HST
MOSES
SMOV4 REQUIREMENTS REVIEW
21 MAR. 2007
1
SMOV4 REQUIREMENTS
REVIEW
AGENDA
ITEM
LEAD
HST
MOSES
TIME (min)
PAGE
=======
=====
=======
====================
Intro
Carl Biagetti, Rick Burley
10
2
PCS
Dan Smith
10
10
TCS
Josh Abel
5
13
OTA/FGS
Matt Lallo, Ed Nelan, Art Bradley
15
14
WFC3
John MacKenty
20
22
COS
Alessandra Aloisi
20
33
ACS
Kailash Sahu
20
52
STIS
Charles Proffitt
20
60
NICMOS/NCS
Tommy Wiklind
20
72
ERO
Carl Biagetti
1
81
Closing
Carl Biagetti, Rick Burley
9
=======
21 Mar. 2007
2h30m
2
SMOV4 Level III Requirements
Document -- SMR 4029, App. L
HST
MOSES
ITEM
REQUIREMENTS SEC.
=========
===================
WFC3
L.10.4.1
COS
L.10.4.2
ACS
L.10.4.3
NICMOS/ NCS L.10.4.4
STIS
L.10.4.5
ERO
L.10.4.6
OTA/FGS
L.10.4.7
PCS
L.10.4.8
DMS *
L.10.4.9
I&C *
L.10.4.10
SIC&DH *
L.10.4.11
S&M *
L.10.4.12
TCS
L.10.4.13
EPS *
L.10.4.14
* No SMOV requirements identified.
21 Mar. 2007
3
SMOV4 Planning Schedule
for Sep 2008 Launch
Start*
======
Oct06
End*
======
Mar07
21Mar07
Mar07
Jun08
Oct07
Activity
========== ============================
Requirements Update
SMOV Planning
SMOV Project Review
Aug08
Aug08
13Aug08
SMOV Implementation Phase
- Proposal generation/iteration
- Special Commanding Development (ASAP)
- ERO program
Test Calendar/SMS generation
GSFC Launch Readiness (FRR)
Aug08
STScI SM4/SMOV Readiness Review
11Sep08
19Sep08
MOSES
SMOV Requirements Review
26Oct07
Oct07
HST
SM4 Launch
~Jan09
Apr09
* Exact dates are TBD
SMOV4
SMOV4 Closure Review
21 Mar. 2007
4
Current SM4 Plans
HST
MOSES
•
•
•
•
•
•
•
•
•
•
WFC3 is installed (in place of WFPC2)
COS is installed (in place of COSTAR)
FGS3R replaces FGS3
STIS is repaired
All six gyros are replaced
All six batteries are replaced
Overvoltage Protection (OVP) kit is installed
Optical Control Electronics (OCE) is connected
NOBL is installed on Bays 5, 7, 8
Soft Capture Mechanism (SCM) is installed
– In parallel with EVAs
•
•
Reboost
Release on Flight Day 9 (Sep. 19)
•
Note: ASCS, which was to be attached to STIS & COS, is no longer manifested.
