National Aeronautics and Space Administration

Wallops Flight Facility

Announcements

GFO End of Mission

Due to increasing sun exposure (minimal eclipse), the temperature of the GFO platform increased to
the point where normal operations were no longer feasible. The final step was to keep the radar
altimeter (RA) off until after the “full sun” cycle. No GFO data was received after this date September 17, 2008.

The Navy officially declared the GFO Mission was ended as of October 22, 2008.

WVR is back on, RA is being power cycled during eclipse periods.

The satellite is currently at the end of the 135th repeat cycle — after a partial resolution of the continuing issues with the batteries, the WVR is back on full time, but the RA is being power cycled so that it is off during eclipse periods. Both these payloads will be cycled on and off as necessary to maintain the satellite electrical power system and prevent satellite resets.

GFO RA and WVR payloads off

As of 27 January 2007 (2007 027) the satellite has completed 131 exact repeat cycles and has spent over five years on orbit since acceptance of the satellite by the Navy and over eight years on orbit since launch. The satellite is currently in the middle of the 132nd repeat cycle — due to continuing issues with the batteries, the RA is off as is the WVR. Both these payloads will be cycled on and off as necessary to maintain the satellite electrical power system and prevent satellite resets.

GFO radar altimeter back online.

GFO satellite systems came back online as of approximately 13:00z on 5 Oct 06, day 278. The ADFC has implemented a -82.4 millisecond timing bias into the SDR processing. The ADFC transitioned the latest POC software, SDR with WVR flagging, to operational mode on 2006291.

GFO radar altimeter back online.

GFO satellite systems came back online as of approximately 16:50z on 23 Aug 06. The WVR was turned on at 16:30z on 23 Aug 06. The payload started producing high quality data as of 16:06:23z on 24 AUG 06. The ADFC has begun processing the data on 24 Aug 06 and data delivery has resumed.

GFO radar altimeter powered off

GFO’s power control unit initiated a low bus voltage payload bus load shed last night (Aug. 25 between 00:40z and 3:00z). As a result the RA and WVR are currently powered off. This event is currently under investigation.

GFO radar altimeter powered off

On August 3, 2006, GFO experienced 3 low voltage (UV1) alarms resulting in the shedding of the payload bus. The battery state and charge is under investigation. The altimeter has been off since this event occurred.

Full Waveform Data Collection suspended 15 October 2005 – 7 April 2006

The number of full cal periods will be occasionally reduced to support battery maintenance. Ten minute CAL was performed but there was no Full Wave Form data collection. GFO Full Wave Form was restored on 7 April 2006.

Outage due to hurricane Katrina on 24 August 2005

Due to hurricane Katrina, which caused power and communication outages across the gulf coast, the NAVO ground system was totally out, the satellite remains operational and data is being archived by the Naval Satellite Operations Center. The GFO POC resumed sending data on 15 September 2005. Nearly all data during the outage period has now been processed and made available.

One RA Calibration Period Discontinued on 13 March 2005

One of the two daily RA CALS to collect data over Africa was discontinued.