automated transfer vehicle (atv) - esa

Figure 1. ATV approaches the ISS

Automated Transfer Vehicle (ATV)Structural and Thermal Model Testing atESTEC

P. Amadieu, G. Beckwith, B. DoreATV Project, ESA Directorate of Manned Spaceflight and Microgravity, Les Mureaux, France

J.P. Bouchery EADS Launch Vehicles, Space Programme Directorate, ATV Programme, Les Mureaux, France

V. Pery EADS Launch Vehicles, Systems Design and Tests Directorate, Systems Tests Department, Les Mureaux, France

ATV descriptionATV capabilitiesThe Automated Transfer Vehicle (ATV) beingdeveloped by ESA is an unmanned vehicle thatcan be configured to provide the InternationalSpace Station (ISS) with up to 5500 kg of drysupplies (e.g. hardware, food and clothes) andliquid and gas supplies (up to 840 kg of water;up to 100 kg of gases (air, nitrogen, oxygen); upto 860 kg of refuelling propellant). ATV canprovide propulsion support to the ISS by usingup to 4700 kg of propellant. The total netpayload is estimated to be at least 7500 kg.Finally, ATV can also remove up to 6500 kg ofwaste from the Station.

– the Equipped Propulsion Bay (EPB), whichaccommodates most of the Propulsion andReboost Subsystem (some thrusters are alsolocated on the forward part of the ICC);

– the Equipped Avionics Bay (EAB), whichaccommodates most of the avionics equip-ment (some avionics items such as rendez-vous sensors are located in the ICC and EPB);

– the Solar Generation System (SGS), whichincludes four 4-panel deployable solar wings,each with its own drive mechanism.

The ICC accommodates all cargo apart fromthe reboost propellant (carried in thespacecraft) and consists of:– the Equipped Pressurised Module (EPM),

which accommodates dry cargo in dedicatedpayload racks. ISS waste is carried for thedestructive reentry part of the ATV mission;

– the Equipped External Bay (EEB), which is anunpressurised assembly to house water, gasand refuelling propellant tanks;

– the Russian Docking System (RDS), whichprovides capture and release for dockingwith and departure from the ISS. SeveralRDS models, including for the first ATV, arebeing provided by Russia as a barter for theEuropean Data Management System that iscurrently operating in the Station’s ZvezdaRussian Service Module.

The ICC and SC are protected by the externalMeteoroid and Debris Protection System(MDPS) shield.

ATV development logic and main systemmodelsThe ATV flight segment assembly, integration

The ATV Structural and Thermal Model (STM) test campaign began atthe ESTEC Test Centre in October 2001. ATV’s capabilities, mission,configuration and development logic are outlined. The STM TestCampaign and test objectives are then detailed. Some specialrequirements imposed by ATV’s size are described. The main testresults and lessons learned are summarised.

automated transfer vehicle

At least eight ATV flights to the ISS are plannedas part of the European contribution tosupporting ISS operations (Fig. 1).

ATV configurationThe ATV vehicle is composed of two elements(Fig. 2): the spacecraft (SC; including solararray) and Integrated Cargo Carrier (ICC).

The ATV spacecraft comprises:– the Separation and Distancing Module (SDM),

which provides the mechanical interface withAriane-5 and ATV’s separation and distancingfrom the launcher;

95

r bulletin 111 — august 2002

96

Figure 2. ATV subassemblies and dimensions

ATTITUDE CONTROL THRUSTERS

MDPS CC

Ø 4482 MAXI MDPS WITHOUT MLI

MAIN THRUSTERS

PROPELLANT TANKS

SEPARATION ANDDISTANCING MODULE (SDM)

EQUIPPEDPROPULSION BAY (EPB)

EQUIPPED AVIONICS BAY (EAB)

EQUIPPED EXT. BAY (EEB)

EQUIPPEDPRESSURIZEDMODULE (EPM)

