside circumference of the plane, it's been designed
to withstand more than 100,000 pounds of pressure (the pressurized
fore bulkhead, on the other hand, has been designed to withstand
more than 1 million pounds of pressure). To date, the production
crew has assembled 651 parts into 78 sub-assemblies, using more
than 8,800 fasteners.
Initial assembly is taking place
on the hangar floor, rather than inside the aircraft. Final assembly
will take place inside the plane as part of the installation
process, scheduled to begin this October.
Artist's rendering of the fore and aft bulkheads
in relation to the telescope.
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It's critical for these bulkheads
to be so perfectly flat that the normal cement floors of the
Raytheon hangar, which certainly seem flat to the untrained eye,
aren't level enough to serve as a bulkhead assembly area. So,
to accomplish the flatness requirements, a special area 25 feet
square, specially built flat to a tolerance of plus or minus
.040 inches over 25 feet, has been poured near the aircraft and
a protective layer of equally level plywood applied. Once the
aft bulkhead is installed, the team will begin assembly of the
forward bulkhead using the same flat surface.
Coffee, tea, or...? Raytheon has
awarded a subcontract to B/E
Aerospace Inc., based in Jacksonville, Florida, to create
the galley section of the SOFIA plane. No, there won't be flight
attendants on the aircraft, but at least the scientists, engineers
and educators in the cabin will have a nifty new refrigerator,
microwave and coffeemaker at their disposal.
That's quite a step up from SOFIA's
predecessor, the Kuiper Airborne Observatory, a modified C-141
military plane that flew from 1974 to 1995. Adventurous souls
on that scientifically significant observatory, which admittedly
left a bit to be desired in the amenities department, had only
a small, used refrigerator and oven--along with their own carry-on
coolers--to get them through each night's flight.
B/E Aerospace's interior systems
products have been selected for use by virtually every airline
in the world, making the company an industry leader in interior
systems design, development and manufacture.
Sept 10, 2000
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