S. Schmidt et al./ Acta Astronautica 55(2004)409-420 separation, side load) Qualification of measurement technology(pressure sensors at wall) e Investigation into material behaviour under extreme thermal-mechanical conditions Film/ Detector Manufacturing of complex contours with adapted Radiation Holder stifFener rings for buckling loads Demonstration and verification of the metallic/ Fig. 6. Measurement principle of 3D CT. ceramic joining technique 3.1.. Manufacturing and design respect to their type, geometry and position in the com Based on the thermal and structu ponent. It is therefore possible to visualize material analyses, two Vulcain scaled nozzles were made ap- defects in the component volume, to effect local reso- plying the LPI method. The required fibre angle and lution and hence to make a comprehensive statement the wall-thickness progression of the nozzle compo- as regards quality. In addition, a dimensional measure- nent were set via the winding technique so as to be ment,i.ea complete, quantitative coverage of the con- tailor made. Due to the side loads calculated, special tour, can be effected Downstream data processing can stiffener elements were necessary in order to pre- thus serve to determine wall thicknesses and represent vent buckling of the nozzle. By laminating on ring nominal-actual contour comparisons. Fig. 6 illustrates elements and subsequent ageing and pyrolysis, an this principle. Through the continuous advanced de- integral positive compound between nozzle and stiff- elopment of the industrial CT systems, in particular ening element was generated For mant facture of the detectors, components that are 800 X 800 mm two nozzles, a newly developed polymer system was in size can be tested used which permitted reducing the manufacturing time by approx. 30% compared to the old polymer Both nozzles were coated for the hot-firing tests with 3. Development and test of CMc components a CVD-SiC layer. One of the challenges involved the interface design between ceramic nozzle and metal 3. Vulcain subscale nozzle extension combustion chamber. In particular the high tempera- tures occurring at the interface in the case of an area Within the framework of the tekan and astra ratio of 5 represented a particular challenge. Thanks Programme, two Vulcain subscale nozzles on the scale to an angular flange design, the use of flexible high of 1: 5 and with an area ratio of s=5-45 were de- ure seals and special clamping ring problem could be solved. Fig. 7 shows the two coated igned, made using the LPI technique and subjected C/Sic nozzle extensions to hot-firing testing on the Astrium test bench F3 (Ottobrunn )as well as on the dlr test bench P& The development and test objectives of the C/Sic 3. 1.2. Hot-firing tests nozzle extension were The Vulcain subscale nozzle extension was tested in two test se he with a maximum cham To study the compatibility and function of oxida- ber pressure of Pc =40 bars, and a se tion/erosion protection coatings for different mix- quence which comprised one single load point, with ture ratios(O/F=5-8) Pe=80 bars and O/F=6, for the entire test duration of Investigation into nozzle flow, flow separation 32 s, which was suficient to have full-flowing condi- (transient, steady) tions in the nozzle extension installed the 40-bar load Comparison with Vulcain (full-scale lateral case was specially performed to visualize the transi- loads/separation data. tion process from free to restricted shock separationS. Schmidt et al. /Acta Astronautica 55 (2004) 409 – 420 413 Fig. 6. Measurement principle of 3D CT. respect to their type, geometry and position in the com￾ponent. It is therefore possible to visualize material defects in the component volume, to e;ect local reso￾lution and hence to make a comprehensive statement as regards quality. In addition, a dimensional measure￾ment, i.e. a complete, quantitative coverage of the con￾tour, can be e;ected. Downstream data processing can thus serve to determine wall thicknesses and represent nominal-actual contour comparisons. Fig. 6 illustrates this principle. Through the continuous advanced de￾velopment of the industrial CT systems, in particular of the detectors, components that are 800 × 800 mm2 in size can be tested. 3. Development and test of CMC components 3.1. Vulcain subscale nozzle extension Within the framework of the TEKAN and ASTRA Programme, two Vulcain subscale nozzles on the scale of 1:5 and with an area ratio of  = 5–45 were de￾signed, made using the LPI technique and subjected to hot-3ring testing on the Astrium test bench F3 (Ottobrunn) as well as on the DLR test bench P8. The development and test objectives of the C/SiC nozzle extension were: • To studythe compatibilityand function of oxida￾tion/erosion protection coatings for di;erent mix￾ture ratios (O=F = 5–8). • Investigation into nozzle Oow, Oow separation (transient, steady). • Comparison with Vulcain (full-scale) lateral loads/separation data. • Upgrading/verifying of design tools (heat transition, separation, side load). • Quali3cation of measurement technology(pressure sensors at wall). • Investigation into material behaviour under extreme thermal–mechanical conditions. • Manufacturing of complex contours with adapted sti;ener rings for buckling loads. • Demonstration and veri3cation of the metallic/ ceramic joining technique. 3.1.1. Manufacturing and design Based on the thermal and structure-mechanical analyses, two Vulcain scaled nozzles were made ap￾plying the LPI method. The required 3bre angle and the wall-thickness progression of the nozzle compo￾nent were set via the winding technique so as to be tailor made. Due to the side loads calculated, special sti;ener elements were necessaryin order to pre￾vent buckling of the nozzle. Bylaminating on ring elements and subsequent ageing and pyrolysis, an integral positive compound between nozzle and sti;- ening element was generated. For manufacturing the two nozzles, a newly developed polymer system was used which permitted reducing the manufacturing time byapprox. 30% compared to the old polymer. Both nozzles were coated for the hot-3ring tests with a CVD-SiC layer. One of the challenges involved the interface design between ceramic nozzle and metal combustion chamber. In particular the high tempera￾tures occurring at the interface in the case of an area ratio of 5 represented a particular challenge. Thanks to an angular Oange design, the use of Oexible high￾temperature seals and special clamping rings, the problem could be solved. Fig. 7 shows the two coated C/SiC nozzle extensions. 3.1.2. Hot-4ring tests The Vulcain subscale nozzle extension was tested in two test sequences, one with a maximum cham￾ber pressure of pc = 40 bars, and a second test se￾quence which comprised one single load point, with pc=80 bars and O=F=6, for the entire test duration of 32 s, which was suIcient to have full-Oowing condi￾tions in the nozzle extension installed. The 40-bar load case was speciallyperformed to visualize the transi￾tion process from free to restricted shock separation