Tohban Report 2012-07-18

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Tohban Reports
Start Date: 11 July 2012
End Date: 18 July 2012
Tohban: Claire Raftery
Tohban email: claire@ssl.berkeley.edu
Next Tohban: Hazel Bain
List all reports



Solar Activity

Activity has decreased from last week but NOAA 11520 produced multiple M class flares, and one X class flare. In addition, it produced a very unusual M flare on 2012/07/17. This long-duration event had an almost symmetrical soft X-ray lightcurve, with a ~6 hr rise phase and ~6 hour decay. RHESSI data has not yet been downlinked.

How many GOES flares occurred? 

 Flares above B, C, M, X class were      0    35     2     1

And how many of these are listed in the RHESSI flare list? 

 Flares above B, C, M, X class were      0    22     0     1

And how many had EXCELLENT coverage? 

 Flares above B, C, M, X class were      0     9     0     0

There were RHESSI flares/GOES flares 293 / 38 over the time range 11-Jul-12 18-Jul-12

Memory Management

SSR has been varying between 22-50%. Extra passes were supplied until 7/17/2012. The SSR rose gradually (i.e. not associated with M flare) from 20-40% over the course of 7/17/12. This was due to data replays. Consider returning to normal/vigorous decimation if SSR gets down to "normal" levels.

Spacecraft Status

The cryocooler power was increased from 70-78W on 7/12/12 in an attempt to reduce the cold plate temperatures which began at 106 and 105K. Over this week, they have shifted to 106.2 and 104.7K. The cold tips are at 88K and 90K. The accelerations are at 17mg, up from 13 mg. Overall, increasing the cryocooler power has not had a significant (if any) effect on the temperature of the cold plates. The small reduction can be attributed to moving from the peak of the sun fraction period, into the declining phase.

From Brian Dennis:

"Here are seven plots I made to show the effects of increasing the cryocooler power from 71 to 78 Watts on 12 July. The plots show various state-of-health parameters plotted as a function of time from 1 November 2010 to 16 July 2012. As the last plot of cold plate temperature #2 vs. time shows, it seems that the net effect of this increase in power was a reduction in this temperature of about 0.5 K from what it would have been if we had kept the power the same. This was at a cost of increasing the cryocooler electronics temperature to almost 50 C and the accelerometer amplitude from about 13 to 17 mG. The cryocooler efficiency also went down noticeably. We are near a minimum in Sun Fraction so the Cold Plate temperature is near a local maximum. The next maximum in Sun Fraction will take place near the beginning of August following the pattern in 2011 but I don't expect this to have a significant effect on the change in temperature resulting from the increase in power.

Brian"

Summary of discussion at meeting

  • 0.5 degree reduction in temps.
  • End of night voltage reduced from 26.5->26 volts. This is low. Passes currently in daylight. This will get worse when passes are at night because transmitter is on at night, drawing more power. We need to stay above ~24 V.
  • CP2 max of 105K at peak of cycle - not worth having power up at 78 W.
  • Next peak expected in August, half the height of previous one.
  • No reason to expect that running cooler at high wattage for longer will reduce the temps.
  • Efficiency of cryocooler has dropped significantly with higher power.
  • Brian proposed lowering the power.

-> How tolerant are we of temp increase when we lower the cooler power.

  • Go back to 71 watts for a week.
  • Debate LOWERING power when sun fraction is not changing rapidly (in ~week).
  • Possibility of charging battery harder (VT3 -> VT4??)
  • Mark reluctant to charge harder because it tends to cause issues.
  • Recommendation: return to 71 W. Debate changing to ~60W, perhaps next week.



Data Gaps

DATA GAPS FOR 2012/07/17
TIME RANGE: 2012-07-17T00:00:00.000 -- 2012-07-18T00:00:00.000
GAPS IN APP_ID = 1 (VC1-SOH) WITH PACKET RATE LT 30
N_GAPS           1
GAP START TIME              GAP END TIME                   GAP (SEC)
2012-07-17T22:55:00.000 -- 2012-07-18T00:00:00.000       3900.0000
GAPS IN APP_ID = 154 (VC1-PMTRAS) WITH PACKET RATE LT 4
N_GAPS           1
GAP START TIME              GAP END TIME                   GAP (SEC)
2012-07-17T22:55:00.000 -- 2012-07-18T00:00:00.000       3900.0000
GAPS IN APP_ID = 102 (VC3-MONITOR RATES) WITH PACKET RATE LT 30
N_GAPS           2
GAP START TIME              GAP END TIME                   GAP (SEC)
2012-07-17T05:05:00.000 -- 2012-07-17T05:10:00.000       300.00000
2012-07-17T06:25:00.000 -- 2012-07-18T00:00:00.000       63300.000



DATA GAPS FOR 2012/07/16
TIME RANGE: 2012-07-16T00:00:00.000 -- 2012-07-17T00:00:00.000
GAPS IN APP_ID = 1 (VC1-SOH) WITH PACKET RATE LT 30
N_GAPS           2
GAP START TIME              GAP END TIME                   GAP (SEC)
2012-07-16T16:20:00.000 -- 2012-07-16T16:35:00.000       900.00000
2012-07-16T18:00:00.000 -- 2012-07-16T18:15:00.000       900.00000
GAPS IN APP_ID = 154 (VC1-PMTRAS) WITH PACKET RATE LT 4
N_GAPS           2
GAP START TIME              GAP END TIME                   GAP (SEC)
2012-07-16T16:20:00.000 -- 2012-07-16T16:35:00.000       900.00000
2012-07-16T18:00:00.000 -- 2012-07-16T18:15:00.000       900.00000
NO GAPS IN APP_ID = 102 (VC3-MONITOR RATES)




DATA GAPS FOR 2012/07/14
TIME RANGE: 2012-07-14T00:00:00.000 -- 2012-07-15T00:00:00.000
NO GAPS IN APP_ID = 1 (VC1-SOH)
NO GAPS IN APP_ID = 154 (VC1-PMTRAS)
GAPS IN APP_ID = 102 (VC3-MONITOR RATES) WITH PACKET RATE LT 30
N_GAPS           1
GAP START TIME              GAP END TIME                   GAP (SEC)
2012-07-14T12:05:00.000 -- 2012-07-14T12:10:00.000       300.00000



DATA GAPS FOR 2012/07/13
TIME RANGE: 2012-07-13T00:00:00.000 -- 2012-07-14T00:00:00.000
NO GAPS IN APP_ID = 1 (VC1-SOH)
NO GAPS IN APP_ID = 154 (VC1-PMTRAS)
GAPS IN APP_ID = 102 (VC3-MONITOR RATES) WITH PACKET RATE LT 30
N_GAPS           1
GAP START TIME              GAP END TIME                   GAP (SEC)
2012-07-13T18:20:00.000 -- 2012-07-13T18:25:00.000       300.00000


Detector issues

Detector 8 is noisy coming out of SAA - lengthened decay phase after SAA. http://sprg.ssl.berkeley.edu/~tohban/browser/?show=grth1+qlpfr+monfs+monfl+monfr+monff&date=20120713&time=013739

Other notes

Spinup required.

btaps tutorial:

  • Facility -> HESSI
  • PKT -> times
  • Mnemonic selector -> try substring selector ->Select Bat Voltage (double click or add)
  • Can change "show plots" to have multiple plots.

Spacecraft Management

Decimation Active/vigorous (as of day 184)
HLAT Decimation
Night time data (fronts) +/- 4 minutes
Night time data (rears) +/- 4 minutes
Require extra passes? No
Requirement for moving pointer? No
Attenuator operation Normal
Detector problems? Not significant ones.
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