Tohban Report 2013-05-08

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|tohban_name = Lindsay Glesener
|tohban_name = Lindsay Glesener
|tohban_email = glesener@ssl.berkeley.edu
|tohban_email = glesener@ssl.berkeley.edu
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|next_tohban  = TBA
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|next_tohban  = Hazel Bain
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== Solar Activity ==
== Solar Activity ==
-
There was a decent amount of activity this week, at least compared to recent months.  There are currently 8 active regions on the disk.  The most active this week was AR 11739, which spit out an M5 flare just after rotating onto the disk (on the 3rd) and many more C-flares with an occasional M in the days following.  It's now in the center of the disk but has decayed significantly, so is no longer so active.  I would expect that solar activity will continue at its current level (occasional C flares, nothing big).
+
There was a decent amount of activity this week, at least compared to recent months.  There are currently 8 active regions on the disk.  The most active this week was AR 11739, which spit out an M5 flare just after rotating onto the disk (on May 3rd) and many more C-flares with an occasional M in the days following.  It's now in the center of the disk but has decayed significantly, so is no longer so active.  I would expect that solar activity will continue at its current level (occasional C flares, nothing big).
How many GOES flares occurred?
How many GOES flares occurred?
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== Memory Management ==
== Memory Management ==
-
 
+
The SSR is emptying at the end of each pass set and reached a max of 27%.
== Spacecraft Status ==
== Spacecraft Status ==
 +
Cold plate temperatures are up slightly (due to daylight percentage), with CP2 at 111.3K.  The cryocooler power is at 71W, 2.7A.
 +
There were two commands sent to attempt to rebalance the cryocooler to a lower vibration amplitude.  This commanding was done yesterday (Tuesday).  Balancer amplitude and phase were changed simultaneously by 2 steps (1 step at a time).  As a result, the accelerometer amplitude decreased by about 1 mg, to ~14mg.  This effort will continue during the week.  (See note at end.)
-
== Data Gaps ==
+
The spin rate is down to 14.6 rpm, so it's time for a spin up, which will probably happen today.
-
There was no data gap this week.  
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There was a spin rate snafu on May 3/4.  Occasionally the magnetic field configuration is such that the ACS system does not sense any change in magnetic field as it spins, thinks something is wrong, and after a timeout period (5 min) goes into IDLE mode.  This problem happens (usually a few occurrences close together) about once a year or so.  The ACS system was commanded back to precession mode on the next available pass.  No ill effects remained from this issue. Here are the sequence of events:
 +
  2013-123-16:11 - ACS system went into IDLE mode due to spin rate miscalculation.
 +
  2013-124-02:08 - Ground command to precession mode
 +
  2013-124-03:42 - Autonomously transitioned back to Normal mode.
-
== Detector issues ==
 
 +
== Data Gaps ==
 +
There were no data gaps this week.
-
== Other notes ==
 
 +
== Detector issues ==
-
<Cryocooler>
+
Detector 9 is once again showing occasional "dropouts" or noise, depending on how you want to think of it.  These were short occurrences, not extreme, and occurred around the following times:
-
On April 25, during passes at 03:30 UT and 05:30 UT, a rebalancing of the cryocooler was performed as a measure to lower the power consumption and the overall increase trend in temperature. However, increasing/decreasing of both amplitude and phase of the balancer only led to vibration increase. The amplitude and phase of the balancer were put back to original values.
+
*May 7:  11:09
 +
*May 6:  11:19, 9:42
 +
*May 5: 9:54, 1130
 +
*May 4: 1937, 1803, 1625, 1004
 +
*May 3: 1152, 1015
-
Brian reported further changes in state-of-health plots.  Since last week, the Sun fraction has increased to peak at 0.71 and the Cold Plate 2 temperature has decreased to 111 K. This is to be compared with 106.5 K at the time of the previous similar peak in the Sun fraction that occurred about Feb. 10. So there has been a 4.5 K increase in about 2.5 months or about 20 K per year. The accelerometer reading has stayed constant just below 16 mg for the last week or so.
+
Since the problem is not severe, it was decided to not take any corrective action (i.e. changing the HV) yet, because it would be difficult to tell if it were helping. We'll wait for it to get worse first. In happy news, some preliminary analysis of flares during these noisy periods show *no* degradation in imaging for detector 9. One flare does show a slightly reduced flux for D9 (currently under investigation) but the other flare shows no reduced flux, meaning that the dropout-identification features in the RHESSI software are correctly identifying and correcting these dropouts. Further work and plots to follow!
-
Next course of action would be to rebalance with finer steps and to adjust both amplitude and phase simultaneously.
 
