Figure 1. ATV approaches the ISS automated transfer vehicle Automated Transfer Vehicle (ATV) Structural and Thermal Model Testing at ESTEC P. Amadieu, G. Beckwith, B. Dore ATV 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 description – the Equipped Propulsion Bay (EPB), which ATV capabilities accommodates most of the Propulsion and The Automated Transfer Vehicle (ATV) being Reboost Subsystem (some thrusters are also developed by ESA is an unmanned vehicle that located on the forward part of the ICC); can be configured to provide the International – the Equipped Avionics Bay (EAB), which Space Station (ISS) with up to 5500 kg of dry accommodates most of the avionics equip- supplies (e.g. hardware, food and clothes) and ment (some avionics items such as rendez- liquid and gas supplies (up to 840 kg of water; vous sensors are located in the ICC and EPB); up to 100 kg of gases (air, nitrogen, oxygen); up – the Solar Generation System (SGS), which to 860 kg of refuelling propellant). ATV can includes four 4-panel deployable solar wings, provide propulsion support to the ISS by using each with its own drive mechanism. up to 4700 kg of propellant. The total net payload is estimated to be at least 7500 kg. The ICC accommodates all cargo apart from Finally, ATV can also remove up to 6500 kg of the reboost propellant (carried in the waste from the Station. spacecraft) and consists of: – the Equipped Pressurised Module (EPM), The ATV Structural and Thermal Model (STM) test campaign began at which accommodates dry cargo in dedicated the ESTEC Test Centre in October 2001. ATV’s capabilities, mission, payload racks. ISS waste is carried for the configuration and development logic are outlined. The STM Test destructive reentry part of the ATV mission; Campaign and test objectives are then detailed. Some special – the Equipped External Bay (EEB), which is an requirements imposed by ATV’s size are described. The main test unpressurised assembly to house water, gas results and lessons learned are summarised. and refuelling propellant tanks; – the Russian Docking System (RDS), which provides capture and release for docking At least eight ATV flights to the ISS are planned with and departure from the ISS. Several as part of the European contribution to RDS models, including for the first ATV, are supporting ISS operations (Fig. 1). being provided by Russia as a barter for the European Data Management System that is ATV configuration currently operating in the Station’s Zvezda The ATV vehicle is composed of two elements Russian Service Module. (Fig. 2): the spacecraft (SC; including solar array) and Integrated Cargo Carrier (ICC). The ICC and SC are protected by the external Meteoroid and Debris Protection System The ATV spacecraft comprises: (MDPS) shield. – the Separation and Distancing Module (SDM), which provides the mechanical interface with ATV development logic and main system Ariane-5 and ATV’s separation and distancing models from the launcher; The ATV flight segment assembly, integration 95 r bulletin 111 — august 2002 Figure 2. ATV subassemblies and dimensions ATTITUDE CONTROL THRUSTERS Ø 4482 MAXI MDPS WITHOUT MLI RUSSIAN DOCKING SYSTEM (RDS) MDPS CC INTEGRATED CARGO CARRIER EQUIPPED PRESSURIZED MODULE (EPM) 4916 GAS, WATER AND RFS EQUIPPED EXT. BAY (EEB) 10773 AVIONICS EQUIPMENT CHAINS (AEC) EQUIPPED AVIONICS BAY (EAB) RADIATORS EAB MDPS EPB 3330 SOLAR GENERATION EQUIPPED SYSTEM (SGS) PROPULSION BAY (EPB) ATTITUDE CONTROL AND SPACECRAFT BRAKING THRUSTERS SUBASSEMBLY SEPARATION PLANE SEPARATION AND 2000 DISTANCING MODULE (SDM) PROPELLANT TANKS MAIN THRUSTERS 96 automated transfer vehicle and verification during Phase-C/D uses three adequacy for ATV to save on delta-qualification system-level models: STM, Electrical Test or redesign. Another goal of the vibration tests Model (ETM) and Proto-Flight Model (PFM). (acoustic, sine) is to characterise the vibration environment experienced by ATV payloads in The STM is being used for environmental tests the payload racks. in the ESTEC Test Centre. After these tests, the SC will be subjected to static tests at The STM campaign began at the end of Contraves (CH). The ICC external bay will be October 2001. Figure 3 shows the test subjected to further dynamic and static tests sequence. (together with a flight-standard pressurised module). The STM pressurised module will be refurbished at Alenia (I) and eventually used for Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct crew training at the European Astronaut Centre in Cologne (D). STM Test Campaign The ETM is being used for functional Acoustic Test qualification testing of the ATV and for a first set 25/10 of vehicle/ground segment compatibility tests. Modal Survey Tests 17/12 After initial integration and electrical testing of Dynamic & SDM Tests the EAB ETM at Astrium SAS (F), the full ATV 15/04 ETM (including the ETM models of the avionic Shock Tests equipment in the ICC and EPB) will be 06/05 