_                    
                                                         |_|                   
      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

Satellite operations during the last week have been very busy, and ultimately very successful. During the first tracking pass from Kagoshima it was confirmed that the solar paddles and Ku-band antenna had deployed. Since then the star trackers have been switched on and found to be working well, with Achernar (apparent magnitude 0.5) standing out clearly in the first images sent back. The GPS system, included on the satellite for use in experiments to determine its usefulness in orbit determination, was given its first check-out earlier this week, and is scheduled for further testing this weekend. The on-board radio astronomical system was turned on for the first time, and the power levels checked across the observing bands. Finally, it was confirmed that the Ku-band telemetry antenna could be pointed correctly. A productive week!

ORBIT

HALCA's injection orbit had an apogee height of 21,250 km and a perigee height of 220 km. Three perigee raising maneuvers have been conducted since then. These maneuvers are conducted when the satellite is at apogee, and when apogee coincides with a Kagoshima Space Center tracking pass, so that the maneuver can be monitored in real time. The satellite is travelling at a little over 2 km/s at apogee, and the perigee raising is performed by using the hydrazine thrusters to add of the order of 12 m/s to the velocity in the direction tangential to the orbit. This raises the perigee height without affecting the apogee height. The first `perigee-up' maneuver increased the height to about 350km, and the second raised the altitude to just under 500 km. A third maneuver, conducted last night, has raised the perigee height to about 575 km.

MAIN ANTENNA DEPLOYMENT

The sub-reflector and main antenna deployment are scheduled for next week. After the sub-reflector deployment the satellite is turned away from the sun, and the main antenna then deployed. The extension of the six antenna masts will take about 30 minutes, and the complete antenna deployment about 2 hours, if all proceeds smoothly. The deployment has been scheduled for a long KSC tracking pass just in case any additional time is required.

NEW VSOP TEAM MEMBER

Jim Lovell joined the VSOP team this week, arriving from the University of Tasmania to take up a Japan Society for the Promotion of Science fellowship. Although Tasmania and Tokyo have quite similar longitudes, Jim has discovered that the time difference between the two places is two hours and six months!

 
 
       Editors: Phil Edwards and Hirax Hirabayashi