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AOO-36884

AIAA 2000-3738

REUSABLE EXPENDABLE LAUNCHERCOST ANALYSISPascal PempieONESLauncher DirectorateEvry, France

and

Hilda VerninLIGERON SASaint-Aubin, France

f

36 American Institute of Aeronautics and Astronautics17-19 July, 2000

Huntsville, Alabama

Kor permission to copy or to repubUsh, contact the American Institute of Aeronautics and Astronautics*"'" Alexander Bell Drive, Suite 500, Reston, VA, 20191-4344.

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AIAA 00-3738

REUSABLE EXPENDABLE LAUNCHER COST ANALYSIS

Pascal PEMPIEC.N.E.S. Launcher Directorate

Rond Point de 1'Espace F-91023 EVRY Cedex

Hilda VERMINLIGERON SA

Les Algorithmes - Bailment Euclide F-91194 SAINT AUBIN Cedex

Abstract

In the next future the main driver to catchcommercial satellite market will be the launchoperations cost reduction.

We may also expect that the launch operations costreduction will induce a growth of the spaceapplications market.

The cost of $ 10.000 Ib is often addressed to meetthis target, and one of the main issue to costreduction is the reusability. According US literaturesurvey RLV reusable launcher vehicle could reducecost by a factor of 10 and catch as soon as year2010 a significant part of the market.

To analyse economy trends between expendableand reusable launcher a simple cost model has beenelaborated. This cost model doesn't give finalstatement but offers matter of judgement dealingwith the weight of each cost parameter.

This cost simulation is regarding the mainfollowing inputs : mission (LEO or GTO), over costof the reusable launcher compared to theexpendable one, cost of "control after flight",overhaul ground operation for vehicle retrieval,yearly mission rate, total life of fleet and reliability.

Copyright © 2000 by the Centre National d'EtudesSpatiales. Published by the American Institute ofAeronautics and Astronautics, Inc. with permission.

Introduction

Reusable versus expendable is a trade study that isinevitable, however, reusability is often presentedas a panacea, according the simplest meaninglessthat a reusable launcher is just like an expendablelaunch vehicle except it is used over and over.

This is not so simple and this debate (which is notstill yet closed !) has given origin of twodevelopment lines in USA. The first one ref. [1]managed by NASA is very aggressive since thegoal is to decrease the cost to deliver payload tolow earth orbit from $ 10.000 per pound to $ 1.000per pound. For that a focused technology programwas initiated as X-33. The second one ref. [2]managed by DOD is related to Evolved ExpendableLaunch Vehicle and requires a reduction of 25% to50% for launch system cost.

Europe, so as not to be outdone, is managing byESA/CNES a new program FLTP (FutureLaunchers Technologies Programmes) ref. [3]dedicated to the reusability topic.

On the other hand CNES via ARIANE 2010program is focussing on drastic reduction ARIANE5 cost of about 40% ref. [4].

The RLV concept has to success two challenges thefirst one is of technology feature, the second one isof economic matter.

To be able to judge, to give arguments and drawconclusions a parametric cost model seems anecessity.

Existing life cost model review

The debate about cost of reusability is currentlyopen and it is the topic of many papers : ref. [5]

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related to liquid reusable rocket, ref. [6] whichpresents many qualitative remarks about theparadox of reusability, ref. [7] concludes to theadvantage of a low cost Expendable Launcher, theconclusion of ref. [8] is that the reusable systemmust be used at a rate that is two to three timeshigher than the current flight rate. The current moreoptimistic market prevision is not unfortunately inaccordance with this conclusion. Ref. [9] answersto the question related to the optimum vehicle sizein terms of LEO payload capability for a RLV ; ref.[10] compares life cost of thirteen reusable launcherconcepts ; ref. [11] compares Expendable toReusable vehicles.

General Considerations

Two main issues are to be addressed to clarify thedebate and to avoid misunderstanding.

The first one :

What is a Reusable Vehicle ?

May be simple question but it is important to have aclear answer!

To avoid over cost due to dismantling and toconfuse "Reusable" with "Repairable" or "Rotable",clear specifications are to be issued. Ref. [12],related to the future European reusable launcher,specifies that, after landing, the control to return tofly must be performed within one day, and the nextmission can be done after one week. In case of"finding" any anomaly, the maximum delay toreturn to fly must be three weeks.