RUSSIAN DOCKINGSYSTEM (RDS)

GAS, WATER AND RFS

AVIONICS EQUIPMENTCHAINS (AEC)

RADIATORS EAB

MDPS EPB

SEPARATION PLANE

SOLAR GENERATIONSYSTEM (SGS)

ATTITUDE CONTROL ANDBRAKING THRUSTERSSPACECRAFT

SUBASSEMBLY

INTEGRATEDCARGO CARRIER

1077

3

4916

3330

2000

Figure 3. STM ESTEC testcampaign sequence

adequacy for ATV to save on delta-qualificationor redesign. Another goal of the vibration tests(acoustic, sine) is to characterise the vibrationenvironment experienced by ATV payloads inthe payload racks.

The STM campaign began at the end ofOctober 2001. Figure 3 shows the testsequence.

STM representativityThe SDM model consists of a flight-representative structure, with a real clampbandseparation device equipped with connectors,but no distancing spring. The rest of the SCstructure has only minor differences from theFlight Model. Its equipment mock-ups aredynamically and thermally representative; thestiffness at bracket interfaces is representativeof the Flight Model, and there is 80% of theEPB harness and plumbing. Propulsionsubsystem tanks are fillable structural mock-ups. The Thermal Control System is fully flight-representative. One solar wing is mechanicallyflight representative; the other three aresimulated by single-panel mock-ups (identicalmass and area as folded wings).

The ICC STM is dynamically representative ofthe Flight Model. The EPM (replaced by aspecial mock-up for thermal testing) structureincludes a cylindrical shell and aft and forwardconical parts. The EEB shows minordifferences with respect to Flight Models.Racks are flight-standard. The RussianDocking System (RDS) is a mechanically andthermally representative mock-up. The ICCforward cone features a mechanical mock-up

and verification during Phase-C/D uses threesystem-level models: STM, Electrical TestModel (ETM) and Proto-Flight Model (PFM).

The STM is being used for environmental testsin the ESTEC Test Centre. After these tests, theSC will be subjected to static tests atContraves (CH). The ICC external bay will besubjected to further dynamic and static tests(together with a flight-standard pressurisedmodule). The STM pressurised module will berefurbished at Alenia (I) and eventually used forcrew training at the European Astronaut Centrein Cologne (D).

The ETM is being used for functionalqualification testing of the ATV and for a first setof vehicle/ground segment compatibility tests.After initial integration and electrical testing ofthe EAB ETM at Astrium SAS (F), the full ATVETM (including the ETM models of the avionicequipment in the ICC and EPB) will beintegrated at EADS Launch Vehicles.

The PFM, now named ‘Jules Verne’, will besubjected to the following environmental andfunctional tests:– acoustic– electromagnetic compatibility– solar wing deployment– clampband release– thermal test (EAB level)– final set of vehicle/ground segment

compatibility tests– complementary electrical and functional

qualification tests– functional acceptance.

The ATV Flight Segment prime contractor forPhases-C/D (development, manufacture,integration of first vehicle and associatedground support equipment, as well as ATVqualification) is EADS Launch Vehicles (LesMureaux, F). The main contractors responsiblefor the subsystems and/or the ATV sub-assemblies are: – Astrium GmbH (Bremen, D), propulsion and

reboost subsystem, SC integration– Alenia Spazio (Turin, I), ICC– Astrium SAS (Toulouse, F), avionics sub-

system, EAB integration– Contraves (Zurich, CH), SC structure sub-

system– Dutch Space (Leiden, NL), solar array.