21 Mar. 2007
5
SMOV4 Concept
GENERIC SMOV GOALS
HST
MOSES
• Timely recommissioning of the Observatory for science
operations
– Commission newly installed science instruments
– Recommission existing science instruments
– Recommission restored science instruments
• Recommission Observatory systems for normal
operations
• Validation of other on-orbit replacements & installations
• Early Release Observations
• Demonstrate upgraded science capabilities to astronomical
community and general public
21 Mar. 2007
6
SMOV4 CONCEPT
ASSUMPTIONS AND INITIAL CONDITIONS AT
RELEASE
•
HST
MOSES
SPACECRAFT SUBSYSTEMS
–
PCS
•
6 new gyros (uncalibrated)
•
•
4-gyro complement at least through gyro calibration activity
CVZ pointing (North or South TBD) for Bright Earth Avoidance (BEA)
–
–
EPS
•
–
New batteries on line
TCS
•
–
NOBL installed in Bays 5,7,8
OTA
•
Normal operating mode
–
–
–
Heaters Off
One new (uncalibrated) FGS
DMS
•
•
•
–
May entail some slewing restrictions
DMU Side A
HST486 in VSS mode
SSRs configured for normal science ops
I&C
•
•
Normal TDRS configuration
Unrestricted SSAT use
21 Mar. 2007
7
SMOV4 CONCEPT
HST
ASSUMPTIONS AND INITIAL CONDITIONS AT
RELEASE (Cont’d)
•
MOSES
Science Instruments
–
–
–
–
COS in Safe
WFC3 in Safe
ACS in Safe
NICMOS in Safe
• NCC off
• ESM in Safe
– STIS (restored) in Safe
– FGSs in Operate
•
Requirements Assumptions
– ACS SMOV requirements assume fully restored ACS
• Final requirements will be a function of specific repair mode
– OTA SMOV requirements assume only ACS/SBC
– These two assumptions result in the least amount of requirements
rework once a course of action is known
21 Mar. 2007
8
SMOV4 CONCEPT
HST
OPERATIONS DRIVERS/RESTRICTIONS
MOSES
• Bright Earth Avoidance (BEA)
– 30 days starting at Release
• Driven by WFC3 CARD
• Possible ramp-up of BE exposure starting at 21 days
– End-BEA UV Check to be performed using TBD
• NCS/NICMOS Cooldown
– No ACS/STIS/FGS pre-requisites
– NCS Idle/Cooldown testing not a SMOV requirement
• Pending specifics of SI configuration and the HST power
budget post-SM4
21 Mar. 2007
9
PCS Verification
L.10.4.8
HST
MOSES
• L.10.4.8.1 Following release, the HST Pointing Control System will be
returned to normal operations for SMOV with four gyros in the active
control loop, (no shadow mode). A fine attitude reference will be
uplinked to the spacecraft and the spacecraft will be maneuvered to
point to the BEA attitude. The gyro biases will be determined and
maintained to within 0.014 arc-seconds per second to allow successful
guide star acquisition at the transition to the Science SMS.
• L.10.4.8.2 If any gyros are changed out, the gyro to FHST calibration
shall be updated to an accuracy that reduces the attitude error following
a vehicle maneuver to one arc-second per degree of slew or less. This
calibration will be performed immediately after the end of the BEA
period. Until then, history has shown slew miss-distances of about six
arc-seconds per degree of slew.
• L.10.4.8.3 The PCS shall acquire guide stars in fine lock.
21 Mar. 2007
10
PCS Verification
L.10.4.8 (cont.)
HST
MOSES
•
L.10.4.8.4 Once guide star acquisitions have begun, 2-FGS acquisitions will be
scheduled such that the HST486 on-board gyro bias update algorithm will
maintain the gyro drift rate bias to within 0.005 arc-seconds per second.
•
L.10.4.8.5 The vehicle jitter during periods of gyro hold shall be measured.
•
L.10.4.8.6 Perform a Vehicle Disturbance Test (VDT) to characterize HST lineof-sight jitter, structural dynamic responses, and disturbance sources. The VDT
is a passive test (not a forced response test) using a low-bandwidth attitude
control law during gyro-hold with the rate gyros in low mode. Obtain gyromeasured disturbance time responses due to SCM, SA-3, HGAs, RWAs, SSM
thermal gradients, and COS and WFC3 mechanism articulation. The VDT shall
consist of three separate tests that need not occur consecutively. The overall
duration of the VDT is at least 12 orbits of spacecraft time including (1) at least 2
orbits at +V3 sunpoint while performing COS and WFC3 filter wheel articulation
simulating routine flight operations, (2) at least 5 orbits at +V3 sunpoint after
achieving thermal equilibrium (at least 36-hours at +V3 sunpoint), and (3) at least
5 orbits at –V1 sunpoint.
21 Mar. 2007
11
PCS Verification
L.10.4.8 (cont.)
HST
MOSES
• L.10.4.8.7 All gyros will be left in a powered on state through
the gyro to FHST alignment calibration, if it is to be performed.
