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UNIVERSITA' DI PISA

Dipartimento di Matematica
via Buonarroti, 2
56127 - Pisa
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  The Galileo Galilei(GG) project (see also the web site of the mission)

GG orbit

Galileo Galilei (GG): a space mission aimed to test the equivalence principle at the level h=10-17.

altitude: about 520 km
orbit:circular sunsyncronous orbit with Iclination I=97.5 degrees
mass:300 kg
GG satellite
The satellite spins around its symmetry axis at a rather high frequency (2 Hz with respect to the center of the Earth) and this rotation provides passive stabilization of the spacecraft attitude (the axis of symmetry is also the axis of largest moment of inertia) and an high frequency modulation of expected signal (reduction of "1/f" electronic and mechanical noise).

 

2 ACCELEROMETERS CENTERED ON CM OF THE SPACECRAFT:

internal for EP testing:

two hollow coaxial cylinders of different composition,
10 kg each, planned to be made from Pt/Ir and CuBe.
GG apparatus

external for systematic checks:

two hollow coaxial cylinders (10 kg each) of equal composition.
The instrument is inherently differential: test bodies are coupled by the read out and by very weak suspensions like in an ordinary beam balance for higher sensitivity to differential forces.

The read out system is made of two pairs of capacitance plates located halfway in between the test cylinders. It works at room temperature.

GG sensitivity plane The sensitivity plane is the plane perpendicular to the symmetry axis. This improves sensitivity by a factor 2 with respect to experiments having only one sensitive axis.
  ... see more pictures and the film of the GG satellite at the page GG sketches
...and something more ABOUT ME...
    modified: 2 august 2003