ROSAT S/C Status 1998-08-31 ... 1998-12-03
Compiled by
Jakob Englhauser
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Mon 1998-08-31 (DoY 243)
No safemode up to this point.
04:32:15 WHM6 still not in safemode.
(300598 is in Earth block during Weilheim)
05:06:15 ---- slew to 202805
06:43:00 ---- return to nominal timeline
09:16:25 WPS several periods of steady and transient state
(probably since the contact started only a few minutes
after the ROSAT night)
14:30 AGO SAA throughout the contact (no X-ray data);
observed timeline events:
1) Earth block (transient)
2) no Earth block (transient, and steady)
3) update of actual quaternion
4) slew to new target at the end of the contact
20:08:30 WHM1 still ok; first transient (as expected for ROSAT night),
then Earth block
Tue 1998-09-01 (DoY 244)
23:24:45 WHM3 complete recovery of WFC (from scratch)
01:04:45 +WHM4 - all error messages of WFC (as seen since 1998-Apr)
disappeared
- WFC is observing again (HV on)
- accidentally the 'AMCS Restart of STCW' was disabled
(resets of STCW by AMCS are disabled)
07:30 WPS enable 'AMCS Restart of STCW'
satellite went steady shortly afterwards
14:15 AGO ok.
(author on vacation until 1998-09-14)
Wed 1998-09-02 (DoY 245)
14:05 AGO again safemode (but not in previous contacts) (S28)
Next possibility for recovery:
Thu 1998-09-03 (DoY 246)
14:05 AGO ? recovery
...
Thu 1998-09-10 (DoY 253)
Fri 1998-09-11 (DoY 254)
Tests of updated AMCS software at spacecraft simulator at GSOC
Mon 1998-09-14 (DoY 257)
(author back from vacation)
ROSAT is observing according to the timeline.
14:55:00 WHM1 ok; transient at the beginning, steady at the end of the contact
16:30:30 WHM2 safemode; recovery started
19:49:45 WHM4 HRI back in focus, and working
Tue 1998-09-15 (DoY 258)
ROSAT is observing according to the timeline.
14:45:15 WHM1 ok; steady throughout the contact
16:22:00 WHM2 ok; steady throughout the contact (except for short interrupts)
18:01:30 WHM3 ok; steady throughout the contact
19:41:30 WHM4 ok; steady throughout the contact
There is now a (possible) explanation for one particular type of safemode
(CSS3 presence lost after ROSAT night; no return to sun cone possible
within the safemode delay time) (LK):
One of the reaction wheels was close to the saturation threshold
when the satellite left the ROSAT night. The offset between
the actual and nominal spin direction was quite big.
The correction of this situation would have drawn to much current.
The current request is reduced by a factor of 2 in this case,
the resulting torque was not sufficient to return to the
sun cone within the safemode delay time.
A possible solution is the reduction of the spin around the x axis
from 20 Nm to 15 Nm (will be commanded soon), to give more margin for
adjusting the spin after ROSAT nights.
Wed 1998-09-16 (DoY 259)
ROSAT is still observing according to the timeline
(end of last contact: 02:13:26).
Size of Earth block:
The size of the Earth block assumed by the AMCS will be set to 5 deg
after the next safemode (currently: 14.5 deg).
Recent data have shown that stars are tracked and identified far
beyond the 14.5 deg limit.
This change enlarges the radius of the CVZ from 8.5 deg to 18 deg
(a factor of 4.5 square deg in area).
It is yet unclear whether the X-ray data close to the Earth horizon
can really be used: increasing distortion (up to 1 deg) of the guide
star positions has been observed during the ASTROSPAS mission at
angles less then 10 deg above the Earth horizon.
The WFC has not been recovered since the safemode on 1998-09-02.
The reasons were:
- frequent safemodes (roughly every other day)
- bad orbit geometry (Weilheim contacts mainly during ROSAT nights)
- safety reasons (don't damage WFC by incomplete recovery;
WFC recovery needs 2 Weilheim contacts)
14:36:00 WHM1 ok; steady throughout the contact
- start complete recovery of WFC
17:53:30 WHM3 recovery of WFC is finished
- WFC is observing again (HV on)
- AMCS resets of STCW are obviously not accepted by WFC;
'AMCS Restart of STCW enable' has not been sent
(as on DoY 244)
Thu 1998-09-17 (DoY 260)
05:16:47 WPS still ok.
14:27:15 WHM1 ok.
- 'Enable AMCS Restart of STCW' has been commanded
consequently:
- update of actual quaternion by more than 2 deg
- never steady during the contact (only faint stars
in FOV; stars were lost at the end of the contact)
16:05:15 WHM2 ok; steady throughout the contact.
