Video footage from the INTEGRAL vibration tests - explanatory text
- 16 August 2001: `INTEGRAL PLM, SVM mating at ESTEC'
- 30 August 2001: `INTEGRAL transport to shaker'
- 30 August 2001: `INTEGRAL z axis - sine tests (vibration tests)'
(start to 1 min 28 s)
The INTEGRAL payload module and service module are joined (or, `mated') for the first time at ESTEC, having been transported separately to ESA's test centre during the summer. In this first clip we see the payload module, which carries the instruments, being manoeuvred above the service module, which provides the interface to the launcher (for INTEGRAL this will be a Proton launcher). When the two modules have been successfully mated the spacecraft is then ready to proceed to the shaker for the vibration tests.
(1 min 28 s to 3 min)
The INTEGRAL spacecraft is carefully moved to the shaker for vibration tests. The yellow object on the spacecraft is SPI - the spectrometer which will provide important insight into astronomical objects by measuring very precisely the energy of the gamma rays emitted by these objects. The protruding black circular objects at the lower corners are the fuel tanks - there are four in total. The aluminium sheet (clearly visible on the right of the frame at 2 min 47 s) is a dummy solar array.
(3 min to 9 min 38 s)
Once INTEGRAL has been secured onto the test table preparations begin for the vibration tests. The purpose of these tests is to ensure that the spacecraft will survive the launch and will be able to function properly once it is in orbit. The yellow `ropes' hanging from the ceiling are slings supporting INTEGRAL. Two long white leg-like structures are conduits for the accelerometer connections - 240 accelerometers were placed throughout INTEGRAL to measure the effects of the vibrations. The red spaghetti-like cables attached to each accelerometer can be seen emerging from the end of the conduits. Emerging from the gold-coloured material (MLI - multi-layered thermal insulation which is used to protect the spacecraft from thermal fluctuations) at the top are two `tubes'. These are the star-trackers used for navigation and orienting INTEGRAL in space.
A series of vibration tests are performed at different frequencies. This set of tests, called the z axis tests because they test vibration along the `z-axis' of the spacecraft, are performed with the shaker operating in lateral mode. At about 4 min INTEGRAL can be clearly seen to vibrate. The first test concludes at about 5 min 30 s. Engineers and technicians then prepare for the next vibration test. (At about 8 min INTEGRAL is again vibrating strongly.)
For background to these tests and to read an eyewitness account see: `Whole lot of shakin' goin' on!'
For more on INTEGRAL and the individual instruments, go to the INTEGRAL website