Testing at ESTECThe main objective of the STM test campaign isto verify the vehicle’s mechanical and thermalbehaviour. Since many ATV components areeither derived or directly reused from previousprogrammes, the dynamic tests are ofparticular importance for confirming their


97

Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

STM Test Campaign

Acoustic Test

Modal Survey Tests

Dynamic & SDM Tests

Shock Tests

SGS Deployment Tests

Thermal Test

EMC Test

Packaging

End of campaign

25/10

17/12

15/04

06/05

03/06

17/06

12/08

21/08

10/09

Figure 4. ATV on theAcoustic Stand in LEAF

of a rendezvous sensor, on its dedicatedsupport. ICC gas tanks are structural modelswith masses representative of filled tanks.Refuelling System (RFS) kits and water tanksare fillable structural models, with dummyvalves and partial plumbing.

Acoustic testCharacterisation of the vibro-acoustic responseof ATV to the acoustic levels induced by theAriane-5 launch and flight was the majorrequirement of the acoustic test. The final goalwas to compare acoustic and random vibrationlevels to those specified for ATV’s majorcomponents and equipment. Tests wereperformed in December 2001 in the LargeEuropean Acoustic Facility (LEAF) at ESTEC.

ATV with a total mass of 15 t (low loadedconfiguration) was mated with the AcousticUncoupling Stand (AUS, Fig. 4). This adapterdynamically uncouples ATV from the ground, as well as positioning it inside LEAF’s homo-geneous acoustic field. Uncoupling wasachieved at the top of the adapter throughrubber isolator mounting pads. A dry-run testinvolving the AUS alone was performed a fewweeks before the STM test itself.

The test sequence was:– low-level run: overall level 141 dB for 66 s– intermediate-level run: overall level 143 dB

for 60 s– qualification-level run: overall level 147 dB for

120 s

– low-level run (to check sensors’ individualresponses and to assess structural integrityafter the testing): overall level 141 dB for 60 s.

Achievement of homogeneity and the specifiedtest spectrum took less than a minute for eachtest run. After the first run, microphonepositioning was optimised; they were movedfurther from the STM, outside the acoustichomogeneous field. This unusual setting wasdue to the STM’s size, which fully occupied theLEAF acoustic homogeneous field. During thequalification-level run, nitrogen aerodynamicnoise at 4 kHz in the LEAF made the targetinput level in this non-critical band impossibleto tune precisely (higher levels than requiredwere achieved).

All these tests were successfullyperformed within 4 days. Qualifica-tion random levels for equipment arein the process of being confirmed bytest-result analysis.

Modal survey The test characterised the globaldynamic behaviour of the completeATV: the main longitudinal and lateralstructural eigenmodes of the ATV,and (when uncoupled) the eigen-modes of the vehicle’s maincomponents. Eigenfrequencies andshapes, effective and generalisedmasses and damping factors of theeigenmodes were produced bymodal survey tests. These results arebeing used for updating the ATVmathematical model for ATV/Ariane-5 coupled load analysis.

The modal survey logic was basedon two test configurations withdifferent fluid and dry-cargo loadings.In reality, ATV will carry a wide rangeof payload combinations. Both

configurations had a mass of around 20 t. Thefirst used an extreme payload distributionchosen to produce maximum dynamiccoupling between SC and ICC. The secondwas closer to a probable payload distributionfor the first ATV flight, with clearly separated SCand ICC eigenmodes. The STM was interfacedwith the ground by the MechanicalInterface (MIF) test adapter. Its double conicalshape ensured that the high lateraleigenfrequency did not interfere with ATV’smain eigenmodes during the tests.

Two methods were possible for performing thetests:– local exciters in LEAF, with its seismic block

of around 2000 t of concrete. The test principle


98

Figure 5. Lateral modalsurvey test set-up with ATVon MIF

A quick longitudinal test was added in LEAFusing one local exciter hanging from a craneand mated with the ICC upper handling ring. Itspurpose was to prepare for HYDRA runs byidentifying primary longitudinal targeteigenmodes.