- CSS3 presence threshold set to 7.9 V (previously 7.7 deg)
17:45:15 WHM3 not very stable: frequent changes between steady and transient
19:25:00 WHM4 weird data from WFC; WFC was put into safemode
recovery during the next Weilheim cycle.
CSS3 presence threshold:
CSS1 feedback:
Fri 1998-09-18 (DoY 261)
05:01:48 GDS still ok.
A preliminary analysis of the data of DoY 260 shows that there was
practically no acquisition during the time when the 'AMCS Restart of STCW'
was disabled (1 exception of 3 ks).
The situation changed as soon as 'AMCS Restart of STCW' was enabled.
14:18:30 WHM1 ok.
- Earth block angle was set to 5 deg (previously 14.5 deg)
- recover WFC
15:57:00 WHM2 transient throughout the contact (no stars present;
due to recovery of WFC?)
- reduced value for feedback strength of CSS1
(and CSS3?) information has been sent at the end of the
contact.
16:53:06 ... Safemode triggered during slew (reason: sun in CSS2)
GSOC requested two DSN contacts in order to perform a quick recovery
already during this night (good).
20:39:28 DSN start of recovery
Sat 1998-09-19 (DoY 262)
Successfully recovered. HRI in focus, and switched on.
12:03:30 .... Safemode triggered;
15:48:45 WHM2
15:48:49 2 start of recovery
Sun 1998-09-20 (DoY 263)
00:48:00 .... Safemode triggered during slew (reason: sun in CSS2)
Mon 1998-09-21 (DoY 264)
Currently in safemode.
The revised AMCS software will be uploaded and activated during the
next Weilheim cycle, if possible.
15:32:00 WHM2 Upload new AMCS software:
- correct derivation of angular velocities
- improved defaults for various parameters
- angular momentum around x axis reduced from 20 Nm to 15 Nm
17:12:15 WHM3 Start of recovery
20:31:30 WHM5 Again in safemode (presumably not due to the new software).
Tue 1998-09-22 (DoY 265)
Still in safemode.
12:07:45 WHM1 step 1 of recovery completed.
13:44:15 WHM2 Again in safemode.
- Something is wrong (new software? recovery? new parameter settings?).
- RAM dumps of the new software will be performed during this cycle,
and compared to the simulator contents of the same region.
- No further recovery attempts as long as the reason for these safemodes
is not understood.
- Next possibility for recovery: tomorrow afternoon
(if the problems are understood by then).
Wed 1998-09-23 (DoY 266)
Still in safemode.
The safemode of DoY 265 was due to an error during the recovery,
and not due to an error in the AMCS software; therefore
another recovery will be performed today.
For safety reasons the FI will not be switched on.
11:58:30 WHM1 Step 1 of recovery (?)
16:55:30 WHM4 Satellite is steady at the end of the contact.
18:35:00 WHM5 Not steady throughout the contact (though it should).
Thu 1998-09-24 (DoY 267)
AMCS is in 'degraded mode'; HRI is still off.
11:49:30 WHM1 not in safemode; therefore:
- move HRI into focus, and switch on.
16:47:00 WHM4 HRI quick-look screen shows weird image;
something is wrong with the HRI!
18:26:30 WHM5 Continuously steady at the end of the contact.
HRI image looks strange; electrical values are ok.
Eventually the HRI will be switched off during one of the
next contacts.
Fri 1998-09-25 (DoY 268)
AMCS is in 'safemode'.
No recovery will be performed until the status of the HRI has been
clarified.
Mon 1998-09-28 (DoY 271)
AMCS is in 'safemode'.
During the next Weilheim Cycle the status of the HRI will be checked.
11:14:45 WHM1 Perform UV calibration of HRI:
- Switch off HRI completely.
- Switch on HRI HV.
- Perform UV calibration (starting at HV step 6).
- Increase HRI voltage step by step up to '14'.
- Switch off HRI HV at the end of the contact.
12:54:00 WHM2 Perform UV calibration of HRI:
- Switch on HRI HV.
- Perform UV calibration (starting at HV step 6).
- Increase HRI voltage step by step up to '15'.
- Switch off HRI HV at the end of the contact.
14:34:00 WHM3 Check X-ray performance of HRI:
- Move HRI into focus.
- Switch on HRI HV.
- Increase HRI voltage step by step up to '14'.
- Play around with lower and upper thresholds.
- Switch off HRI HV at the end of the contact.
- Move HRI off focus.
Tue 1998-09-29 (DoY 272)
AMCS is in 'safemode'.
During the next Weilheim Cycle the status checks of the HRI will be continued.
09:30:30 WHM1 Check X-ray performance of HRI (off focus, i.e. background)
- Switch on HRI HV (HV step 14);
observe background count rates, esp. valid/invalid ratio.
