Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/institute/org/telescopes/AOAdata.pdf Дата изменения: Wed Jun 8 20:37:15 2005 Дата индексирования: Sat Dec 22 12:56:35 2007 Кодировка: Поисковые слова: comet tail


Since 2002 we've detected anomalously high g yro biases - occur during terminator crossings - magnitude of the bias has increased steadily - 4 arcsec/hr after SM3B to a current -40 arcsec/hr - predominantly seen in V3 translation - event typically ~5-10 arcsec in <10 minutes This anomalous motion has been virtual, only being inferred from g yro data; during Fine Lock obser vations the field is held fixed by the FGSs As the problem worsens, it can eventually impact the FGSs ability to acquire or re-acquire guidestars. HSTAR 9819 recently found to be caused by the AOA


The RSUs are accurately recording a local motion (i.e. equipment shelf movement with respect to the OTA and rest of vehicle) There is no motion local to the RSU and they are recording a vehicle motion. Since there is no drift in science data this would mean the OTA FOV is shifting and the FGSs are driving the vehicle to hold the guidestars at fixed FGS XY There is some problem in the control law involving both RSU and FGS data The RSU data is not correct for other reasons


The test was not to represent a risk to the vehicle (e.g. cycling RSUs) Test was designed to deter mine the involvement of the OTA str ucture in the AOA. It should answer the question of the amount of anomalous motion attributable to the OTA - obtained science data and measured off-axis PSF aberrations - aberrations will be expressed in terms of Secondary Mirror tilts & decenters - magnitude and direction of image shifts resulting from the calculated SM motions will be compared to the obser ved motion, also directly quantified by the test.


Orbit 1 - Baseline and to establish known g yro bias

- FGS fine lock on previously used guidestars - 100 TRANS mode scans with FGS1 on target star known to be single to FGS

(aberration info) - 50 ACS/HRC custom sub-array exposures in parallel every 90 seconds. Target known to be single to HRC (aberration and position info) - 68 NICMOS/NIC1 multi-accum exposures in parallel every 30 seconds for maximum time coverage (aberration and position info) - 2 WFPC2/WF3 exposures at the end to better establish roll baseline

Orbit 2 - Measure position drift to directly obser ve AOA

- Drop to Gyro Track - FGS POS mode astrometry (position info) - 48 ACS/HRC exposures every 90 seconds (secondary aberration and position
info) - 5 WFPC2/WF3 exposures to monitor relative roll changes


12.7 9.8 11.0 6.2 10.6 12.7 11.5 11.2 12 12.3 12.4 12.4 11.1 10.

11.9

12.4 11.2 9.6 12.4 .3 7.1 7.3 7.3 7.3 12.6 8.0 11.3 9.9 12.6 12.9 12.4 12.0 13.0 10.8 12.6 12.4 12.3 11.1 12.4 12.4 12.111.7 12.5 10.9 11.0 12.5 10.7 11.5 10.5 10.1 10.3 10.3 12.9 12.3 12.2 11.9 10.4 12.2 8.813.3 6.8 7.4 7.5 7.5 12.3 12.1 13.4 10.9 12.7 11.6 12.7 13.0 12.0 12.4 11.8 12.8 12.6 12.3 11.5 11.8 12.4 13.2 11.4 12.3 12.2 12.9 12.1 12.5 13.0 12.9 12.3 12.1 12.3 12.6 11.3 10.0 10.0 9.6 11.1 11.7 11.3 8.210.9 11.7 9.5 9.5 7.9 12.6 9.6 11.0 10.3 11.5 11.4 11.2 11.3 11.3 9.2 8.8 9.2 9.2 9.5 9.8 9.4 10.4 12.8 11.112.8 9.3 12.5 11.4 11.1 11.1 12.6 12.1 12.5 12.3 12.9 11.9 11.4 13.5 12.7 11.9 8.0 8.8 8.8 13.9 13.3 12.7 12.0 10.8 10.8 10.8 10.8 10.9 11.0 9.9 11.2 13.0 12.1 12.5 12.5 11.6 11.1 10.8 8.9 8.1 8.9 8.9 8.9 7.8 7.8 7.7 8.4 8.5 8.5 11.3 11.5 10.7 11.0 13.3 12.8 12 1 11.4 11.0 10.4 13.9 9.8 9.7 11.4 11.9 12 13.0 1 8.9 8.9 10.7 12.7 13.0 11.5 12.1 12.5 12.5 12.4 1 13 13.6 12.6 11.9 12.6 12.4 11.9 10.5 10.8 14.2 10.4 11.6 12.5 13.0 8.7 12.8 11.4 11.1

