| Date: | 2001-01-26 09:20:00 | |
| Sender: | Scott Wetzel, NASA SLR <Horvath, Julie E. <Julie.Horvath@honeywell-tsi.com>> | |
| Subject: | [SLR-Mail] No. 724: GFO-1 Interruption | |
| Author: | Scott Wetzel, NASA SLR | |
| Content: | ******************************************************************************** SLR Electronic Mail 2001-01-26 09:20:00 UTC Message No. 724 ******************************************************************************** Author: Scott Wetzel, NASA SLR Subject: GFO-1 Interruption > Dear Colleagues, > > We have received notification from the GFO-1 team that they are > experiencing minor problems with the spacecraft and are currently > determining their course of action. They are experiencing problems with > reaction wheel 3 and appears to be applying more torque than required. > Ball Aerospace (the GFO-1 builder), has taken a quick look at the > telemetry data and determined that although the IAP is sending a specific > torque request to the wheel, it is applying a larger torque. There are > several trouble shooting steps currently under consideration. > Furthermore, Ball has recommended that the GFO-1 team not perform a > maneuver (one will be needed within the next 4-5 days) with wheel 3 > acting in this manner. On the pass scheduled for Day 26 0025Z the team > will shift to wheel 4, unless there is an indication that the change in > loads has resolved the anomaly. If they shift to wheel 4 the intent is to > further analyze the data and then make a decision on a troubleshooting > plan. > > During the DOY 26 pass from 00:25:57zto 00:37:05z GFO-1 will be put in > acquire sun mode to facilitate the transition to the redundant reaction > wheel. The satellite will lose nadir pointing for this time, consequently > the array will also lose nadir pointing during this time. > > During this period of trouble-shooting, please continue to attempt > tracking with GFO-1 unless the situation degrades further or the satellite > remains to hold in a non-nadir attitude. Please disregard the earlier > maneuver notification. When the maneuver is rescheduled, you will be > provided further information. > > Thank you for your patience and continued support on this matter. > Scott L. Wetzel, SLR Mission Operations Manager > NASA Satellite Laser Ranging Program > Honeywell Technology Solutions Inc. > Phone: 301-805-3987 > Fax: 301-805-3974 > E-mail: scott.wetzel@honeywell-tsi.com > From: ”Horvath, Julie E.” ******************************************************************************** |