The transfer of STM and MIF to HYDRA finallyallowed the main longitudinal runs to begin (Fig. 6). Both configurations underwentlongitudinal modal survey tests on HYDRA and

would then be phase resonance (direct modalidentification): broad-band low-level sweeps,followed by tuned sine excitation (for identification of primary target eigenmodes),and narrow-band sweeps (for determination ofmodal parameters and non-linearities). Furthertarget eigenmode information would beavailable through broad-band sweep analysis

– the HYDRA hydraulic shaker (3-axis excitationthrough eight actuators of 630 kN; four on thevertical axis, two on each lateral axis). Theapproach would be phase separation withbroad-band low-level sweeps through sineexcitation for eigenmode identification,customised broad-band sweeps and analysisto determine modal parameters and assessnon-linearities. Use of HYDRA implies record-ing of temporal data, requiring further analysisto derive Frequency Response Functions.

The choice was driven by one HYDRA mainconstraint: lateral excitation along one axisresults in non-negligible 3-axis excitation owingto ‘cross-talk’ effects. In order to limit risks forthe success of the test, the decision was takento use local exciters for lateral excitation inLEAF, and to use HYDRA only for longitudinaltests since this allowed higher load levels,which are useful for the estimation of damping.

Following acoustic tests, the LEAF lateral teston the first configuration started in February2002. IABG provided four exciters: two of2.2 kN were placed at the SC/ICC interfacelevel and two of 7 kN were placed at the ICCupper handling ring level. The IABG dataacquisition system recorded information fromaround 580 accelerometers and 50 straingauges that measured SC/ICC and SC/adapterinterface force fluxes. Figure 5 shows the testset-up.

Since the MIF adapter was designed tointerface with the HYDRA table, its use in LEAFrequired a special metal plate, bolted andtorqued to the ground, onto which the MIF wasfixed. To ensure proper clamping of the testspecimen to LEAF’s seismic block, an epoxylayer was laid between the plate and ground.The test configuration was finally set up after afloor compliance measurement with only theMIF mated via the metal plate to the ground.

The lateral testing took 4 days, including broad-band and narrow-band sweeps, and identifiedall target eigenmodes. Raw results werecorrected with respect to ground effects(unsymmetrical stiffness at the base of the testset-up) using forces and accelerationsmeasured on the test floor and test adapter.


99

Figure 6. Longitudinal modalsurvey test set-up onHYDRA

Figures 7a-c. Achievedlevels for dynamic tests

provided satisfactory results, confirming thetest predictions.

Further lateral tests were performed onHYDRA. Owing to the complex rocking motionof the table in specific frequency bands, theindividual behaviours of ATV and the tableproved difficult to decorrelate, so it was notpossible to assess precisely the associateddamping factors. However, those runsconfirmed the eigenfrequencies of the firstbending modes.

It was considered that these tests had providedsufficient information, so the test sequence wasshortened and the second set of LEAF lateraltesting was cancelled.

Dynamic qualificationConsidering ATV’s high mass (up to 20.75 t)and ESTEC’s testing capabilities, the initial logicwas of qualification in stages: Finite ElementModel (FEM) updating after modal test,updated Ariane-5/ATV coupled-load analysis to assess dynamic qualification levels, testpredictions for the SC and ICC separately, andseparate dynamic tests for the SC and ICC.

However, given the good correlation betweenthe STM FEM predictions and the modalresults, and HYDRA’s proven capability duringmodal survey tests to apply the requireddynamic levels to the combined (ATV and MIF)mass of 24 t, the opportunity was taken tomake use of the full STM configuration (withoutSDM). Thus, the new logic consisted ofperforming iterative runs to achieve levels ashigh as possible, taking into account themaximum allowable levels for ATV’s maincomponents and critical equipment, as well as

the expected Ariane-5 dynamicenvironment. Test-result evaluation andpost-test analyses would then verifythat ATV can withstand the Ariane-5environment with adequate margins.

After analysis of the modal surveyresults and following a thorough ATVinspection, some additional sensorswere integrated into the STM. Testsalong the X- (vertical) and Y- (lateral)axes were then first performed:intermediate-level runs (around 80% offlight limit levels) to record all availablechannels, then assessment of transferfunctions for all measurement points todeduce the next run at increasedlevels.