Following the completion of the gyro to FHST alignment
calibration, the two gyros not in the active control loop will be
configured off. Following the gyro to FHST calibration, which
ever occurs last, one of the four gyros will be removed from the
control loop and powered off.
– L.10.4.8.8 The time allowed for OBAD maneuver will be
managed to aid in attitude maintenance until the slew missdistances and gyro biases are reduced to a sufficient level to
permit successful FGS acquisitions. The time will be increased
from 66 seconds for a 300 arc-second maneuver to 100 seconds
for a 1000 arc-second maneuver if large attitude errors are
anticipated prior to FGS acquisitions.
21 Mar. 2007
12
TCS Verification
L.10.4.13
HST
MOSES
•
L.10.4.13.1 Verify predicted temperature changes due to NOBL installation
on SSM Bays 5, 7 and 8. Bay 7 components are predicted to drop 3-4°C
with the installation of NOBLs. Bay 8 components are predicted to drop 2°C
with the installation of NOBLs.Bay 5 components are predicted to drop 810°C (TBD) with the installation of NOBLs and removal of external MLI.
•
L.10.4.13.2 Verify predicted temperature changes on STIS MAMA
components due to STIS Cooling System installation.
21 Mar. 2007
13
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
Combined OTA & FGS SM4 Requirements (L.10.4.7)
comprise 3 areas:
–L.10.4.7.1
• Cross-SI & Observatory Focus
–Coordination of telescope focus with the new & existing SIs
–L.10.4.7.2
• Positional Alignment
–SI & FGS positions and orientations
–L.10.4.7.3
• FGS commissioning/recommissioning
–Calibration of FGSs as guiders & astrometer
NOTE: Pre-existing numbering scheme for SMOV Requirements reserved
L.10.4.7 for “OTA/FGS”. New OTA-level requirements subjugate FGS section
one level down (e.g. old L.10.4.7.9 becomes L.10.4.7.3.9)
21 Mar. 2007
14
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
Basic Assumptions & Approach:
•
We will enter SMOV with HST Secondary Mirror position at best WFPC2/PC focus
(+/– 1.5 microns) and with the WFPC2/PC-to-ACS/SBC focus offset well
established.
•
We will enter SMOV with up-to-date FGS & SI V2,V3 locations.
•
this will improve initial SMOV ops and can minimize SMOV-related updates.
•
Cycle 15 CAL/OTA 11021 provides these data. Calibrations in place will be
valid for SMOV epoch.
•
We assume that SBC will be the only available ACS channel before and during
SMOV (i.e. that ACS will not undergo an SM4 repair).
•
If ACS is serviced on orbit, OTA focus determination procedures to support
requirement L.10.4.7.1.1 will need to be reevaluated.
•
We assume in our wording of these requirements that the new FGS replaces FGS3,
but plan is independent of particular FGS.
•
We do not discuss most contingencies here.
21 Mar. 2007
15
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
L.10.4.7.1 Cross-SI & Observatory Focus
–
L.10.4.7.1.1 After HST release, its focus state shall be welldetermined with sufficient ACS/SBC monitoring.
If monitoring with SBC shows OTA defocus > 5 microns, and is
consistent with STIS and NICMOS checks, then enter contingency to
assess possible corrective actions based on balancing the needs of
the SMOV schedule and science operations
COS & WFC3 image quality requirement for SMOV is ~10 microns
(Secondary Mirror equivalent).
•
•
•
•
this tolerance is for commissioning only; later science calibrations would
optimize the focus further
more stringent confocality between all SIs, if needed, can be achieved also
post-SMOV
21 Mar. 2007
16
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
L.10.4.7.2 Observatory Alignment
–
L.10.4.7.2.1 Confirm existing SIs (SBC, NIC, & STIS) postSM4 V2,V3 locations to within 2 arcsec & orientations to 0.2
deg of last pre-SM4 determination.
• less stringent than the 1 to 2 arcsec, & 0.1 to 0.17 deg
given by SBC, NIC, & STIS in their SMOV requirements
(L.10.4.3.2, L.10.4.4.2, and L.10.4.5.2).