- Play around with LL and UL;
observe valid/invalid ratio.
- Reduce HRI HV to step 12; observe valid/invalid ratio.
- Switch off HRI HV at the end of the contact.
11:06:15 WHM2 Observe X-ray performance of HRI during WHM contact:
- Switch on HRI HV (HV step 14); HRI off focus.
- Switch off HRI HV at the end of the contact.
No more checks today.
Wed 1998-09-30 (DoY 273)
AMCS is in 'safemode'.
09:21:00 WHM1 Conditioning (?) of HRI (off focus):
- Switch on HRI HV (HV step 14).
- Send HRI timeline (HRI master resets).
- Set LL=3, UL=0 in order to reduce the HRI countrate
- Do NOT switch off HRI HV at the end of the contact.
10:57:45 WHM2 Conditioning (?) of HRI (continued):
- Move HRI into focus.
- Set LL=0, UL=3 (default).
- Do NOT switch off HRI HV at the end of the contact.
- HRI remains in focus.
:
- Valid (invalid) event rate at 2 (700) cts/s
(somehow healed?)
- similar behaviour as 1 week ago
12:37:30 WHM3 like WHM2 (configuration and behaviour of HRI unchanged)
Operation of the HRI will be continued until the next Weilheim cycle.
Thu 1998-10-01 (DoY 274)
AMCS is in 'safemode'.
HRI is operated nominally, and in focus.
The status of the HRI will be checked by observing Vega (a mere UV source).
Coordinates (equinox 2000.0): (R.A.,Dec.) = (279.234 deg, 38.784 deg)
Current Sun angle: 93.4 deg
Vega is visible during all Weilheim contacts outside the radiation belts.
09:11:45 WHM1 HRI:
- Turn on UV Calibration;
check pattern (esp. if HV overload)
- Move HRI to off position.
AMCS: step 1 of recovery
- careful check of the pointing direction
10:49:30 WHM2 AMCS: step 2 of recovery: cancelled!
- AMCS was put into safemode since it is unclear
whether 2 particular software pacthes are required
for S/W version 11.
HRI (off position):
- low countrates at the beginning of the contact
- therefore UV calibration was switched on
- slowly increasing countrates, which could mean that
the HRI was not saturated at the beginning of the contact
12:29:15 WHM3 AMCS:
Memory load in order to undo a previous memory load.
The status of the AMCS S/W version 11 should now be 'native'.
HRI:
BGR countrate between 10 and 30; image was worse during
the previous contacts.
14:09:00 WHM4 AMCS: step 1 of recovery (see WHM 1).
HRI:
- Quiet at the beginning of the contact.
- HRI was moved into focus and immediately afterwards
out off position; countrate increased to more than
1000 cts/s (in focus) and returned to several
10 cts/s afterwards.
15:48:30 WHM5 AMCS: again in safemode (!)
HRI: same experiment as in WHM4
No further activities today.
Fri 1998-10-02 (DoY 275)
AMCS is in 'safemode'.
HRI is operated nominally, and in off position.
Problems with the recovery yesterday were probably due to an
erroneous determination of the intial sun pointing.
Another recovery will be tried today; the final target will be Vega.
09:03:00 WHM1 HRI: off focus; partly UV calibration
- low background rate before UV calibration (10-20 cts/s)
- UV calibration:
* roughly 700 cts/s
* several dark regions
(caused by parts of the UV filter lying directly
on the channel plates?)
* overall impression: improved status of HRI;
there is still some hope left (?)
AMCS: step 1 of recovery
- careful check of the pointing direction
- strange rotation towards the end of the contact
10:41:00 WHM2 AMCS: again in safemode (same reason as yesterday ...)
HRI: not worse than before.
No further activities during the weekend.
Mon 1998-10-05 (DoY 278)
AMCS is in 'safemode'.
HRI is operated nominally, and in off position.
A recovery will be tried today; the final target will be Vega.
Recoveries cancelled due to computer problems on ground.
No further recovery today.
Tue 1998-10-06 (DoY 279)
AMCS is in 'safemode'.
HRI is operated nominally, and in off position.
A recovery will be tried as soon as a more secure procedure has been
developed and higher priority needs (EUTELSAT) have been satisfied.
No recovery today.
Wed 1998-10-07 (DoY 280)
AMCS is in 'safemode'.
HRI is operated nominally, and in off position.
During future recoveries magnetometer updates of the actual
quaternion will not be allowed until the full
attitude information derived on ground has been commanded.
Furthermore the program used to determine the full attitude
information should be more reliable now.
08:19:30 WHM2 HRI:
- moved HRI to a position further off focus
- low background rates during the contact (at 10 cts/s)
- check whether pattern on HRI changes
if yes: due to external reasons
if no: due to damage of the channel plates
09:59:00 WHM3 AMCS recovery step 1: ok.