Coupling between the shaker and thetest article resulted in artificial dampingat the eigenfrequency of the first ATVbending mode. The input levels wereadapted around this eigenfrequency toobtain the correct force at the ATVinterface. Interactions between the testarticle and the shaker table inducedcontrol difficulties, and therefore limitedthe input levels at specific frequencies.In this case, the finally applied levelswere adjusted to reach qualificationlevels on heavy items such aspropellant tanks.

These two first dynamic qualificationtests were completed successfully.

Given the test configuration symmetry, Z-axisinput levels were the same as those specifiedalong the Y-axis. Figures 7a-c show the finalapplied input levels at ATV’s base. Differencesbetween the specified and achieved levels werecaused by either notching or control effects.The qualification testing in three axes wasconsidered to be successfully completed at theend of April 2002. The final Ariane-5/ATVcoupled-load analysis aims to confirm the inputlevels used during the tests.

Thanks to HYDRA, the ATV STM is the heaviestand largest specimen ever subjected to high-


100

X axis dynamic levels

a

b

c

m/s

2m

/s2

m/s

2

Y axis dynamic levels

Z axis dynamic levels

Frequency

Frequency

Frequency

Figure 8. ATV (with SDM)modal tests on HYDRA

level sine vibration testing for an ESAprogramme.

The sine-test specifications for equipmentwere refined on the basis of the results ofthe qualification tests. In particular,qualification vibration specifications forATV’s Russian equipment, originallyqualified for launch on Russian vehicles,are in the process of being confirmed. Thiswould avoid modification of those itemswhen used on ATV.

Mechanical qualification testing will becompleted by static tests on the primarystructure and by pressure integrity tests onthe pressurised module.

ATV (including SDM) modal testThe 2 m-high SDM cylindrical adapter wasdeveloped for ATV to interface directly withAriane-5’s 3936 mm diameter. The SDMadapter includes a clampband separationsystem that was developed specially forATV’s large diameter. This adapter uses thenew ‘clamp ring separation system’technology, which offers the advantage ofgenerating low shock levels.

In order to assess the influence of the adapteron ATV’s global dynamic behaviour, it wasdecided to perform additional characterisationtests. The complete ATV launch configuration(including SDM) was vibration-tested onHYDRA in the longitudinal and lateral directions(low levels, X and Y excitations; Fig. 8). Thetests verified the compliance of ATV’s (includingSDM) first lateral eigenfrequency with Ariane-5’s requirements (i.e. this eigenfrequencyshould be high enough to avoid influencinglauncher behaviour).

Shock tests Shock tests involved a complete ATV/SDMconfiguration hoisted in the HYDRAPreparation Area (Fig. 9). The first shock test(the ‘Shogun’ test) dealt with the ATV externalshock from the jettisoning of Ariane’s fairing. Adedicated pyrotechnic device (Shogun) wasprovided by Arianespace to generate theserepresentative shock levels at the SDMinterface. This device was made of apyrotechnic linear cord charge inside aweakened aluminium structure (3936 mmdiameter). The shock wave was generated bythe expansion of the tube causing a controlledrupture of the lower flange screw section. Aspacer (a 260 mm-diameter cylinder developedfor ATV ground integration operations) providedthe interface between the SDM and Shogun,and was intended to create the proper shocklevel at SDM’s lower interface.


101

Figure 9. ATV shock testset-up in the HYDRA

preparation area

Figure 10. Solar wing underthe deployment rig

A dry-run at the end of March 2002demonstrated that Shogun produced therequired shock levels. The STM Shogun testwas successfully completed at the end of May.

The second shock test concerned theclampband release. The Shogun and spacerwere removed, and SDM was held to preventits lower half falling after release. The test usedshock sensors and two high-speed cameras(1000 frames/s). The clampband wassuccessfully released after exposure to theShogun shock.