•
–
higher quality astrometric determinations for these SIs
may be performed as part of cycle 17 science calibration,
or from data obtained during SMOV, if sufficient meet this
goal.
Perform and confirm FGS-FGS alignment. This requirement
is fully addressed in L.10.4.7.3.3, and is only mentioned here
for logical consistency.
21 Mar. 2007
17
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
L.10.4.7.3 FGS commissioning & recommissioning
L.10.4.7.3.1 Verify Guide Star Acquisition with FGS1&2. Verify that FGS1&2
remain able to acquire guide stars and track them in finelock.
•
This test will acquire and track 2 unique pairs of guide stars, varying selection of
primary and dominant FGS, and will also measure post-SM4 spacecraft jitter
characteristics.
L.10.4.7.3.2 Optimize FGS3r S-curves over its FOV. FGS3r interferometric
performance across the FGS FOV will be optimized for operations (i.e. the
guide function) via adjustment of the articulated mirror assembly (AMA).
•
The S-curves will be obtained at several locations in the FGS FOV via Transfer
mode observations of a standard star. Several iterations of the sequence, which
includes on orbit observations, analysis, and ground commanded AMA
adjustments, will be invoked to optimize the performance of the new FGS across
the FOV. This will compensate for internal alignment changes due to launch
stress and gravity release.
21 Mar. 2007
18
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
L.10.4.7.3 FGS commissioning & recommissioning (cont.)
L.10.4.7.3.3 Establish FGS-FGS alignment for all three FGSs
•
For FGS3r, derive (X,Y -> V2,V3) transformation by executing a FGS3r -> FGS
alignment (using the M35 astrometric field).
•
For FGS1&2, determine validity of pre-SM4 alignment from residuals of FGS3r
calibration. If the residuals are found to be greater than 0.1 arcsec, a SMOV
contingency consisting of full FGS-FGS alignment calibration will be activated.
Note, the Cycle 17 Calibration Plan may require much better accuracy.
L.10.4.7.3.4 Calibrate Distortion & Plate Scale of FGS3r.
•
The geometric distortions and plate scale of the newly installed FGS will be
calibrated via a mini-OFAD proposal (observations of stars in M35)
L.10.4.7.3.5 Test FGS3r Guide Star Acquisition Capability. Verify that the
new FGS can acquire and track bright and faint guide stars with acceptable
performance.
21 Mar. 2007
19
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
L.10.4.7.3 FGS commissioning & recommissioning (cont.)
L.10.4.7.3.6 Characterize FGS1r, FGS2r, FGS3 Pre-SM4. Measure Scurves, geometric distortion, and plate scale for all FGS for a pre-SM4
baseline characterization.
L.10.4.7.3.7 Re-commission FGS1 & FGS2 (Operations & Science).
Verify the stability of the S-Curves and the validity of the distortion and
plate scale calibration of FGS1 & 2 post-SM4 by comparison to pre-SM4
observations.
•
This requirement will re-commission FGS1r for science.
L.10.4.7.3.8 Check Near Term Stability of FGS3r.
•
Monitor S-curves to verify the values assigned to guide star acquisition and
tracking parameters remain valid.
•
Verify that SMOV distortion & plate scale calibrations remain valid.
21 Mar. 2007
20
OTA/FGS Verification
L.10.4.7 (cont.)
HST
MOSES
L.10.4.7.3 FGS commissioning/recommissioning
–
L.10.4.7.3.9 Calibrate FGS3r PMT. Data from the Mini-OFAD
(L.10.4.7.3.4) will be analyzed to obtain the counts versus
magnitude calibration for FGS3r.
–
L.10.4.7.3.10 Map FGS3r Obscuration Zone (OCS). NOTE: will
be performed on the ground.
–
L.10.4.7.3.11 Calibrate FGS3r PMT Dark Count. Determine the
average dark rate for each PMT (internal, performed during
SM4).
21 Mar. 2007
21
WFC3 Verification
L.10.4.1
HST
MOSES
Basic assumptions:
–
–
–
–
Re-use as much as possible the ACS SM3B requirements
Maintain three sections: engineering, optical alignment, calibration
Avoid implementation details
Add pointer to relevant CEIS spec requirements. This allows us to
keep the SMOV requirements as a document standing on its own
while maintaining the requirement traceability that independent
reviews have asked the WFC3 project.
