Interball-2 as space launching pad: MAGION-5 successful launch from Interball-2 spacecraft.


From: NATAN EISMONT
Aug 30, 1996


In August the 29th 1996 at 9 hours 38 minutes UTC MAGION-5 subsutellite has been succesfully separated from the main Interball-2 spacecraft.

Nominal value of the separation impulse was 0.3 m/s and its direction was along spin axis spin axis of the main s/c.This axis 3 hours before has been targeted towards Sun and the spin period of the main s/c was about 120 seconds.

After applying the mentioned impulse the orbital period of the subsatellite has to be increased by 1.17 seconds with respect to the main s/c period.It means that main s/c will go ahead along orbit by 12.5 km each day in the apogee region.

First analysis of the MAGION-5 telemetry has shown that some of the s/c booms and solar panels were not deployed. As a result the principal inertia axis which nominally has to be the spin axis was deviated from the nominal position by 33 degrees. This value has been estimated by solar sensor data processing presented at the Figure below.This Figure gives the projectiones of the Sun direction unit vector onto XY lateral plane of the subsatellite.

The spin period of the subsatellite according to the results of the solar sensor data processing was about 30 degrees.

The contact sensors of the main s/c did not confirm the subsatellite separation. So for reliable confirmation of this event the control torque has been applyed to the subsatellite to increase its spin rate .Duration of this impulse was 16 s. It cause the expected increasing of the spin rate and thus confirmed the subsatellite separation.So the conclusion has been reached that contact sensors failed but the separation was successful.

Thus after beginning the free flight the main problem with subsatellite became the power supply difficulties because of solar panels partial undeployment. The team headed by Dr. Pavel Triska is trying to solve this problem.



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