_                    
                                                         |_|                   
      V   V   SSSS   OOO   PPPP                 \__      |_|      __/          
      V   V  S      O   O  P   P                   --____/ \____--             
      V   V   SSS   O   O  PPPP                    _ _ _ --- _ _ _             
       V V       S  O   O  P                      |_|_|_|  @|_|_|_|            
        V    SSSS    OOO   P                             o-o                   
                                                          /                    
      ***  N    E    W    S  ***                        <)                     
 

********** HALCA DEPLOYMENT SUCCESSFULLY COMPLETED! **********

HALCA's sub-reflector was deployed during Monday evening's (JST) tracking pass. The 110cm diameter, hexagonal sub-reflector is supported on three legs, each of which are hinged in two places. Deployment took only a matter of minutes, and the sub-reflector is now in position 3.4m above the main antenna surface.

The deployment of the main antenna started early Thursday morning (JST). First the plates holding the antenna mesh against the satellite body were released. The deployment then required the six masts to be extended to their full extent, and then the tensioner at the end of each mast extended an additional 3cm to tighten the mesh. At first the masts were extended in pairs by about 10mm, to ensure the extension motors were functioning. The masts were then driven out to a little short of their full 4.8m length, which took about 10 minutes. As the extension speeds of the masts differed, the masts were then driven individually to bring them just short of full extension. Then, one by one, they were driven to full, locked extension. With the tension in the mesh (not to mention the control room!) increasing, it was perhaps not surprising that the last mast at first refused to move the final 5cm. A second attempt extended the arm one more centimetre. The tensioners were then all partially extended and then retracted to straighten out any kinks in the mesh. The mast then extended another 2cm before stopping, just under 2cm short of its goal. As the tracking pass was drawing to a close, it was decided to wait a day before completing the deployment.

The routine housekeeping and commanding were carried out at the beginning of this morning's pass, before trying to coax the last mast to its full extent. The tensioners were again partially extended and retracted. Breathing ceased in the Kagoshima and Sagamihara control rooms as the command was sent to the mast extension motor to start. The mast smoothly and steadily extended the remaining 2cm and the `full extension' status sign flashed up on the telemetry screens. Breathing recommenced! The tensioners were then driven out the final 3cm to their full extension and locked into place. The antenna was deployed!

WHAT'S IN A NAME?

It may be the Highly Advanced Laboratory for Communications and Astronomy, but Tapasi Ghosh (Arecibo) notes that HALCA means `light' or `floating' in Bengali (national language of Bangladesh and one of the official languages of India)!

With the last mast refusing to cooperate, the most pessimistic outlook was that 22GHz observations would only be possible with a significantly reduced gain. Although testing of the antenna surface accuracy has yet to commence, it is tempting to dub the satellite HALCKA, as it now seems highly likely that observations at L-, C- and K-band will all be possible!

 
 
       Editors: Phil Edwards and Hirax Hirabayashi