11:39:00 WHM- Weilheim antennas are not available during this pass.
13:18:30 WHM4 AMCS recovery step 2: ok
- Earth block during the contact
- a few updates of the actual quaternion
(one by more 10 deg)
14:58:30 WHM5 AMCS recovery step 3: at Vega (!)
- no identification of guide stars at the
beginning of the contact
- acquisition after 'enable WFC Resets by AMCS'
had been sent.
No more actions today.
Thu 1998-10-08 (DoY 281)
AMCS is in 'degraded pointing mode', S/C points to Vega.
HRI is operated nominally, and in off position.
06:33:45 WHM1 AMCS: still in 'degraded pointing mode'
- several updates in RA and Dec during the contact
- never (?) steady during the contact
HRI:
- switched off, moved into focus, switched on for
a few seconds, switched off again, moved to off position,
switched on again
- low countrates at off position
- very high countrates in focus ( > 1000 cts/s )
08:10:45 WHM2 HRI: same procedure as in WHM1; longer exposure on Vega
- no science (80x) frames although the HRI master reset
command was sent several times
- reasonable countrates at off position (< 10 cts/s)
- very high countrates in focus
(<6000 cts/s, then 2500 cts/s HRSTVALEV)
- capacity of onboard tapes was exceeded
- tape dump was performed
- HRI was switched off at the end of the contact
AMCS: never steady (though it should)
09:50:30 WHM3 HRI:
- off and in off position, moved into focus,
HV switched on for several minutes,
switched off and moved to off position
at the end of the contact
- the HRI master reset command had to be sent;
afterwards, science frames (80x) were received
for a few minutes
- countrate was at 6000 cts/s, later at 2500 cts/s
- much more valid (>1000) than invalid (roughly 100) events
- it is not clear whether Vega was really in the FOV
of the HRI (see AMCS)
AMCS: never steady (though it should)
- next target will be WFC Meaty
(RA,Dec) = (247.266 deg, 78.074 deg)
slew scheduled for 11:10 UT.
11:30:30 WHM4 AMCS: on WFC Meaty, and steady during most of the contact
(that means: we know, where we are)
HRI: same game as in WHM3
- countrates at 3500 cts/s, later at >7000 cts/s
- telemetry sync lost during part of the contact
(master reset commanded)
- off focus, and HV off at the end of the contact.
13:10:00 WHM- Weilheim antennas are not available during this pass.
14:50:15 WHM5 AMCS: on WFC Meaty, and steady during most of the contact
HRI: play around with PHA LL and HV
- HV ON and PHA LL = 3
- HV at 14, wait 30 s, to 13, ... to 10, wait 30s, to 0
- off focus at the end of the contact
- countrates: starting with 11000 cts/s, and
dropping to half of the value with each
decrease of the HV
- lost telemtry sync at HV = 11 (no science data)
Fri 1998-10-09 (DoY 282)
AMCS is in 'degraded pointing mode', S/C points to WFC Meaty.
HRI is switched off, and in off position.
08:02:15 WHM2 HRI: play around with PHA LL
- moved into focus; switched on (HV step 14); PHA LL = 0
roughly 4000 cts/s
- increased PHA LL from 0 to 3;
countrate increased (!) to 11000 cts/s
- HRI off at the end of the contact
AMCS: steady from time to time
Switch on HRI during the next ROSAT night, when pointing to the
dark Earth (i.e. the UV darkest region in the sky).
09:42:15 WHM3 AMCS: safemode (!)
11:22:00 WHM4 AMCS: recovery step 1 (successful)
13:01:30 WHM5 AMCS: recovery step 2 (successful)
- commanding guide star catalogue
- enable magnetometer updates
- suspicion: sun sensor updates were disabled
as well before this contact
(large update of the sun angle)
14:42:30 WHM6 AMCS: back to timeline, if everything looks ok.
HRI: HV off, and in off position.
During the weekend the new AMCS software will be tested under
nominal conditions (nominal timeline).
Mon 1998-10-12 (DoY 285)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
No further recovery until safemode data have been analyzed.
Wed 1998-10-14 (DoY 287)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
Observe the brightest X-ray source which is visible during the
Weilheim contacts:
RA = 115.828 deg, Dec = 28.885 deg (Sigma Gem; 8 cts/s in RASS/PSPC)
09:00:30 WHM4 AMCS: recovery step 1 (successful)
10:40:15 WHM5 AMCS: recovery step 2 (successful?)
HRI:
- was moved into focus and switched on
(target: bright Earth!)