The shock transfer functions from the bottomof the ATV to the most critical equipment weremeasured. It was verified that the shock at thebase of ICC produced negligible levels for thismodule’s equipment. The shock levels on theother equipment will be derived by post-test

analyses using these transfer functions. Themain goal of the second test was to measurethe shock levels at the most critical equipmentinterfaces. Further analysis incorporating theresults of the two tests will validate the shockspecifications for ATV’s various elements andconfirm, where necessary, the system margins.

Solar array deploymentAn associated goal was assigned to theacoustic and shock tests: the application ofthese environments to a stowed solar array inorder to verify its correct deployment. Thedeployment test took place following the end ofshock tests with the SC horizontal (and without SDM or ICC). A rig held the wing tocompensate for gravity (Fig. 10). Thedeployment was successful. The times forcutting the hold-down cables and for wing

deployment were within specifications.Deployment was therefore demonstrated afterexposure to the acoustic, shock and dynamicqualification environments.

Thermal balance testChecking and upgrading ATV’s ThermalMathematical Model, to be used for ATVqualification, will be achieved via global thermalcharacterisation in vacuum of a test specimenthermally representative of ATV underdissipative and environmental thermal loads.

The semi-active Thermal Control System (TCS)is based on Active Fluidic Cooling Units(AFCUs) containing heat pipes. The verificationof its performance required the characterisationof the AFCU heat rejection maximal capacity ina hot environment and of the AFCU maximalinsulation in a cold environment. The thermaltest also verified the thermal control algorithmsand thus the capacity of this TCS subsystem tomaintain the vehicle within required limits.Secondary objectives, such as identification ofthe heat leak sources and confirmation of theheat leak budget, and thermal characterisationof the docking system and structure underthermo-mechanical loads, were also addres-sed.

This was the final STM test at ESTEC, in theLarge Space Simulator (LSS) between the endof July and early August 2002. Severe thermalrequirements drove the ATV configurationinside LSS (Figs. 11 and 12):– keeping the heat pipes horizontal was critical

for them to work. This meant that ATV had tobe vertical inside the LSS, and thereforeheated from the side by the solar simulator

– the STM had to be illuminated by the solarbeam to simulate the hot and cold transientand steady flight phases, and thermal cycling.The 6 m-diameter beam required replacingthe EPM (pressurised, temperature-controlledmodule, behaving only as a thermal inertia)with a smaller mock-up

– the three sides not in direct view of the Sunhad to face controllable, simulated Earththermal fluxes. This was supplied via astructure in three planes (Figs. 11 and 12show two). Each plane of this EASi (EArthSimulator) consisted of 15 individually heatedpanels. The complete assembly was matedto the LSS seismic platform through a support ring

– the aft side had to face a simulated Sun anddeep space (the LSS seismic platform is uncooled). This SORSi (SOlar Rear Simulator)was equipped with heaters and liquid-nitrogencirculation for the different test-phase needs.

– the Thermal Test Stand connecting the STMand LSS platform minimised the thermal


102


103

fluxes between the two, as well as limitinginterference with the LSS walls. This wasachieved by a tubular lightweight structurewith controlled thermal properties (thermalisolation, control of interface temperatures,multi-layer insulation).

As probably one of the most complex parts ofthe STM campaign, the thermal test alsoinvolved numerous electrical lines dedicated to:– supplying 55 kW to more than 200 main lines

for the heaters that simulated equipmentpower dissipation inside the STM, and for theheaters that guaranteed the thermal environ-ment and boundary conditions for ATV ortest adaptation interfaces

– acquisition of measurements from more than800 thermocouples dedicated to measurementor control

– control of the AFCUs.

Additional activitiesSome tests and measurements, though notdirectly associated with the environmental teststhemselves but linked to operationalverification, were added during the variousphases of the STM test campaign. Indeed, theSTM integration and test operations prefigureactivities to be performed with the first FlightModel, either during its test campaign atESTEC or during the launch campaign atKourou, French Guiana.

