Reference: RO-OCN-TR-3005
Issue: 1.0
Date: 03.08.1999
CONSERT
Orbiter antenna Strength Load test
Antenna Centrifuge Test REPORT
1. INTRODUCTION
This document describes the procedure to be used for the Strength Load qualification test of the orbiter antenna of the CONSERT instrument on the Rosetta project. The Strength Load test will be carried out in a centrifuge.
2. APPLICABLE DOCUMENTS
EID-A Issue 1 Rev 1 Dated 15/6/1998 Ref: RO-EST-RS-3001/EID-A
3. DESCRIPTION OF THE ANTE NNA
The CONSERT orbiter antenna is composed of two half wave dipoles placed perpendicular to each other and with corresponding reflectors. In the folded condition the dipole elements, the reflector elements, and the two supporting masts, are collapsed parallel to each other, placed against three supports, and secured by a wire to the center support.
The total antenna mass is 1.45 kg
The figure shows the folded antenna.
FIGURE (e.g. figure 8 in TV procedure)
The antenna coordinate system is given in Figure 2.2-2a in the EID-B.
4. TEST CONDITIONS
Cleanliness 100000
Temperature 20 degrees C
Humidity < 50%
5. TEST GOALS
It is to be verified that the antenna can withstand a force equivalent to 55g along each one of the X-, Y-, and Z-axis in both the positive and negative directions. The 55g is derived from 'Figure 2.2.5.2 (Design load)' of EID-A for the given mass of the antenna.
6. TEST FACILITY
The force required for the Strength Load test will be provided in a centrifuge.
The antenna will be placed with the corresponding axis ('+' or '-') lined up such that the resulting force, which is the combination of the Earth's gravitational field and the centrifuge field, is parallel to that axis.
A description of the centrifuge that will be used in these tests is attached.
Centrifuge key parameters:
Maximum pay load 2 ton
Maximum radial acceleration 250 g
Model area 125x125 cm
Maximum model height 180 cm
Effective radius 412.5 cm
The facility allows video taping of the antenna during the test runs. Furthermore, a recording of acceleration versus time will be provided. The video tape will have time imprinted, so that a relationship between acceleration and visible deformations of the antenna can be made.
During each test run the total acceleration will be slowly increas ed over several minutes to the maximum wanted acceleration. Then the acceleration will be kept at the maximum value for about 10 seconds, before it again is slowly reduced.
MPAe will provide the test-fixtures for placing the antenna in the centrifuge.
The Centrifuge will be operated by the centrifuge-team of the University of Bochum.
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7. TEST STEPS
Test OK? Video OK? G vs Time OK?
Y/N Y/N Y/N
1. Unpack, and visual inspection of the antenna
2. Mount antenna for acceleration in the +Y direction
2a. Picture of mounte d antenna
3. Run test to 55 g ......... ........... ...............
4. Mount antenna for acceleration in the -Y direction
4a. Picture of mounted antenna
5. Run test to 55 g ......... ........... ...............
6. Mount antenna for acceleration in the +Z direction
6a. Picture of mounted antenna
< P ALIGN="JUSTIFY">7. Run test to 55 g ......... ........... ...............8. Mount antenna for acceleration in the -Y direction
8a. Picture of mounted antenna
9. Run test to 55 g ......... ........... ...............
10. Mount antenna for acceleration in the +X direction
10a. Picture of mounted antenna
11. Run test to 55 g ......... ........... ...............
12. Mount antenna for acceleration in the -X direction
12a. Picture of mounted antenna
13. Run test to 55 g ......... ........... ...............
14. Visual inspection - no change
15. End of Test