– Unless otherwise stated the requirements can be implemented with
SMS commanding.
21 Mar. 2007
22
WFC3 Verification
L.10.4.1
HST
MOSES
• WFC3 SMOV requirements are basically
unchanged since Fall 2003 Review
– IR Operate Setpoint changed from 150K to 145K
– May delete requirement to vary CCD and IR setpoints
• Will want to revisit requirements once more after
completion of SLTV#2 (August 2007)
21 Mar. 2007
23
WFC3 Verification
L.10.4.1
HST
MOSES
L.10.4.1.1 Engineering Requirements
•
L.10.4.1.1.1 WFC3 entry into each of four instrument states
(Boot, Hold, Operate, Observe) shall be demonstrated.
Operations shall be commanded via stored commands
transmitted over the Supervisory Bus.
Relevant CEIS requirements: 4.10.1.1 Observe modes
•
L.10.4.1.1.2 WFC3 entry into each of the defined detector
states shall be demonstrated. Operations shall be commanded
via stored commands transmitted over the Supervisory Bus.
21 Mar. 2007
24
WFC3 Verification
L.10.4.1
HST
•
L.10.4.1.1.3 WFC3 command and engineering data interface via the
RIU and science data transmission via the Science Data Formatter
(SDF) shall be verified by monitoring of normal configuration and
science activities.
•
L.10.4.1.1.4 Onboard memory shall be checked by performing a full
dump of the CS (control section) EEPROM, PROM, and EXEC RAM,
and verify a match with the ground image.
MOSES
» Special Commanding
•
L.10.4.1.1.5 The ability to read and write data from and to the science
data buffer shall be demonstrated.
•
L.10.4.1.1.6 The performance of the Channel Select Mechanism, M1
and IM2 Alignment and Focus Corrector Mechanisms, UVIS Selectable
Optical Filter Assembly, IR Filter Wheel, and UVIS CCD shutter shall
be verified.
Relevant CEIS requirements: 4.10.1.4 Alignment modes
21 Mar. 2007
25
WFC3 Verification
L.10.4.1
•
HST
MOSES
L.10.4.1.1.7 The functionality of the WFC3 Tungsten and Deuterium
calibration lamps shall be verified. Operation of the deuterium lamp
shall be deferred for an initial outgassing period following release of the
observatory, as defined in the CARD 3.4.13.11.
Relevant CEIS requirements: 4.10.1.2 Internal Calibration Lamps
•
L.10.4.1.1.8 Functionality of the WFC3 UVIS CCD detector shall be
demonstrated. This shall include the proper accumulation of signal
over a specified time interval and data readout, readout of subarrays,
and on-chip binning.
Relevant CEIS requirements: 4.10.2 CCD detector operations requirements
•
L.10.4.1.1.9 Functionality of the WFC3 IR detector shall be
demonstrated. This shall include the proper accumulation of signal
over a specified time interval and multiaccum data readout, readout of
subarrays, and characterization of the reference pixels.
Relevant CEIS requirements: 4.10.3 IR detector operations requirements
21 Mar. 2007
26
WFC3 Verification
L.10.4.1
•
HST
MOSES
L.10.4.1.1.10 The ability of the TECs to cool and stably control the
detectors shall be tested at a small number of temperature set points, in
order to determine a cold stable operating point. The goal is to
demonstrate that this point be at least as cold as –83C for the UVIS CCDs
and 145K for the IR detector. WFC3 detectors cannot be cooled before 21
days in vacuum (CARD 3.4.13.15).
Relevant CEIS requirements: 4.7 CCD thermal control, 4.9 IR thermal control
» Special Commanding?
•
L.10.4.1.1.11 The ability to perform a CCD anneal shall be demonstrated.