11.6 11.6 11.1 11.6

14.0 7.8 6.8 7.8 13

12.5 12.4

12.1 13.2 13.4

11


Observed Motion of Target in HRC during gyro-guiding Orbit 2
750

700

650

HRC Y pixels (0.025 arcsec/pix)

V3
600

-V2
550

500

450

400

350 350 400 450 500 550 600 650 700 750

HRC X pixels (0.028 arcsec/pix)


Observed Motion of Target in HRC during gyro-guiding Orbit 2
4.00

3.00

2.00

arcseconds displacement

V2 1.00 V3

0.00

-1.00

-2.00

-3.00

-4.00 18.8 18.9 19 19.1 19.2 19.3 19.4 19.5 19.6 19.7 19.8 19.9 20 20.1 20.2

Day 142 hours


ACS/HRC AOA Test: Focus Measurements
0.00

-0.50

-1.00

Focus (in microns @ Secondary Mirror)

-1.50

-2.00

-2.50

-3.00

-3.50

-4.00

-4.50

AOA Test (Orbit 1) AOA Test (Orbit 2)

-5.00

17.00

17.25

17.50

17.75

18.00

18.25

18.50

18.75

19.00

19.25

19.50

19.75

20.00

20.25

20.50

Hours (Day 2005.142)


ACS/HRC AOA Test: X-Coma v. Time
0.000 -0.001 -0.002 -0.003 -0.004 0.003 0.002 0.001 0.000 -0.001

ACS/HRC AOA Test: Y-Coma v. Time

X-Coma

Y-Coma

-0.005 -0.006 -0.007 -0.008 -0.009 -0.010 17.00 AOA Test (Orbit 1) AOA Test (Orbit 2)

-0.002 -0.003 -0.004 -0.005 -0.006 -0.007 17.00 AOA Test (Orbit 1) AOA Test (Orbit 2)

17.25

17.50

17.75

18.00

18.25

18.50

18.75

19.00

19.25

19.50

19.75

20.00

20.25

20.50

17.25

17.50

17.75

18.00

18.25

18.50

18.75

19.00

19.25

19.50

19.75

20.00

20.25

20.50

Hours (Day 2005.142)

Hours (Day 2005.142)

ACS/HRC AOA Test: X-Astigmatism v. Time
0.012 0.011 0.010 0.009 0.008 0.007 0.006 0.005 0.012 0.011 0.010 0.009 0.008 0.007 0.006 0.005 AOA Test (Orbit 1) AOA Test (Orbit 2)

ACS/HRC AOA Test: Y-Astigmatism v. Time

X-Astigmatism

0.004 0.003 0.002 0.001 0.000 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 17.00 17.25 17.50 17.75 18.00 18.25 18.50 18.75 19.00 19.25 19.50 19.75 20.00 20.25 20.50 AOA Test (Orbit 1) AOA Test (Orbit 2)

Y-Astigmatism

0.004 0.003 0.002 0.001 0.000 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 17.00 17.25 17.50 17.75 18.00 18.25 18.50 18.75 19.00 19.25 19.50 19.75 20.00 20.25 20.50

Hours (Day 2005.142)

Hours (Day 2005.142)


!"#$%&"'!(!')*+,-'./!+,0123,0+2'45'6789+':;<=
0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.012 0.011

!"#$%&"'!(!')*+,-'./!+,0123,0+2'45'6/"723

AOA Test (Orbit 1) AOA Test (Orbit 2)

