_                   
                                                         |_|                  
      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 STATUS

There is good news and there is bad news regarding HALCA's status! HALCA's onboard computer was successfully rebooted on October 29th according to plan. When the short season of eclipses ended the following week, HALCA was taken out of the slow-spin mode, the reaction wheels (used for regular maneuvering) re-started, and check-out of the on-board system commenced. It had been hoped to start observing on November 9th, but re-setting HALCA's power control system and re-establishing the ku-band (15 GHz) tracking station links took longer than anticipated and so observing was scheduled to restart on the 15th.

Observations were just about to get underway on Sunday 15th when word was received from the ku-band tracking stations that there was no signal from HALCA! (Once again, the variation of Murphy's Law -- which states HALCA's problems will always occur on weekends when there are less S-band tracking passes available to check its status -- prevailed.) During Monday's S-band Kagoshima pass it was found that the Data Handling Unit had again stopped operating correctly making it impossible to lock onto the down-link telemetry. As the failure happened between tracking passes and while the on-board Data Recorder was not in use, it is very difficult to determine what event triggered the DHU failure, however a range of possible causes is being investigated. As demonstrated on October 29th, the recovery procedure for re-booting the DHU works well. Unfortunately, the best way to carry out this procedure requires the satellite passing through the Earth's shadow and the next such eclipse is not until late January 1999. While this is the current fall-back position, the possibility of attempting to re-boot the DHU before the end of this year is being actively investigated. More news on the chances of an early recovery will be given in the next VSOP news.

AO2 NOTIFICATIONS

Principal Investigators, or their designated contact people, will be e-mailed the status of their AO2 proposals next week. It had been hoped to include accurate estimates of the likelihood that each observation would be carried out (and to give tentative observation dates), but due to the uncertainty surrounding the time of HALCA's recovery this is clearly not possible. The e-mails will simply describe the Science Review Committee's ranking of the proposal and list any modifications recommended to the proposal by the SRC, or resulting from another proposal for the same source being higher ranked.

CORRECTIONS

In the last issue we mistakenly referred to the EVN/JIVE Symposium as (a) the JIVE Symposium and (b) the JIVE/EVN Symposium! JIVE is still a member of the EVN and not, as we appeared to imply, the other way around!

 
                Editors: Phil Edwards and Hirax Hirabayashi