Relevant CEIS requirements: 4.7.2 CCD detector warm operations
•
L.10.4.1.1.12 WFC3 operations shall be managed to minimize risk of
contamination of its optical surfaces by materials outgassed either internally
or from other units installed during the SM as well as from the payload bay
environment during servicing (CARD 3.4.13.15, 3.4.13.16, 3.4.13.17) . A
contamination monitoring program shall be initiated as early as possible
after the SM.
Relevant CEIS requirements: 6.4 Contamination control
21 Mar. 2007
27
WFC3 Verification
L.10.4.1
HST
MOSES
L.10.4.1.2 Optical Alignment Requirements
•
L.10.4.1.2.1 The encircled energy and image diameter shall be
measured over a grid of focus and tilt positions for both M1 and IM2
correctors. These measurements shall be used to set the nominal
corrector positions.
Relevant CEIS requirements: 4.10.1.4 Alignment modes
•
L.10.4.1.2.2 The image quality at the detectors over the full field shall
be measured via broad and narrow band imaging of stars. The
requirement for encircled energy in the UVIS channel field center is
75% within a diameter of 0.25 arcseconds, through the F631N filter.
The requirement for encircled energy in the IR channel field center is
75% within a diameter of 0.60 arcseconds, for a star observed through
the F164N.
Relevant CEIS requirements: 4.3.2 Image quality
21 Mar. 2007
28
WFC3 Verification
L.10.4.1
•
HST
MOSES
L.10.4.1.2.3 The pointing stability of the OTA-WFC3
combination shall be measured over at least three orbits
including hot and cold spacecraft attitudes. The purpose of
these measurements is to confirm that the typical thermal
environment after SM4 does not cause unacceptable image
drifts.
Relevant CEIS requirements: 4.3.2.4 Image jitter, 4.3.2.5 Image drift
•
L.10.4.1.2.4 The WFC3 Point Spread Function (PSF) shall be
measured over a large dynamic range in order to study PSF
wings and image ghosts.
Relevant CEIS requirements: 4.3.2.1 UVIS point source profile, 4.3.2.2 IR
point source profile, 4.3.2.6 Ghost images, 4.3.2.7 Large angle stray
light
21 Mar. 2007
29
WFC3 Verification
L.10.4.1
HST
MOSES
L.10.4.1.3 Calibration Requirements
•
L.10.4.1.3.1 The plate scale, orientation and geometric distortion shall
be measured for each of the WFC3 channels by imaging an astrometric
field.
Relevant CEIS requirements:4.3.1.1 Pixel spacing, 4.3.1.2 Field of view, 4.3.1.3
Field of view distortion, 4.3.1.5 Geometric distortion
•
L.10.4.1.3.2 The absolute FGS/WFC3 alignment shall be determined .
•
L.10.4.1.3.3 Dark rate, read noise and CTE shall be measured for the
CCD detector. The hot pixel creation rate shall be assessed and the
efficacy of the hot annealing cycle shall be demonstrated. The stability
of these parameters over a 30 day baseline shall be determined.
Relevant CEIS requirements: 4.6.3 CCD readout noise, 4.6.4 CCD Dark current,
4.6.9 CTE and radiation damage, 4.7.2 CCD detector warm operation
21 Mar. 2007
30
WFC3 Verification
L.10.4.1
•
HST
MOSES
L.10.4.1.3.4 Dark rate, background level, and read noise shall
be measured for the IR detector. IR bad pixels shall be
characterized. The stability of these parameters over a 30-day
baseline shall be determined.
Relevant CEIS requirements: 4.4.8 IR Background, 4.8.3 IR readout noise,
4.8.4 IR dark current, 4.8.5 IR amplifier glow
•
L.10.4.1.3.5 The behavior of both channels during SAA
passages shall be characterized. The SAA afterimage shall be
measured for the IR detector.
Relevant CEIS requirements: 4.6.15 CCD detector cosmic ray
susceptibility, HgCdTe detector cosmic ray susceptibility
Æ Special handling
21 Mar. 2007
31
WFC3 Verification
L.10.4.1
•
HST
MOSES
L.10.4.1.3.6 Instrument sensitivity vs. wavelength shall be measured
for a subset of WFC3 spectral elements. Sensitivity measurements
shall be performed using astronomical standard stars. The photometric
stability shall be determined over several orbits. As part of this
process, UV sensitivity measurements shall be obtained as early as
possible, to enable early trending of UV sensitivity.