Knowing the time and manpower required foreach activity will allow the schedule for groundprocessing at Kourou to be refined. Throughoutthe test campaign, the large size of the ATVelements and the Mechanical Ground SupportEquipment (MGSE) compared to that of theESTEC cleanrooms led to numerous move-ments within the test facility. For example, tiltingthe SC from vertical to horizontal requires aground area of about 6 x 9 m2. Figure 13 high-lights the size of the ICC container. The lessonslearned in using the MGSE will help in laying outthe integration and check-out area in the new S5building at Kourou.

The STM test campaign also involvedintegrating ATV’s major subassemblies (SC,ICC, SDM) for the first time (Fig. 14). Thisverified the interfaces between such largestructures. Some of the techniques developedfor STM will be used for Flight Model integrationand operations in Europe and Kourou. Forexample, the AUS will be reused as an ATVintegration and transfer stand.

Three operational verifications were also carriedout on the SDM:– characterising the evolution of clampband

tension during the various integration Figure 12. The ATV STM in ESTEC’s LSS before thermal-balance testing

Figure 11. Thermal testset-up preparation in LSS

– verifying the mating of the SDC (Separationand Distancing Cylinder, which is SDM’slower part) and the SES (SEparation System,which is SDM’s upper part) when ATV isfully integrated.

The alignment of some elements of ATVGuidance Navigation and Control (GNCsensors and thrusters) is critical for therobustness of the flight control algorithms.Before and after each environmental test, theposition and orientation of these elements weremeasured via videogrammetry in order toassess the impact of the applied environment.

Finally, a short electromagnetic (EM) test wasperformed using the thermal test configurationto measure the EM-shielding effectiveness ofthe EAB structure. The EM field was generatedaround the test object and specific testantennas allowed characterisation of the EMfield inside the avionics bay. The resultsshowed that the ATV structure provides therequired attenuation of external EM fields.

ConclusionThe STM test campaign proved to be veryintense. In addition to its own teams, EADSLaunch Vehicles managed and coordinatedteams from ETS (logistics, test logistics),Astrium (mechanical and fluidic operations),IABG (modal and dynamic tests), Arianespaceand Intespace (shock tests) and other ATVsubcontractors (Alenia, Contraves, EADSCASA, Dutch Space, APCO). ESA, as ATVcustomer, performed programmatic andtechnical monitoring. Numerous decisions hadto be taken ‘on the spot’, making use ofavailable materials and means. All thechallenges were successfully met thanks to theefforts and constructive ideas of these teams,and the STM test campaign is expected to be completed by mid-September 2002,2 months ahead of schedule. All involved are tobe thanked for their dedication andcommitment. This ESTEC campaign was thefirst involving ATV and all the related groundsupport. It offered a unique opportunity tocheck most of the critical mechanicaloperations that will be required for the flightoperations in Europe and Kourou. The datagathered during this test campaign pave theway for the ATV Critical Design Review in April2003 and for the PFM ‘Jules Verne’ ESTEC testcampaign and Kourou operations.

AcknowledgementsThe authors thank all their colleagues who,through their comments, contributed to thisarticle. r

Figure 14. Preparing for thefirst mechanical integration

of ATV

operations. This tension was measured beforeand after the mating of the SDM with thespacer and the SC at, respectively, its lowerand upper interfaces. Additional measurementswere performed with and without ATV’s masson it (ATV hanging from the overhead crane).The goal was to verify the possibility oftensioning the clampband before PFM fillingoperations. The mathematical model wasupdated from the results

– measuring the geometry of SDM’s lowestinterface (when mated with the rest of ATV) toverify Ariane-5/ATV integration


104

Figure 13. The ICC containeris unloaded from the Beluga

aircraft at Schiphol airport

automated transfer vehicle (atv) - esa

Documents