0.01 0.009 0.008 0.007 0.006

AOA Test (Orbit 1) AOA Test (Orbit 2)

./!+,0123,0+2

./!+,0123,0+2

0.005 0.004 0.003 0.002 0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 -0.025 -0.024 -0.023 -0.022 -0.021 -0.020 -0.019 -0.018 -0.017 -0.016 -0.015 -0.014 -0.013 -0.012 -0.011 -0.010 -0.009 -0.008 -0.007 -0.006 -0.005 -0.004 -0.003

0.005 0.004 0.003 0.002 0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 -0.007 -0.006 -0.005 -0.004 -0.003 -0.002 -0.001 0.000 0.001 0.002 0.003

6789+':;<=

6/"723

!"#$%&"'!(!')*+,-'./"012'34'5067+'89:;
0 -0.001 -0.002 -0.003 -0.004 0.003 0.002 0.001 0 -0.001

!"#$%&"'!(!')*+,-'./"012'34'5/"012
0.003 0.002 0.001 0 -0.001

!"#$%&"'!(!')*+,-'./"012'34'5067+'89:;
0.012 0.011

!"#$%&"'!(!')*+,-'./!+,0123,0+2'45'./"623

AOA Test (Orbit 1) AOA Test (Orbit 2)

AOA Test (Orbit 1) AOA Test (Orbit 2)

0.01 0.009 0.008 0.007 0.006

AOA Test (Orbit 1) AOA Test (Orbit 2)

./!+,0123,0+2

0.005 0.004 0.003 0.002 0.001 0

./"012

./"012

-0.005 -0.006 -0.007 -0.008 -0.009 -0.01 -0.025 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 -0.011 -0.010 -0.009 -0.008 -0.007 -0.006 -0.005 -0.004 -0.003 -0.002 -0.001 -0.024 -0.023 -0.022 -0.021 -0.020 -0.019 -0.018 -0.017 -0.016 -0.015 -0.014 -0.013 -0.012 -0.011 -0.010 -0.009 -0.008 -0.007 -0.006 -0.005 -0.004 -0.003

-0.002 -0.003 -0.004 -0.005 -0.006 -0.007 -0.011 -0.010 -0.009 -0.008 -0.007 -0.006 -0.005 -0.004 -0.003 -0.002 -0.001

./"012

-0.002 -0.003 -0.004

-0.001 -0.002 -0.003 -0.004 -0.005

AOA Test (Orbit 1) AOA Test (Orbit 2)

-0.005 -0.006 -0.007 -0.025 -0.024 -0.023 -0.022 -0.021 -0.020 -0.019 -0.018 -0.017 -0.016 -0.015 -0.014 -0.013 -0.012 -0.011 -0.010 -0.009 -0.008 -0.007 -0.006 -0.005 -0.004 -0.003

-0.006 -0.007 -0.006 -0.005 -0.004 -0.003 -0.002 -0.001 0.000 0.001 0.002 0.003

5067+'89:;

5/"012

5067+'89:;

./"623

!"#$%&"'!(!')*+,-'./!+,0123,0+2'45'./"623
0.012

!"#$%&"'!(!')*+,-'./!+,0123,0+2'45'6/!+,0123,0+2
0.012 0.011 0.01 0.009 0.008 0.007 0.006

!"#$%&"'!(!')*+,-'./!+,0123,0+2'45'6/"723

AOA Test (Orbit 1) AOA Test (Orbit 2)

0.011 0.01 0.009 0.008 0.007 0.006

AOA Test (Orbit 1) AOA Test (Orbit 2)

./!+,0123,0+2

./!+,0123,0+2

0.004 0.003 0.002 0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 -0.006 -0.005 -0.004 -0.003 -0.002 -0.001 0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.010 0.011 0.012

./!+,0123,0+2
AOA Test (Orbit 1) AOA Test (Orbit 2)

0.005

0.005 0.004 0.003 0.002 0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 -0.011 -0.010 -0.009 -0.008 -0.007 -0.006 -0.005 -0.004 -0.003 -0.002 -0.001

./"623

6/!+,0123,0+2

6/"723