Relevant CEIS requirements: 4.4.1 wavelength range, 4.4.2 optics throughput, 4.4.3
spectral range stability, 4.6.2 CCD QE, 4.8.2 IR detector QE
•
L.10.4.1.3.7 The flat field uniformity per pixel and cosmetic defect
fraction shall be measured for both WFC3 detectors. The ability to
determine the residual response variation using the WFC3 internal
calibration sources shall be demonstrated. The difference between sky
flats and internal flats and temporal stability of the flat field correction
shall be assessed.
Relevant CEIS requirements: 4.6.11 CCD flat field, 4.8.11 IR flat field
21 Mar. 2007
32
COS Verification
L.10.4.2
HST
MOSES
L.10.4.2.1 Engineering Activities
•
L.10.4.2.1.1 Instrument States
COS entry into each of four instrument states (Boot, Hold, Operate, Observe)
shall be demonstrated. Operations shall be commanded via RIU (Remote
Interface Unit) commands transmitted over the Supervisory Bus.
•
L.10.4.2.1.2 Detector States
COS entry into each of the defined detector states shall be demonstrated.
Operations shall be commanded via RIU commands transmitted over the
Supervisory Bus.
NUV detector states:
HOLD, Low Voltage ON (LVON), High Voltage ON (HVON),
and High Voltage in SAA (HVSAA)
FUV detector states:
HOLD, BOOT, OPERATE, HV LOW, HV NOMINAL,
HV SEGMENT A, and HV SEGMENT B
21 Mar. 2007
33
COS Verification
L.10.4.2
HST
MOSES
•
L.10.4.2.1.3 Data Interface and Data Transmission Verification
COS command and engineering data interface via the RIU, and science data
transmission via the Science Data Formatter (SDF), shall be verified by
monitoring of normal configuration and science activities.
•
L.10.4.2.1.4 On-board Memory Check
The ability to load and dump on-board memory shall be demonstrated.
Special Commanding
•
L.10.4.2.1.5 Science Data Buffer Check
The ability to read and write data from and to the science data buffer shall be
demonstrated. The science data buffer shall also be checked for bit flips
during SAA passage.
Special Commanding
21 Mar. 2007
34
COS Verification
L.10.4.2
HST
MOSES
•
L.10.4.2.1.6 Test of NUV Detector Initial Turn-on and Recovery after Anomalous Shutdown
The procedure used for initial turn-on and recovery after anomalous shutdown of NUV MAMA
detector shall be tested.
Special Commanding
•
L.10.4.2.1.7 Test of FUV Detector Initial Turn-on and Recovery after Anomalous Shutdown
The procedure used for initial turn-on and recovery after anomalous shutdown of FUV XDL
detector shall be tested.
Real Time Commanding
•
L.10.4.2.1.8 Functionality and Operations of Detectors
Functionality and operations of the two COS detectors shall be demonstrated. This shall include:
– the proper accumulation of signal over a specified time interval in ACCUM & TTAG readout
mode;
– readout of subarrays;
– standard auto-wavelength calibration for ACCUM mode with the PSA and for TTAG and
ACCUM mode with the Bright Object Aperture (BOA); FLASH=no
– TAG-FLASH operational mode (standard wavelength calibration for TTAG mode with the
PSA); FLASH=yes
– on-board Doppler correction in ACCUM mode.
21 Mar. 2007
35
COS Verification
L.10.4.2
HST
MOSES
•
L.10.4.2.1.9 QE Enhancement Grid Tests
The functionality of the FUV detector shall be tested with and without
the QE enhancement grid turned on.
•
L.10.4.2.1.10 Performance of Mechanisms
The performance of the external shutter, Aperture Mechanism (ApM),
Optics Select Mechanisms OSM1 and OMS2, and FUV detector door
shall be verified either by execution of engineering tests or as part of
normal SMOV operations.
