COBRA, one of the engines being considered for the next generation reusable
launch vehicle, has recently completed its preliminary design review
for NASA’s Space Launch Initiative – a technology development effort
to establish reliable, affordable space access.

short for Co-optimized Booster for Reusable Applications, is a reusable,
hydrogen-fueled liquid booster and second stage engine with a thrust
level of 600,000 pounds of force. The engine is being developed by Pratt
& Whitney-Aerojet Propulsion Associates – a joint venture of Aerojet
of Sacramento, Calif., and Pratt & Whitney Space Propulsion of West
Palm Beach, Fla.

preliminary design review is a lengthy technical analysis that evaluates
the engine design to ensure achievement of system requirements and Space
Launch Initiative (SLI) goals of improved safety, reliability, cost
and operability.

review is conducted when the engine design is approximately 50 percent
complete and engine drawings are approximately 10 percent complete.
“The review is the first of several major system engineering control
gates to evaluate where we are, and to make sure we are on the right
path to produce a rocket engine prototype that will be simple to operate
and inherently reliable and thus low cost,” said Jim Snoddy, project
manager for COBRA at NASA’s Marshall Space Flight Center in Huntsville,

COBRA is a single fuel-rich preburner, staged combustion engine using
liquid oxygen and liquid hydrogen as propellants. The engine aims to
provide a 100-mission life span with a 50-mission maintenance check-up
interval. Using an inherently reliable engine cycle and numerous state-of-the-art
technologies derived from the Space Shuttle Main Engine, the COBRA engine
fuses the knowledge and experience of the first generation Space Shuttle
Program with advancing second generation research and technology development.

utilizes several Space Shuttle Main Engine technologies, including the
advanced turbopump design for both of the high-pressure turbopumps and
key sensors for advanced health management,” said Snoddy. “In addition,
COBRA has taken on development of the channel wall nozzle to help meet
second generation goals. Combining the lessons learned from the Shuttle
program with advancing technologies will enable us to develop an advanced
engine candidate for the second generation reusable launch vehicle.”

COBRA engine is one of two hydrogen-fueled engine designs being evaluated
as a first or second stage option for the next generation reusable launch
vehicle. Kerosene-fueled engines are also being considered for the first
stage booster. Engineers at the Marshall Center will narrow engine options
based on SLI requirements.

Space Launch Initiative is the beginning of a new era of human space
flight for NASA by furthering technologies needed to develop the next
generation launch vehicle. The Marshall Center leads the Space Launch
Initiative for NASA’s Office of Aerospace Technology.