- off focus, HV off at the end of the contact
12:10:00 slew to Sigma Gem
12:20:00 WHM6 AMCS:
- still slewing at the beginning of the contact
- steady periods at the end of the contact
HRI:
- moved into focus; HV was switched on
- countrates at 2500 cts/s
- source was not visible when satellite was steady
- HV off, moved to off position at the end of the contact
Thu 1998-10-15 (DoY 288)
AMCS is in 'degraded pointing mode', S/C points to Sigma Gem'.
HRI is switched off, and in off position.
Plans for today:
- HRI: move into focus and switch on for a full orbit
(between to WHM contacts); get Sigma Gem,
Dark and Bright Earth data.
- AMCS: go back to nominal timeline after the WHM cycle;
disable STCW stars shortly (? 30 s) before and shortly (? 90 s)
after the slew start times (workaround for a bug in the
AMCS software which 'disrupts' the timeline).
08:52:15 WHM4 AMCS: steady during most of the contact
HRI:
- move into focus; switch on HV
- countrates at 5000 cts/s (HRSTVALEV),
or a few 100 cts/s (valid/invalid events)
- HRI remains in focus and switched on until
the next contact
10:31:45 WHM5 HRI:
- played around with PHA LL (0, then 1, then 3)
- sync lost atsome point; fixed by HRI master reset
- switched off and moved to off position at the
end of the contact.
AMCS:
- no star control at the beginning of the contact
- as soon as stars were identified, a continuous
increase of the wobble amplitude in x direction
was observed (starting at 3 arcmin,
finally at 10 arcmin)
12:11:45 WHM6 HRI: off; in out-of-focus position
AMCS:
- change (increase) scaling factor from CSS1 to CSS3;
should avoid halt at the rim of the sun cone as
observed during the safemode on 1998-10-10
- resend feedback parameter from STCW to AMCS
(in order to make sure that the correct value is used)
(should result in smaller wobble amplitudes;
currently at 10 arcmin)
- return to timeline; disable stars from STCW
shortly before and shortly after slew start times
Fri 1998-10-16 (DoY 289)
AMCS is in 'degraded pointing mode', S/C is observing according to timeline.
HRI is switched off, and in off position.
Plans for today:
- HRI: play around with HV
- AMCS: continue with timeline
07:03:45 WHM3 HRI:
- move into focus; switch on HV
- reduce HV to step 12, then to step 10;
countrate decreases from 6000 cts/s to
several 100 cts/s
- HRI is operated in focus until the next WHM contact
08:43:45 WHM4 HRI:
- increase HV to step 11
countrate increases from several 100 cts/s to
about 1500 100 cts/s
- HRI is operated at this HV until the next WHM contact
10:23:15 WHM5 HRI:
- increase HV to step 12
12:03:45 WHM6 HRI:
- HRI not in sync
- switched off HV; moved to off position
Timeline had to be deleted up to the end of the next Weilheim cycle
since 'security slews' had not been implemented; continuation of the
timeline on 1998-10-17 at 12:18:40 UT.
Mon 1998-10-19 (DoY 292)
AMCS is in 'safemode' (since Sunday morning).
HRI is switched off, and in off position.
No recovery until the reasons for the safemode have been analyzed.
Tue 1998-10-20 (DoY 293)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
Still no data from the last safemode (DTS problems), therefore no recovery.
Thu 1998-10-22 (DoY 295)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
Today we will try to acquire Cyg X-1, a bright, hard X-ray source:
R.A. = 299.5913 deg
Dec = 35.1990 deg
PSPC countrate 61 cts/s, ROSAT hardness ratio 0.98 (RASS)
Visible over Weilheim, shortly after Earth block
Within CVZ sometime next week
Observing window: 1998-10-10, 21h to 1998-12-02, 07h
04:33:30 WHM3 AMCS: recovery step 1 (successful)
06:13:30 WHM4 AMCS: recovery step 2 (successful)
07:53:00 WHM5 AMCS: no action due to computer problems on ground
09:33:00 WHM6 AMCS: recovery step 3 (start slew to Cyg X-1) (ok)
14:16:53 WPS AMCS: steady; amplitude increasing from <2 to >10 arcmin
Fri 1998-10-23 (DoY 296)
AMCS is in 'degraded pointing mode'; S/C is pointing to Cyg X-1.
HRI is switched off, and in off position.
Today we will try to detect Cyg X-1 with the HRI.
Due to instabilities of the AMCS Cyg X-1 will move by +-10 arcmin
around the detector center, which should allow to sample the
sensitivity of various regions of the detector.
06:05:00 WHM4 AMCS:
- switching between steady and transient
- amplitude about 10 arcmin, period several 10 s
07:44:30 WHM5 HRI:
- moved into focus; switched on to HV step 14, then 11
- PHA LL=0, UL=3
- about 10000 cts/s (slightly decreasing),
1000 cts/s at step 11
- practically no photons in the central region of the HRI
along the line where Cyg X-1 is expected;
most photons are 'generated' at the rim of the HRI.
