yee@trident.arc.nasa.gov (Peter E. Yee) (11/22/90)
Bruce Buckingham
407/867-2468 Nov. 14, 1990
KSC RELEASE NO. 181 - 90
WORK ON HYDROGEN DISPERSION SYSTEM COMPLETED ON MOBILE LAUNCHER
PLATFORM
Following a series of liquid hydrogen leaks on the orbiters
Columbia and Atlantis this past summer, an external tank/orbiter
umbilical hydrogen dispersion system was recently designed and
installed on one of three mobile launcher platforms at Kennedy
Space Center.
The system, now installed on mobile launcher platform number
two in the Vehicle Assembly Building, will also be installed on
the remaining two MLPs following their current assignments to
support Space Shuttle missions this year.
The dispersion system is designed to provide a nitrogen rich
air flow around the hydrogen 17-inch disconnect line which is
located between the orbiter and external tank. The system
consists of a supersonic gaseous nitrogen nozzle, a nozzle
support pipe, a blast cover, and a 2-inch gaseous nitrogen supply
line.
The dispersion system was designed to reduce oxygen present
and disperse hydrogen concentrations from a potential leak of up
to 17,000 scim (standard cubic inches per minute) or 10 scfm
(standard cubic feet per minute). The system will provide
sufficient air flow around the 17-inch disconnect to prevent
hydrogen concentrations from exceeding four percent. Hydrogen
concentrations greater than four percent in an oxygen-rich
environment present a potential hazardous situation.
The nozzle on the dispersion system is made of stainless
steel and was designed to provide for a supersonic volumetric
flowrate of 750 scfm at 125 psi.
Firing room personnel will be able to control the dispersion
system from the Launch Control Center. From the LCC, varying flow
rates of the dispersion system and nozzle adjustments can be
operated remotely. The system is scheduled to be available for
use during the launch of Discovery on Shuttle mission STS-39.
NASA and Boeing Aerospace Operations were responsible for
the design and construction of the system's nozzle components.
Engineers for NASA and the architect and engineering firm of
Reynolds, Smith and Hills were responsible for the design of the
structural supports for the nozzle and supply line.