The second one:

Reusable Vehicle for which Mission ?

The design and the relevant technology, and as aconsequence, the cost are very tighten dependantmission.

So two kinds of mission must be considered:

- The first one of low energy, LEO is reachable by"simple" TSTO launcher winged like the Shuttleand many "X" vehicles or by conventionaldesigned launcher like Kistler. We may observethat almost all the RLV are designed for LEOorbits.

- The second one, for high energy GTO requiresmore heavy launcher, 3 stages (or 2 stages withbooster) and the recovery of the last stage isquestionable.

The associated question to mission is : what is thecommercial market dedicated to each one ?

The GTO market is quite well known and quitewell predictable, about 20 to 25 satellites by year.

The LEO market except the one dedicated to ISSservicing (which is not "yet" commercial !) islinked to telecommunication satellites andaccording "Iridium" collapse the market is veryunpredictable. A great dose of optimism is neededto promote a RLV development for this orbit(except for demonstration purpose).

Cost parameter lists

For a common set of input as :

. yearly mission rate (M)

. program life (A)

The following parameters are to be considered to beable to compare the life cost of an expendablelauncher fleet versus RLV :

. number of Vehicles and Spare (Zv)

. cost of the first item for expendable (CPU), learning curve factor. over cost due to reusability (a). vehicle part to be reusable versus

expendable part (8). cost related to overhaul maintenance and

retrieval operations for RLV (P). reliability : vehicle loss probability

Obviously the value of each parameter is not fixed,and quite cloudy and its scatter may be quite large ;the cost model must be able to test the conclusionrobustness versus parameter ranges.

Cost parameter Evaluations

- Yearly mission rate (M)

According ref. [12] a figure of 20 flights by yearwith a minimum of 10 and a maximum of 40 hasto be regarded.

The mean current flight rate of ARIANE is 10 byyear.

Venturstar would support 16 flights by year [13].

- Program life (A)

A program life of about 10 years seems a goodhypothesis. We may consider that after 10 years

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life the progress in the launcher technology fieldwill make the fleet obsolete.

In any case it will be advisable to foresee financialprovision for vehicle retrofit.

So, considering a fleet of about five vehicles, theindividual design life will be about 100 flights.

This figure is to be compared to Space Lunarvehicle life (500 to 2000 missions) Kistler (100flights) early Shuttle requirements (10 years/100missions) ref. [15] and Japan RLV program [16].

By comparison the Shuttle Fleet includes 4vehicles, it is planned two Venturstar and it isforeseen 3 set orbiters and boosters for X Van [22].

Over Cost due to Reusability (a)

With the reusable vehicle needs to be retrievedadditional hardware like parachute and airbag(Kistler) or a set of wings, auxiliary propulsion,landing gear (like Shuttle) and extra propellants.

The vehicle, to be able to support the high thermicloads during the re-entry, has to be protected bycomplex TPS (Thermal Protection System).

All these complementary functions are bringingpenalty in structural mass and as a consequence, fora fixed payload mass, figures are increasingsignificantly the GLOW (Gross Lift-Off Weight)about two times.

All these considerations lead to consider aminimum cost factor of 2,and an average one of 3.

As example it may be indicated that for Ariane 5solid propellant booster, the over cost includingparachute, operations to recover and tow it by arented ship represents 6 per cent of the purchasecost. This data may be considered as the lowestfigure.

It can be also find in the literature [21] that the costof a reusable winged vehicles is eight time the costof an expendable vehicle for same GLOW.(CPU = cc.GLOW °'485; a = 40 for winged vehiclesand a = 4,8 for ballistic expandable stages).

Maintenance and Overhaul Cost ((3)

We must recognise that we have no backgroundrelated to this topic and the overhaul cost is the

main unknown. It is however the key factor whichwill determine the economic benefit for RLV.

We consider as for aircraft overhaul ([19] and [20])a fixed cost part (indirect cost) and a cost partdedicated to mission rate (direct cost) and weconsider that the overhaul will increase with thefleet age.

The operations which are dedicated to retrieve thevehicle and to bring it again to its "Launch pad"generate also over cost.

