To be economically viable, the operations cost of launch vehicles must be reduced by an order of magnitude as compared to the Space Transportation System (STS). A summary of propulsion-related operations cost drivers derived from a two-year study of Shuttle ground operations is presented. Examples are given of the inordinate time and cost of launch operations caused by propulsion systems designs that did not adequately consider impacts on prelaunching processing. Typical of these cost drivers are those caused by central hydraulic systems, storable propellants, gimballed engines, multiple propellants, He and N2 systems and purges, hard starts, high maintenance turbopumps, accessibility problems, and most significantly, the use of multiple, nonintegrated RCS, OMS, and main propulsion systems. Recovery and refurbishment of SRBs have resulted in expensive crash and salvage operations. Vehicle system designers are encouraged to be acutely aware of these cost drivers and to incorporate solutions (beginning with the design concepts) to avoid business as usual and costs as usual

Dickinson, William J.

Scholz, Arthur L.

English

NASA Technical Reports Server

bN90-28636
OPERATIONAL COST DRIVERS
Arthur L. Scholz
Boeing Aerospace
Kennedy Space Center, Florida 32899
and
William J. Dickinson
National Aeronautics and Space Administration
Kennedy Space Center, Florida 32899
ABSTRACT
To be economically viable, the operations cost of new launch vehicles must be reduced by an
order-of-magnitude as compared to STS.
This paper presents a summary of propulsion-related operations cost drivers derived from a
two-year study of Shuttle Ground Operations.
Examples are given of the inordinate time and cost of launch operations caused by propulsion
system designs that did not adequately consider impacts on prelaunch processing.
Typical of these cost drivers are those caused by central hydraulic systems, storable propellants,
gimballed engines, multiple propellants, He and N2 systems and purges, hard starts, high
maintenance turbopumps, accessibility problems, and most significantly, the use of multiple,
non-integrated RCS, OMS, and main propulsion systems. Recovery and refurbishment of SRB's
have resulted in expensive "crash and salvage" operations.
Vehicle system designers are encouraged to be acutely aware of these cost drivers and to
incorporate solutions -- beginning with the design concepts -- to avoid "business as usual" and
"costs as usual".
DISCUSSION
OPERATIONAL COST DRIVERS
For several decades, the Free World launch vehicles have been designed for _, with
very little attention given to considerations for _UDDOrtability and/or maintainability. As a result,
recurring cost of operations over the lite of a program has been an inordinately large contibutor to
Life Cycle Costs (LCC) - see Figure 1.
414
https://ntrs.nasa.gov/search.jsp?R=19900019320 2020-03-19T21:40:41+00:00Z
Life Cycle Costs
Figure I
&
DEVELOPMENT •
OPERATIONS •"
73%
MANUFACTURING
i R & D
MANUFACTURING
OPERATIONS
* 1.65 B$ (1965) escalated using NASA Headquarters factor of 4.199 for 1965 - 1985
** 2189.4 M$ (1985) - Data supplied by NASA to the Congressional Budget Office
Extrapolation of current operational costs (using actuals from the 8 FY85 Space Shuttle Program
launches) indicates that total Operations Costs exceeded 73% of the LCC, whereas Design and
Manufacturing were approximately 27%. This exorbitant Operations cost drives the LCC for one
100-flight Orbiter to $33.9 billion (in '85 dollars). Our best performance for the fleet of four orbiters
to date is the 8 launches in FY 85. The cost per pound to LEO exceeded $5,000! Obviously, in
future worldwide price competition, the "business as usual" approach for our Space Program will be
suicidal and must be changed.
Figure 2 describes the elements that contribute to LCC, and here we see that the process starts
with development of the Request for Proposal (RFP). Traditionally, the RFP is overburdened with
minute specifications. Many of these are necessary -- but are they looked at in light of what costs
they impose on the program vs the _ they provide? The RFP usually describes, in great
detail, "how to do it"; whereas the RFP should be primarily devoted to a generic description of the
product. Between the RFP and the delivered product, there are many contributors to Operations
costs. This discussion will address various "engine system" contributions to those operational
COSTS.
Fortunately, opportunity exists today to significantly improve the process of considering system
supportability requirements while designing a system that meets performance criteria. To make the