Now I am absolutely convinced that the HRI is
definitely lost and can't be used for anything.
Between WHM5 and WHM6 the HV is increased by one step every 10 minutes:
HV at 10/11/12/13/14/11 at UT 07:52/08:02/08:12/08:36/08:46/08:56
09:24:45 WHM6 HRI:
- switched off; moved to off position
AMCS:
- usual behaviour (swinging by +-10 arcmin or more)
Mon 1998-10-26 (DoY 299)
AMCS is in 'degraded pointing mode'; S/C is pointing to Cyg X-1.
HRI is switched off, and in off position.
07:19:00 WHM5 AMCS: unchanged
(steady and transient periods; amplitude 10 arcmin)
13:42:47 WPS AMCS:
- steady and transient at the beginning of the contact
- continuously transient at the end of the contact
Tue 1998-10-27 (DoY 300)
AMCS is in 'degraded pointing mode'; S/C is pointing to Cyg X-1.
HRI is switched off, and in off position.
07:10:45 WHM5 AMCS:
- still on Cyg X-1
- steady and transient periods
13:34:19 WPS AMCS:
- is on timeline (not requested by anybody)
- Earth block during the contact
20:04:45 --- AMCS safemode triggered.
Wed 1998-10-28 (DoY 301)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
Thu 1998-10-29 (DoY 302)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
The long delay times between star measurement and star identification
cause large wobble amplitudes (10 arcmin).
We now try to derive angular velocities again from the sun sensor,
and disable the STCW angular velocities.
The corresponding checks and commands will be done and sent this
afternoon during the Wallops contact.
Furthermore, star identification will be disabled during ROSAT nights;
this should help to reduce the large nutation cones observed
during ROSAT nights, and to avoid further safemodes
(on the cost of observing time).
A recovery is scheduled for tomorrow morning.
11:37:54 WPS AMCS:
- check allowed time difference range for
STCW angular velocities (should be ?2s-10s): ok
- command new time difference range (2s-3s),
thus disabling STCW angular velocities: ok
Fri 1998-10-30 (DoY 303)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
05:05:30 WHM5 AMCS: recovery step 1 (ok)
06:45:30 WHM6 AMCS: recovery step 2 (ok)
- remain on arbitrary target (ok)
(R.A.,Dec) = (329 deg, -60 deg)
(advantage: sun angle == 90 deg)
- Earth block during contact
11:29:19 WPS AMCS: not in safemode
For some reason the sunsensor update threshold was set to 10 deg, and
not at 50 deg as intended. Several safemodes can be explained
by this fact (those for which the satellite did not
return to the allowed sun cone after a ROSAT night).
The correct value has been commanded today.
Mon 1998-11-02 (DoY 306)
AMCS is in 'degraded pointing mode';
S/C is pointing to an arbitrary (recovery) target.
HRI is switched off, and in off position.
04:40:00 WHM5 AMCS: not in safemode
11:03:30 WPS AMCS: back in safemode
According to GSOC the battery was in a bad state on Friday last week
(although ROSAT was in safemode since Tuesday evening).
Furthermore a workaround for disabling STCW information during night
will not be available before tomorrow.
Therefore no recovery will be performed during the next Weilheim cycle.
23:50:00 TT HRI: UV calibration sequence (off focus)
DoY::hh:mm:ss HV LL UL
----------------------------------
306::23:50:00 10 0 3
52 10 1 3
54 10 2 3
56 10 3 3
58 10 3 0
307::00:00:00 11 0 3
02 11 1 3
04 11 2 3
06 11 3 3
08 11 3 0
00:10:00 12 0 3
12 12 1 3
14 12 2 3
16 12 3 3
18 12 3 0
(belt)
00:30:00 13 0 3
32 13 1 3
34 13 2 3
36 13 3 3
38 13 3 0
00:40:02 0 3 0
Tue 1998-11-03 (DoY 307)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
The commands for the upper SS update threshold (50 deg) and the
upper value for the allowed time difference between two star measurements
(3 s) will be sent AFTER the next recovery, thus they will not be
overwritten.
The workaround for disabling the STCW during ROSAT night should be available
by tomorrow.
Wed 1998-11-04 (DoY 308)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
The next recovery will not be performed before Friday evening
(currently all WHM contacts occur during night, and DSN contacts
are not available due to Space Shuttle flight).
Fri 1998-11-06 (DoY 310)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
21:58 CNB AMCS: recovery step 1 (?)
22:58:00 WHM3 AMCS: recovery step 2 (?)
The sun pointing target will be continuously observed during the weekend.