• Some parts of the vehicle, like the engines, willnot be able to meet all the program duration, soperiodic replacing will to be done and theconsequences on cost are to be drawn.

As example, it may be mentioned that a total of 34main engines had flown during the first 75 spaceShuttle missions and the maximum number ofmissions was 17 for one engine and the mean valuewas about 5 missions/engine. So 20 missions byengine may be considered.

• The ageing of the feet will increase themaintenance cost. According Aircraft lessonlearned it may be considered that after 2/3 of thelive the maintenance cost increase according tothe following factor:

oZnr'aa.

Zmissionag.

Reusable Part Vehicle

• For LEO mission it may be assumed that all thevehicle is able to be recovered and reusable.

• For launchers, which are going towards GTOmission, it may be considered that this kind oflaunchers is made of three main parts.

Except the upper stage (kick stage), whichrecovery is questionable and seems a tough job,the strap on booster and/or the central core maybe, from technical point of view, reusable.

Currently Shuttle Solid Booster is reused but after aprobably costly overhaul. Some Ariane 5 boostersare recovered to be checked only. However the useof liquid fly back booster is the first step towardsreusability as presented ref. [17] for Shuttle and ref.[18] for Ariane

Figure 1 shows simplified cost break down.Roughly the expendable launcher cost (exceptoperations) may be shared as :

61 = 0,45 for booster82 = 0,33 for central core

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53 = 0,22 for upper stage considered asexpendable ^- expendable

Fig.1: Launcher Hardware Cost

RLV Configuration Strategy

• For LEO three configurations are to beconsidered for a TSTO vehicle.

a) the first and second stage reusables (FullyReusable)

b) the first stage reusable and the upper stageexpendable (Reus. Exp.),

c) the upper stage is reusable and it is assistedfor take off by expendable "low cost" solidboosters.

• For GTO these configurations are to becompleted by a third expendable kick stage.

Figure 2 shows the current RLV configuration, thedate is mainly taken from [23] and [24].

Figure 2 - RVL Configuration :

ASTROLINERKISTLERPATHFINDERROTON C9SPACE ACCESSX V A NSTAR BOOSTERVENTURESTAR

Staging

R.R.E.R.R.R.E.RR.E.R.R.R.E.R.

Mission

LEOLEO

TEOLEOLEOLEOLEOLEO

PayloadMassT

4,5[12,33200,56 to 1811

GLOWT

N.A.37843 (t.b.c.)181

76

992

Economic Relations

The total cost, without investment return, may beestimated by these following basic relations.

Expendable

The total amount has to consider only the purchasecosts weighted by the learning factor.

R.L.V. (Reusable^- Expendable Configuration)

The total cost is the sum of the Reusable Fleetpurchase price and its set of spare engines cost, ofthe purchase values for the Z missions LauncherExpendable stages and the maintenance cost.

c,.

eng

endable

x=l2/3/H/.V.V/0/7

Z=l3/3

.CPU2 / 3

with :

CPU = Cost of the first expendable vehicleb Learning coefficient§1 1st stage relative cost versus vehicle total

costcteng Relative engine costarew Over cost due to reusability (Reus.

Coeff.)j3maint. Maintenance cost coefficient (Maint.

Coeff.(3 ag. Maintenance ageing coefficient

Econom ic Anajysjs

For all these three TSTO, RLV vehicleconfigurations an economic simulation has beenperformed using the following data set:

CPU

Program lifeMission rateLearning factora over cost (Reus. Coeff.)a engine

Pmaint. (Maint. Coeff.)P ageing

§.62

100 (cost of the firstexpendable unit)

10 years10 by year-0,1522/3/40,2 (Cost part of the

Engine)

0,05/0,1/0,21,010,40,6

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RLV fleet vehicles:Number of engines:

520

The figure 3 compares as example the cumulatedcost versus time for Fully Expendable, FullyReusable and First Stage Reusable and SecondStage Expendable.

Fig.3: Fully Expendable / Fully Reusable / Reusable ; Expendable{ Maint. Coeff. = 0.1 Reus. Coeff. = 3 10 mlssions/Y )

' Fully expendable " Reusabla/Expendable I

In some papers RLV is presented profitable in caseof high yearly mission cadence. The figure 5represents trend in contradiction. A possibleexplanation is that a high mission rate needs morevehicles and higher investment.