most of these opportunities requires two major changes in our way of doing business:
(1) Change the "mind set" of all of us in the space program to make (or accept) compromises
in performance if they contribute to a reduction in LCC.
(2) Provide more effort (dollars) upfront in the early design phase to provide for operational
efficiencies -- suoDortable and maintainable, robust systems.
415
Cost Contributors
Figure 2
MANAGEMENT
1
I CONTRACTOR
MANAGEMENT
eMkJOR IMPACT FACTORS | / Operations
• _O..SrRA_ON_ I _ Costs
/ _ \//(B OTHER IMPACT FACTORS PROCESSING
• C4.16"TOMER/U_ER REOMI'S / , TIME I _ !/'_'II
/ I • _o_co_s / ; _o I • ____ .... B
/ I "_°_""_ ) C°ST I I co. I
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-I _'_ *OTNER¢OST,.CTO.I. .I =c I
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CONTRACT ADMINISTRATION
RESEARCHDD T • E and TECHNOLOGY I LIFEcosTsCYCLE 1
PRODUCTION
As noted earlier, operations costs constitute 73% of LCC, (see Figure 3).
The original goal for shuttle turnaround was 160 hours. However, it soon became apparent that 160
hours was not achievable with the hardware designed and built within Congressional budget and
Management schedule constraints. Prior to 51-L, the goal of 680 hours had been established by
KSC as the "shortest processing time that KSC could achieve". While this was much greater than the
original "spec value", it was a justifiable goal considering the best composite processing time
achieved (1040 hours) consisted of 624 hours in the OPF by STS 8, 96 hours in the VAB by 41-C,
and 320 hours on the Pad by 51-G! This "best composite" considers the 25 vehicle
processing/launch operations of the Shuttle Program to date.
Due to the very significant changes as a result of 51-L, processing time at the end of the second
operational year (in the 1990-93 time period) is projected to be1992 hours for each of the four Shuttle
vehicles. Subsequently, the flow is projected to decrease to 1704 hours after the end of the fourth
operational year and is then expected to level off at that figure. Obviously, the Shuttle, not designed
for supportability and maintainability, will require a very significant amount of additional processing
activities tor the forseeable future.
416
Shuttle Ground Operations Processing
Life Cycle Costs (Pre / Post 51-L)
Figure 3
P_OCTE0 KOW }
IECO_ D
JU_*I**O /
SHUTTLE
PROCESSING TIME
COMPARISONS
1040 HWS
_ST COv_sn_
7--
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i _
I*I-L TOTAL
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OF POOR QUALITY
417
What can be done? Each of the design disciplines, including propulsion, can develop many cost
effective solutions which will contribute to the required reduction in LCC.
The following are some criteria for the propulsion system (engines, propellants, propellant supply,
tankage, pressurization, TVC, etc.) that can provide a significant reduction to the propulsion
contribution to operational costs of a Program. The basic objective is to _, _I_DJJIY.,and/or
eliminate functions or components. While a system may be very complex internally, the interlaces that
it presents for launch servicing and support should be as simple as possible. The less care, handling,
and support required at the launch site, the smaller the number of support people, equipment (GSE),
and/or facilities will be required. Only in this fashion can over-all launch costs be reduced. Not just the
vehicle must be simplified, the total infrastructure, and the requirements for vehicle processing
operation, must be evaluated and minimized as well.
SIMPLIFIED LAUNCH SYSTEM OPERATIONAL CRITERIA
Propulsion
INTEGRATED PROPULSION SYSTEM
Simplified robust propulsion system
• Fully throttleable engines (multi-phase)
• Soft engine start
• TVC by delta thrust and/or RCS / or aero
• One oxidizer / one fuel
ELIMINATE
O Separate OMS and RCS
O High maintenance turbopumps
O Hydraulics
O Hypergols
O GNo/He on-board purges
O GNU/He pressure systems
O Gimballed engines
O Extensive recovery &
refurbishment
Selected topics from the above listwill be addressed in the following discussions.
418
Simplified Robust Propulsion System
Operations Solution:
Simplified, integrated, robust propulsion system that, using the same oxidizer and
fuel, provides the essential elements of:
Main Propulsion
Orbit Insertion / deorbit
Attitude / Rendezvous Control
Rationale:
Current propulsion systems started with an engine design,
vehicle built around it.
with the MPS and
There is a necessity to simplify and integrate all propulsion systems to
minimize the ground operations and maintenance.
One Oxidizer / One Fuel
Operations Solution:
