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Enhanced Reliability Features of the RL10E 1.pdf

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C 1998 International

Acre Asrronautica Vol. 41, Nos 4 IO. pp. 197-207. 1997
Published by Elsewcr Scirnce Ltd

PII: SOO94-5765(98)00077-O

Printed tn Great Britain
Sl9.00 + 0.00

W. M. Van Lerberghe’, J. L. Emdee’, and R. R. Faust’
The Aerospace Corporation
El Segundo, CA


rocket engine has been partially

developed for the United States Air Force during the
Atlas Reliability Enhancement Program. This engine is
a 22,300 lbf thrust liquid hydrogen, liquid oxygen,
derivative of the RLlOA4- 1, and incorporates an
improved ignition system and new electromechanically
actuated (EMA)
valves controlled by an engine
mounted Digital Electronic Rocket Engine Controller.

15,000 lbf for the RLIOA-3
to 22,300 Ibf for the
The RLlOE-1 engine (Figure 1) is one tf
the latest RLlO derivatives and was partially developed
during the Atlas Reliability Enhancement Program
(AREP) for the United States Air Force (USAF).

electronic control system operates
the engine with only six valves (compared to the twelve
on the




boost phase engine

cooldown capability (to avoid cryogenic temperatures at
liftoff), and allows implementation of an improved torch
ignition system with redundant, modem electronics.
Other potential reliability improvements include active
engine health monitoring, derated thrust operation,
“sot?” transients, and improved minimum residual
shutdown capability.
Although development of the RLIOE-I

was not

completed, the engine development tests were highly
successful in demonstrating engine operation with the
full authority. digital electronic control system and
fewer valves. Many of the enhanced reliability features
have been demonstrated and are directly applicable to
other versions of the RL IO engines. Potential “hybrid”
engine conftgurations offer a lower weight and less
costly engine. while retaining much of the reliability
improvements and other benefits of the RL 1OE- I.

0 1998 International Astronautical Federation.
Published by Elsevier Science Ltd

RL IO rocket engines, manufactured by Pratt &
Whitney (P&W),
have been flying since the early
1960’s. These engines bum liquid hydrogen and liquid
oxygen (LOX). Engine thrust has been uprated from

aSenior Member of the Technical Staff.
’ Section Manager. Propulsion Dept.
’ RLIO Cons&ant

Propulsion Dcpt

to The Aerospace Corporation


Figure I: RLIOE-1 Engine (XR602).

The AREP program began in 1994 as a vehicle
reliability upgrade program for the Lockheed Martin
Astronautics (LMA)
Atlas Centaur vehicle’. The
program goal was to decrease the engine failure rate by a
relative 71% of the nominal failure rate, without
decreasing vehicle performance, such that vehicle would
experience a delta reliability increase of one and a half
percentage points (A = +1.5%)
from the baseline
demonstrated vehicle reliability of 92.7%. Major amas
selected for engine improvement included the ignition
system, the control system, and the chilldown system.