Flg.5: Yearly Mission rate influei

Conclusion

The cross over, i.e. the date when the Reusableconcept should draw profit versus expendable isabout 6 years and partially reusable, configurationdoes not seem to bring important effect.

An important point to be emphasised is thatReusable Fleet needs a high investment at thebeginning.

The figure 4 presents the influence of the main twinparameters (Purchase Overcost due to theReusability and Maintenance Cost) and defines thedomain where RLV could draw profit.

Figure 4

NO PROFIT

PROFIT

|— ' Fully Reus- —• Reus.Expend I

It is not the topic of this paper to draw finalconclusion about RLV or Expendable Vehicleprofit, however profit seems possible only if theReusable Vehicle Cost and Maintenance Cost aremastered tightly.

It must be emphasised that the RLV needs highinvestment related to the Fleet, and the profitabilitycompared to other activity, could not easily callmoney from private investors. (It must be observedthat this present economic analysis doesnlt take into account return on investment).

The risk of a lower mission cadence or aninterruption, due to, for example, a mission mishaphas to be included in the RLV Business Plansimulation.

LEO market, which is the dedicated market forRLV TSTO, has to be confirmed and anchored.

In any case RLV represents a fantastictechnological challenge !

References

[1] R.W. PC-WELL, S.A. COOKThe Road from the NASA, Access-to-SpaceStudy to Reusable Launch Vehicle - IAF 98-V-4-02

[2] R.W. Me KINNEY and alEvolved Expendable Launch Vehicle : TheCompetitive New Launcher - IAF 98.1.1.03

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[3] Ch. BONNAL, M. CAPORICCIFuture Reusable Launch Vehicles in Europe :the FLTP - IAF 99-V.409

[4] Ch. BONNALFuture Launch Vehicles in Europe -Symposium on Reusable Rocket Vehicles -08/05/2000 - Sendai, Japan

[5] J. HAMAKER and G. DOODExpandable US Reusable Propulsion SystemsCost Sensitivity - AIAA 89-2402

[6] E.L. KEITHThe Cost of Reusability - AIAA 95-3090

[7] Z. HUANGCost Effectiveness Comparison BetweenExpendable and Reusable Vehicles - IAF1.1.04.1998

[8] A. PALENEconomic Comparison of New Reusable andExpendable Launch Systems AIAA 94-4547

[9] D.E. KOELLEThe Cost Optimal Size of Future ReusableLaunch Vehicles - 99 IAF 1.1.05

[10] W. BERRYLife cycle Cost Comparison of ReusableLaunch Systems - AIAA 95-1.1.02

[11] BobPARKINSONThe Economics of an RLV - Le Bourget 99

[12] C. BONNALFLTP - Cahier des Charges Fonctionnelles duFutur Lanceur Europeen Reutilisable -FLTP CF 1-1 CNES

[13] R.F. JOHNSON, P.L. SMITHFuture Space Lift Projections - Space policy14 (1998)

[14] R. WANGThe K.I Reusable Vehicle. Meeting theDemand for LEO Satellite Delivery Services

[15] R.E. FIELDPropulsion requirements for Space Shuttle -AIAA 71-657

[16] J. KOUCHIYAMA and alDevelopment Plan and Status of the RLVSOperated in 2010's

[17] T.J. HEALY Jr. - Shuttle liquid fly backbooster configuration options - 1998 JANNAF

[18] E.A. STANISZEWSKI - Liquid Fly BackBooster for Post Ariane 5 - IAF 98.V308

[19] J.P. GENOTTIN - Maintenance Cost Analysis- AIAA Airbus Activities and Results - FASTNumber 25

[20] J.P. PQUBEAU - Air Bus Industrie -Maintenance Economic Analysis - PrivateCommunication

[21] D.E. KOELLE"The Transcost Model for Launch VehicleDevelopment, Production and Operations CostEstimation - IAA Symp. on Space Syst. CostMeth.-May 1990

[22] L. CORMIERSmall TSTO RLVs : Market-BuildingStepping Stores to SSTO RLVs - AIAA-99-2620

[23] F.A.A./AST2000 Reusable Launch Vehicle Programs andConcepts

[24] D.I. WADECommercial Development of Satellite LaunchVehicles - I.E.E. 1999

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