From: Al Frandsen Subject: ACE Status for the Week Ending December 12, 1997 >Date: Fri, 12 Dec 1997 11:52:37 -0500 >From: Don Margolies >Subject: ACE Status for the Week Ending December 12, 1997 > >Good Morning Everyone, > >It looks like we've made a turn into the home stretch and by tomorrow >morning we should all be winners. The ACE Flight Operations Team and >Flight Dynamics Group began Halo Orbit Insertion (HOI) maneuvers on >Tuesday, December 9. We had a slow start due to some nutation that was >introduced into ACE, however that issue was resolved and the thruster >firings began. Today we plan to complete the last six thruster operations >(about 50 minutes each) and by tomorrow morning should be in the halo >orbit. Once we have an opportunity to establish orbital parameters we may >decide on a trim maneuver sometime next week. > >Prior to the start of HOI all instruments that could be affected by the >thruster plumes were shut down by the respective teams. They will be >restarted during the next week, depending on the magnitude of a trim >maneuver, if any. The observatory data link was configured to the broadbeam >antennas and the data rate reduced to 434 bits per second. This provided us >with the maximum data link reliability during the operation. The solid >state recorders are capturing data at the normal rate during this period. >They will be dumped and reviewed as required. We did dump the recorders >that contained data from the December 9 nutation incident. This data will >be reviewed off line so that we have a thorough understanding of how the >observatory responded and how quickly it damped out the nutation. > >During the last three and a half months much has happened on ACE. It was >supposed to be a period of transition and checkout but it turned out to be >a go for broke operation, especially after the solar events of November. >Once the orbit is verified we will go through a period of detailed checkout >so that we can declare the mission operational in late January and hand off >responsibility to the Orbiting Satellites Project on February 1. > >I am extremely proud of the way that the ACE Team performed since August >25. They are professionals all the way. The Taxpayers money has been >efficiently spent on this project, and for that I say thank you to all who >had a part in it. > >I, and many others have quite a bit of "use-or-lose" leave to take before the >end of the year. Therefore I will be out of the office for the rest of the >year. I do not plan to have a weekly report submitted again until January. >Have a great holiday season and a happy new year to all. > >Don >