Checks to be done on Monday:
1) Are there big nutation cones during the ROSAT night, although
STCW control is disabled during night?
2) If there are big nutation cone:
Does the pointing direction return to the sun cone
within the safemode delay time (600 s)?
Assumptions:
1) STCW control is disabled during night
(by commands automatically generated by ROSMAC).
2) Angular velocities are derived from the sun (only during day),
and not from the STCW information
(by the 10 s to 3 s reduction of the corresponding upper threshold)
3) The SS update threshold has been set to 50 deg.
Mon 1998-11-09 (DoY 313)
AMCS is in 'degraded pointing mode';
S/C is pointing to an arbitrary (recovery) target.
HRI is switched off, and in off position.
Analysis of the weekend data:
- Stars were never identified; checks / possible reasons:
* Resets are sent by the AMCS, and accepted by STCW.
* Alternating STCW source flag (no STCW control during ROSAT night)
was in princip commanded, though it is not yet clear, whether
the tiny details were done correctly.
* Another explanation would be that the nominal roll angle around
the sun direction does not correspond to the true angle
(is off by more than ?10 deg, the upper threshold for
magnetometer updates).
- Big sun cone offsets are built up during the ROSAT nights.
The return into the sun cone after the ROSAT night seems to work
fine now (good).
As it turned out, nominal and actual pointing direction did not match
by more than specified by the upper magnetometer update threshold
(one reason for this could be that the magnetometer updates
were not enabled at the end of the recovery;
another reason could be that the roll angle around the sun axis
again was not determined correctly during the recovery).
?14:00 AGO AMCS:
- s/c put into safemode for a short period (reason: ROSMAC)
- step 1 of recovery
19:14:15 WHM1 AMCS:
- step 2 of recovery
20:52:45 WHM2 AMCS:
- slew to SN 1987A (RA=83.867deg, Dec=-69.270deg)
purpose: check whether targets in the LMC
can be acquired
Tue 1998-11-10 (DoY 314)
AMCS is in 'degraded pointing mode'; S/C is pointing to SN 1987A.
HRI is switched off, and in off position.
The recovery target and SN 1987A were acquired without problems
last night. The wobble amplitudes are at 3 arcmin (instead of
10 arcmin when angular velocities were derived from the stars;
the velocities are now derived from the sun sensors!).
Today we will slew to Cyg X-1; we will check by a few offset pointings
whether Cyg X-1 can be detected in the corners of the HRI,
where the UV calibrations showed a similar behaviour as
before the damage.
Preliminary Cyg X-1 observing program:
Time duration HV LL UL target Cyg X-1 (hopefully) at
UT s detector coordinates
----------------------------------------------------------------
21:45 1200 14 3 0 Cyg X-1 pos 1 905, 905
22:05 1200 14 0 3 Cyg X-1 pos 1
23:20 1200 14 0 3 Cyg X-1 pos 2 3190, 905
23:40 1200 14 3 0 Cyg X-1 pos 2
01:00 1200 14 3 0 Cyg X-1 pos 3 905,3190
01:20 1200 14 0 3 Cyg X-1 pos 3
Detector coordinates: as transmitted in telemetry
(1 pixel is 0.557 arcsec; center at 2048,2048;
origin is at the upper left corner in my colour images)
After the Weilheim cycle we return to the nominal timeline.
STCW control will be disabled during slews, but not during nights
(there should be no longer be a problem with STCW control during
night, since the s/c returns now reliably into the sun cone after
the nights).
Wed 1998-11-11 (DoY 315)
AMCS is in 'degraded pointing mode'; S/C should be on nominal timeline.
HRI is switched off, and in off position.
During the next Weilheim cycle we will try to fully recover the WFC,
in order to check for the first time after the sun pointing on 1998-Sep-20
whether there was a damage of the WFC.
Thu 1998-11-12 (DoY 316)
AMCS is in 'degraded pointing mode'; S/C should be on nominal timeline.
HRI is switched off, and in off position.
WFC is operated nominally.
07:58:36 WPS AMCS: in safemode!
Recovery not before tomorrow evening (no sun during WHM cycle today).
17:12:45 WHM1 AMCS:
- check contents of RAM word 0C06x
(nominator of CSS1/CSS3 scaling);
* should be 5332x, corresponding to a scaling value
of 1.298, if last recovery was done correctly
* analysis of DoY 313 data led to the conclusion
that the scaling factor was wrong after the last
recovery, leading to scaled small positive
values for CSS3 from large negative values from CSS1.
* value is ok (checked).
Fri 1998-11-13 (DoY 317)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
WFC is in safemode.
Recovery will be tried using a DSN contact before WHM5.
STCW control will be disabled during slew and night
(during night STCW control obviously causes
large nutation cones which in turn lead to safemodes).