 +
== Other notes ==
-
<Gamma Ray Burst>
+
The rebalancing of the cryocooler will continue this week.  The current plan is to continue changing the balancer amplitude and phase simultaneously in various steps across two axes.
-
RHESSI detected a large GRB event at 07:47 UT of April 27. An initial report can be found in the Nugget article by Andre Csillaghy and David Smith ([http://sprg.ssl.berkeley.edu/~tohban/wiki/index.php/A_huge_gamma-ray_burst]).
 
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| Attenuator operation || Normal
| Attenuator operation || Normal
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|-
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| Detector problems? || No
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| Detector problems? || D9 noise, slight
|}
|}
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[[Category:Tohban Report 2013]]
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[[Category:Tohban Report]]
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[[Category:Tohban]]
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Latest revision as of 19:51, 29 August 2014


Tohban Reports
Start Date: 01 May 2013
End Date: 08 May 2013
Tohban: Lindsay Glesener
Tohban email: glesener@ssl.berkeley.edu
Next Tohban: Hazel Bain
List all reports



Contents

Solar Activity

There was a decent amount of activity this week, at least compared to recent months. There are currently 8 active regions on the disk. The most active this week was AR 11739, which spit out an M5 flare just after rotating onto the disk (on May 3rd) and many more C-flares with an occasional M in the days following. It's now in the center of the disk but has decayed significantly, so is no longer so active. I would expect that solar activity will continue at its current level (occasional C flares, nothing big).

How many GOES flares occurred?

 Flares above B, C, M, X class were      7    61     4     0

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

 Flares above B, C, M, X class were      5    39     4     0

And how many had EXCELLENT coverage?

 Flares above B, C, M, X class were      4    24     3     0

There were RHESSI flares/GOES flares 380 / 72


Memory Management

The SSR is emptying at the end of each pass set and reached a max of 27%.

Spacecraft Status

Cold plate temperatures are up slightly (due to daylight percentage), with CP2 at 111.3K. The cryocooler power is at 71W, 2.7A.

There were two commands sent to attempt to rebalance the cryocooler to a lower vibration amplitude. This commanding was done yesterday (Tuesday). Balancer amplitude and phase were changed simultaneously by 2 steps (1 step at a time). As a result, the accelerometer amplitude decreased by about 1 mg, to ~14mg. This effort will continue during the week. (See note at end.)

The spin rate is down to 14.6 rpm, so it's time for a spin up, which will probably happen today.

There was a spin rate snafu on May 3/4. Occasionally the magnetic field configuration is such that the ACS system does not sense any change in magnetic field as it spins, thinks something is wrong, and after a timeout period (5 min) goes into IDLE mode. This problem happens (usually a few occurrences close together) about once a year or so. The ACS system was commanded back to precession mode on the next available pass. No ill effects remained from this issue. Here are the sequence of events:

 2013-123-16:11 - ACS system went into IDLE mode due to spin rate miscalculation.
 2013-124-02:08 - Ground command to precession mode
 2013-124-03:42 - Autonomously transitioned back to Normal mode.


Data Gaps

There were no data gaps this week.


Detector issues

Detector 9 is once again showing occasional "dropouts" or noise, depending on how you want to think of it. These were short occurrences, not extreme, and occurred around the following times:

Since the problem is not severe, it was decided to not take any corrective action (i.e. changing the HV) yet, because it would be difficult to tell if it were helping. We'll wait for it to get worse first. In happy news, some preliminary analysis of flares during these noisy periods show *no* degradation in imaging for detector 9. One flare does show a slightly reduced flux for D9 (currently under investigation) but the other flare shows no reduced flux, meaning that the dropout-identification features in the RHESSI software are correctly identifying and correcting these dropouts. Further work and plots to follow!


Other notes

The rebalancing of the cryocooler will continue this week. The current plan is to continue changing the balancer amplitude and phase simultaneously in various steps across two axes.


Spacecraft Management

Decimation Normal/vigorous
HLAT Decimation Rear decimation weight 6, no front decimation
Night time data (fronts) +/- 4 minutes
Night time data (rears) Taking data at nights
Require extra passes? No
Requirement for moving pointer? No
Attenuator operation Normal
Detector problems? D9 noise, slight
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