integrated at EADS Launch Vehicles. SGS Deployment Tests 03/06 Thermal Test The PFM, now named ‘Jules Verne’, will be 17/06 subjected to the following environmental and 12/08 EMC Test functional tests: – acoustic Packaging 21/08 – electromagnetic compatibility – solar wing deployment End of campaign – clampband release –thermal test (EAB level) 10/09 – final set of vehicle/ground segment compatibility tests – complementary electrical and functional STM representativity Figure 3. STM ESTEC test qualification tests The SDM model consists of a flight- campaign sequence – functional acceptance. representative structure, with a real clampband separation device equipped with connectors, The ATV Flight Segment prime contractor for but no distancing spring. The rest of the SC Phases-C/D (development, manufacture, structure has only minor differences from the integration of first vehicle and associated Flight Model. Its equipment mock-ups are ground support equipment, as well as ATV dynamically and thermally representative; the qualification) is EADS Launch Vehicles (Les stiffness at bracket interfaces is representative Mureaux, F). The main contractors responsible of the Flight Model, and there is 80% of the for the subsystems and/or the ATV sub- EPB harness and plumbing. Propulsion assemblies are: subsystem tanks are fillable structural mock- – Astrium GmbH (Bremen, D), propulsion and ups. The Thermal Control System is fully flight- reboost subsystem, SC integration representative. One solar wing is mechanically –Alenia Spazio (Turin, I), ICC flight representative; the other three are – Astrium SAS (Toulouse, F), avionics sub- simulated by single-panel mock-ups (identical system, EAB integration mass and area as folded wings). – Contraves (Zurich, CH), SC structure sub- system The ICC STM is dynamically representative of –Dutch Space (Leiden, NL), solar array. the Flight Model. The EPM (replaced by a special mock-up for thermal testing) structure Testing at ESTEC includes a cylindrical shell and aft and forward The main objective of the STM test campaign is conical parts. The EEB shows minor to verify the vehicle’s mechanical and thermal differences with respect to Flight Models. behaviour. Since many ATV components are Racks are flight-standard. The Russian either derived or directly reused from previous Docking System (RDS) is a mechanically and programmes, the dynamic tests are of thermally representative mock-up. The ICC particular importance for confirming their forward cone features a mechanical mock-up 97 r bulletin 111 — august 2002 of a rendezvous sensor, on its dedicated – low-level run (to check sensors’ individual support. ICC gas tanks are structural models responses and to assess structural integrity with masses representative of filled tanks. after the testing): overall level 141 dB for 60 s. Refuelling System (RFS) kits and water tanks are fillable structural models, with dummy Achievement of homogeneity and the specified valves and partial plumbing. test spectrum took less than a minute for each test run. After the first run, microphone Acoustic test positioning was optimised; they were moved Characterisation of the vibro-acoustic response further from the STM, outside the acoustic of ATV to the acoustic levels induced by the homogeneous field. This unusual setting was Ariane-5 launch and flight was the major due to the STM’s size, which fully occupied the requirement of the acoustic test. The final goal LEAF acoustic homogeneous field. During the was to compare acoustic and random vibration qualification-level run, nitrogen aerodynamic levels to those specified for ATV’s major noise at 4 kHz in the LEAF made the target components and equipment. Tests were input level in this non-critical band impossible performed in December 2001 in the Large to tune precisely (higher levels than required European Acoustic Facility (LEAF) at ESTEC. were achieved). Figure 4. ATV on the All these tests were successfully Acoustic Stand in LEAF performed within 4 days. Qualifica- tion random levels for equipment are in the process of being confirmed by test-result analysis. Modal survey The test characterised the global dynamic behaviour of the complete ATV: the main longitudinal and lateral structural eigenmodes of the ATV, and (when uncoupled) the eigen- modes of the vehicle’s main components. Eigenfrequencies and shapes, effective and generalised masses and damping factors of the eigenmodes were produced by modal survey tests. These results are being used for updating the ATV mathematical model for ATV/ Ariane-5 coupled load analysis. The modal survey logic was based on two test configurations with different fluid and dry-cargo loadings. In reality, ATV will carry a wide range of payload combinations. Both ATV with a total mass of 15 t (low loaded configurations had a mass of around 20 t. The configuration) was mated with the Acoustic first used an extreme payload distribution Uncoupling Stand (AUS, Fig.