23:28:54 WPS? AMCS: recovery step 1
01:18:15 WHM6 AMCS: recovery step 2
Recovery was ok (targets were acquired).
Sat 1998-11-14 (DoY 318)
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline.
HRI is switched off, and in off position.
WFC is in safemode.
13:02:26 --- AMCS: safemode triggered
Mon 1998-11-16 (DoY 320)
AMCS is in safemode.
HRI is switched off, and in off position.
WFC is in safemode.
A recovery will be tried during the next WHM cycle; final target
will be (331 deg, -22 deg) (opposite to radiant of Leonides
meteor shower); no return to timeline before tomorrow night.
Tue 1998-11-17 (DoY 321)
AMCS is in 'degraded pointing mode'; S/C is pointing to 'Anti-Leonides'
HRI is switched off, and in off position.
WFC is in safemode.
Return to timeline after the next Weilheim cycle this evening.
Wed 1998-11-18 (DoY 322)
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline.
HRI is switched off, and in off position.
WFC is in safemode.
14:01:23 --- AMCS: safemode triggered
- target acquired before ROSAT night
- large nutation cone (30 deg radius) starting at
the transition to the ROSAT night
- CSS3 nearly constant at -4 V after the ROSAT night
several attitude updates every 120 s, which are
immediately corrected afterwards.
Thu 1998-11-19 (DoY 323)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
WFC is in safemode.
16:07:45 WHM1 AMCS: recovery step 1
Return to timeline at the end of this Weilheim cycle.
Fri 1998-11-20 (DoY 324)
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline.
HRI is switched off, and in off position.
WFC is in safemode.
A procedure 'ram_test.ins' has been developed which dumps the contents
of certain AMCS parameters. In future, this procedure will be commanded
every day during WHM1, and after a Safemode or a recovery.
Thus a regular log of important AMCS parameters will be available
for a sound analysis of AMCS problems.
14:23:15 WHM1 AMCS:
- not in safemode
- 'ram_test.ins' was sent for the first time
Mon 1998-11-23 (DoY 327)
No safemode during the weekend.
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline.
HRI is switched off, and in off position.
WFC is in safemode.
The WFC will be recovered during the next Weilheim cycle,
and 'Meaty' will be observed according to request of WFC team.
Tue 1998-11-24 (DoY 328)
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline ('Meaty').
HRI is switched off, and in off position.
WFC is operated nominally.
Next we will try one of the WFC final targets
(ROR 180320, target 'RE1149', a CV,
at R.A. = 177.4814 deg, Dec. = 28.7524 deg; filter S1A).
Wed 1998-11-25 (DoY 329)
AMCS is in 'degraded pointing mode'; S/C is pointed to 'RE1149'.
HRI is switched off, and in off position.
WFC is operated nominally.
Fri 1998-11-27 (DoY 331)
AMCS is in 'degraded pointing mode'; S/C is pointed to 'RE1149'.
HRI is switched off, and in off position.
WFC is operated nominally.
Next Sunday or Monday the CSS1/CSS3 scaling factor will be restored
to its old value. The intention is to avoid cases where the
pointing direction is trapped at the rim of the sun cone
at the transition from CSS1 to CSS3 control.
Probably on Monday we will return to the timeline.
Sat 1998-11-28 (DoY 332)
AMCS is in 'degraded pointing mode'; S/C is pointed to 'RE1149'.
HRI is switched off, and in off position.
WFC is operated nominally.
15:35:52 ---- AMCS:
safemode triggered only 30 s after end of ROSAT night (!)
Mon 1998-11-30 (DoY 334)
AMCS is in 'safemode'.
HRI is switched off, and in off position.
WFC is in safemode.
14:32:00 WHM3 AMCS recovery step 1
- not completed since 'initial attitude not available'
(due to alignment of magnetic field and sun direction?)
16:12:00 WHM4 AMCS recovery step 1 (retry)
- seems to be ok
Tue 1998-12-01 (DoY 335)
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline.
HRI is switched off, and in off position.
WFC is in safemode.
Wed 1998-12-02 (DoY 336)
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline.
HRI is switched off, and in off position.
WFC is in safemode.
10:14:42 ---- AMCS: safemode triggered
roughly 60 s after end of ROSAT night;
(due to missing presence in CSS3)
12:35:15 WHM2 AMCS recovery step 1 (ok)
14:15:15 WHM3 AMCS recovery step 2
problems at GSOC (according to ATOR)
15:55:00 WHM4 AMCS recovery step 2 repeated
17:34:30 WHM5 AMCS recovery complete; 'steady' during the contact
Thu 1998-12-03 (DoY 337)
AMCS is in 'degraded pointing mode'; S/C is on nominal timeline.
HRI is switched off, and in off position.
WFC is in safemode.
eof