Design vehicles using only one oxidizer and one fuel; simplifying propellant
procurement, transport, storage, pumping, safety equipment and procedures, and
headcount.
Rationale:
Each individual propellant ground system requires expensive, hazardous facilities /
GSE, and its own little army of engineers, technicians, and safety.
STS has five propellant components, each of which require separate procurement,
transport, storage, pumping, GSE, safety, operational procedures, engineers,
technicians, etc.
Eliminate SeDarate OMS and RCS
Operations Solution:
Delete OMS and RCS as separate systems from MPS.
Rationale:
If MPS can be utilized as the hot gas source for OMS and RCS, it may significantly
lighten vehicle and will simplify ground support operations.
419
Eliminate Hiqh-Malntenance Turbo DUm_DS
Operations Solution:
The ideal solution is to _ high maintenance turbopumps. If turbopumps
remain in the system, they must be made more robust to reduce refurbishment and
maintenance requirements for recoverable stages.
Rationale:
Turbopumps are costly to develop and manufacture, heavy, run at very high RPM
and pressures, and are cavitation-sensitive.
Rocket engine cost, refurbishment frequency, refurbishment cost, and test &
checkout time are largely driven by turbopump sensitivity.
Pressure-fed engines with plug nozzles are a viable prospect as specific impulse is
relatively insensitive to chamber pressure p.P,j..,_. Chamber pressures on the order
of 200 psia should be investigated to lighten the tank structure and pressurization
system. Multiple clustered stages may be necessary to achieve the required
base/nozzle exit area.
No Hvdraulics
Operations Solution:
Provide high thrust actuators for vehicle systems using some system other than
hydraulic.
Rationale:
Hydraulic systems are heavy, complex, and plagued with O&M and GSE activities.
They require extensive facility hydraulic systems to provide a source of hydraulic
power for ground checkout of flight systems, and a separate little army of
engineer-specialists, technicians, etc.
No HyDerqols
Operations Solution:
Avoid use of hypergols for launch, orbital propulsion, or APU systems.
Rationale:
A very significant quantity of non-productive manhours occurs during each flow for
the "area clear" required during hazardous "opening', entry, or operation of orbiter
OMS and RCS systems. There is a snowballing effect in facilities and O&M
requirements for special ventilation, scrubbers and a multitude of safety equipment,
including a small army specially trained to do their job in SCAPE (self-contained
atmospheric protective ensemble) suits. Further, a pound of hypergol costs about
$8, whereas, a LOX/H 2 mix costs less than $0.22/Ib; a LOX/CH 4 mix costs less
than $0.15/Ib; and a LOX/C3H 8 costs less than $0.08/Ib.
420
NO GN2/HQ On-board Puraes
Operations Solution:
Delete launch vehicle on-board GN 2 and He purge systems.
Rationale:
Subject systems add weight to vehicle and the associated electro / mechanical /
pneumatic subsystems require special small O&M army and much time for ground
processing and launch.
Elimination of GN2 and HE storage bottles, supply valves, manifolds, plumbing, and
multiple test and checkout, will significantly lighten the vehicle, and simplify and
speed-up ground support operations.
NO Gimballed Enaines
Operations Solution:
Devise thrust vector or vehicle attitude control systems which eliminate need for
gimballed engines and associated hydraulics, seals, pivots, bellows, etc.
Rationale:
Gimballed systems are expensive, heavy, and add a severe burden of O&M, and test
and checkout to ground support operations.
CONCLUSIONS
A direct frontal attack on Life Cycle Cost reduction is of prime importance to realize the potential of any
conceptual future launch system.
The propulsion community is laced with a major challenge in reducing Life Cycle Costs. As engineers
and managers, we are prone to look for the "elegant solution". For instance, a turbopump designer is
always looking for that additional few feet of head rise while reducing the weight.
It will require a major change in "mind set" by everyone to back-off on performance requirements,
thereby seeking the goal of significantly reduced ground support operations. Compromising with the
"elegant solution" holds the promise of acquiring a launch system that can do the required job, is
relatively cheap to operate, requires very little inspection / test, and provides a robust long useful life.
If we are to be successful in the future, the battle cry must be :
DESIGN THE SUPPORT
not
Support the Design H
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