Terra Direct Broadcast (DB) is back on-line. The Direct Readout Laboratory (DRL) and the National Commission for the Knowledge and Use of Biodiversity (CONABIO) have acquired and processed data successfully.

The Flight Operations Team (FOT) is proceeding with recovery activities.  At today's meeting with the Terra Anomaly Resolution Team, we agreed to proceed with switching from the non-operational Direct Access System Module (DASM)-1 to DASM-2. This procedure involves two switches.  Based on their research of the available data on the two switches,  the engineering experts from the Goddard Applied Engineering and Technology Directorate (AETD) are comfortable with this approach.  We will hold a final Command  Authorization Meeting (CAM)  this afternoon to obtain approval to proceed with the recovery activity tomorrow, Friday, June 13, 2008.

The projected schedule, to be confirmed this afternoon, is as follows:
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Activities will start at approximately ~9:25 EDT, followed by a one-orbit wait period before turning on Direct Broadcast (DB). We plan to perform an engineering test of DB (turn DB on) at ~10:30 EDT.  We request those of you who can see the DB signal at this time to send a message regarding the data quality AS SOON AS POSSIBLE to: angelita.c.kelly@nasa.gov, eric.m.moyer@nasa.gov,  dante.j.berdeguez@nasa.gov, and julio.l.marius@nasa.gov.

The current plan is to remain in the engineering mode until we confirm that all systems are nominal. There may be interruptions of DB during this period. If all goes well, we expect to go to operational DB mode sometime this weekend. We will provide status updates as needed.

Please feel free to e-mail Angie Kelly at angelita.c.kelly@nasa.gov if you have questions. Thank you for your continued understanding and support.

Following the unsuccessful attempt to power on the Direct Access System Module (DASM)-1 last week, the Terra Anomaly Resolution Team has been evaluating 2 options for recovering the DAS capability.  The team continues to address the pros and cons of the two options, which involve switching to DASM-2.  At today's meeting, the team discussed the detailed procedures for each option.  There were questions regarding the two types of switches that would be involved and the reliability of each one.  The spacecraft manufacturer and the Flight Operations Team (FOT) are also addressing inconsistent information that has been found in the documentation.  The various engineering experts on the resolution team, including personnel from the spacecraft development team (Lockheed Martin) and engineering experts from the Goddard Applied Engineering and Technology Directorate (AETD), are leaning towards one of the options, pending additional switch reliability information.

The Terra Anomaly Resolution Team has asked the FOT to start focusing on the procedure development and simulations for the candidate option.  The team plans to meet later this week to go over additional information regarding reliability and contingency paths, and the results of the FOT's procedure development and simulation efforts. Barring unexpected developments, the team hopes to get agreement on proceeding, with a  recovery by early next week.  Once we turn DB on, we will need your feedback regarding the quality of the data.

Another status update will be published following the Terra Anomaly Resolution Team meeting later this week. Thank you for your continued understanding and support.

Initial attempts at controlling the voltage drop in the Direct Access System (DAS) Modulator side 1 (DASM-1) oscillator on Terra have not yielded much success.  Mission Operations is now reconfiguring to transition to DASM-2 (B-side) within the next couple of days. The DRL will notify the community when the transition occurs.

Terra Direct Broadcast was taken off-line on June 2, 2008, and is expected to remain off-line for the next few days. At 2008/150/21:08:58z, the Direct Access System (DAS) Modulator side 1 (DASM-1) Electrical Power Conditioner side 1 (EPC-1) experienced an anomaly that showed an unexpected current drop from 122.29 to 102.56 mA and a voltage drop from 5.00 to 4.62 V. In the same timeframe, the DASM-1 Oscillator temperature started increasing. In the hours that followed, the voltage trended lower. An anomaly consulting team was formed on Friday, May 30th. AETD engineers recommended that the Flight Operations Team (FOT) turn off the modulator if the voltage dropped below 3.5V to avoid the possibility of the circuit oscillating on and off. At 06:44:31 GMT on day 154 the FOT turned off the Terra DASM-1 due to excessively low voltage. The input voltage had dropped from the nominal 5V to 3.47. This action affects the availability of Direct Broadcast (DB) data through the X-band link. DB services are effectively suspended until further analysis and reconfiguration of the X-band link. All Science data continuesto be captured via Solid State Recorder and played back through the TDRS Network via K-Band.