•
L.10.4.2.1.11 Functionality of Lamps
The functionality of the COS Pt-Ne and D2 calibration lamps shall be
verified either by execution of engineering tests or as part of normal
SMOV operations.
21 Mar. 2007
36
COS Verification
L.10.4.2
HST
MOSES
L.10.4.2.2 Contamination
•
L.10.4.2.2.1 Contamination Management
COS operations shall be managed to minimize the risk of
contamination of its optical surfaces by outgassing material. The
COS external shutter shall be used to provide protection against
illumination by the bright earth. A contamination monitor program
shall be initiated as soon as possible after the servicing mission
(COS CARD item 3.4.12.20).
21 Mar. 2007
37
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.2.2 Upon release the COS instrument shall
undergo a period of depressurization and
decontamination.
– The FUV detector door shall not be opened until the COS internal
pressure is less than 100 micro-Torr for 12 consecutive hours.
– The NUV MAMA detector HV shall not be turned on until the internal
pressure is less than 20 micro-Torr for 12 consecutive hours.
– The FUV XDL detector HV shall not be turned on until the internal
pressure is less than 10 micro-Torr for 12 consecutive hours.
– The D2 and Pt-Ne lamps shall not be operated until the internal pressure
is less than 10 micro-Torr for 12 consecutive hours.
(COS CARD items 2.4.12.3, 2.4.12.4, 2.4.12.7, 2.4.12.8, 3.14.12.14)
21 Mar. 2007
38
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.2.3 Opening of FUV Detector Door
The HV of the FUV XDL detector and the NUV MAMA detector shall
be off when the FUV detector door opens in case of release of gases
during the opening of the door.
21 Mar. 2007
39
COS Verification
L.10.4.2
HST
MOSES
L.10.4.2.3 Science Verification & Calibration
•
L.10.4.2.3.1 Internal NUV calibrations shall be conducted and
measurements of the post-launch alignment of the optics shall
be obtained. These include:
– a detector dark image;
– an internal wavelength calibration spectrum using each NUV
grating at each central wavelength setting;
– a TA1 image of the wavelength calibration lamp;
– intensity of each lamp in a single mode. Special Commanding
21 Mar. 2007
40
COS Verification
L.10.4.2
HST
MOSES
L.10.4.2.3.2 The relationship between the HST coordinate system
and the COS primary science aperture (PSA) shall be measured. The
NUV channel in the TA1 mode shall be used to locate the PSA in the HST
V2, V3 coordinates. This is accomplished by raster scanning in a 4x4 grid,
monitoring the count rate in the NUV detector, and calculating the location
of the HST OTA Point Spread Function (PSF) with respect to the PSA.
The calculating is done on the ground after the observations are complete.
21 Mar. 2007
41
COS Verification
L.10.4.2
HST
MOSES
•
L.10.4.2.3.3 The locations of the spectra for each NUV mode
shall be measured. This is done by observing an astronomical target
and acquiring a spectrum using G185M, G225M, G285M, and G230L
gratings, as well as a TA1 image.
•
L.10.4.2.3.4 The NUV channel shall be focused. This is done by
conducting a focus scan of each of the NUV gratings at one central
wavelength setting and of the TA1 mirror while observing an
astronomical target.
21 Mar. 2007
42
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.3.5 The target acquisition algorithms for NUV
operations shall be tested and verified.
– L.10.4.2.3.5.1 NUV undispersed light target acquisition in
ACQ and ACQ/IMAGE mode shall be tested.
– L.10.4.2.3.5.2 NUV dispersed light target acquisition in
ACQ, ACQ/PEAKD and ACQ/PEAKXD mode shall be tested.
21 Mar. 2007
43
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.3.6 The imaging performance of the NUV channel shall be
calibrated.
– L.10.4.2.3.6.1 The PSF in NUV imaging (TA1) mode shall be
measured.
– L.10.4.2.3.6.2 The plate scale of the NUV detector in imaging
(TA1) mode shall be measured.
– L.10.4.2.3.6.3 The throughput of the NUV imaging (TA1) mode
shall be tested both in mirror A and mirror B configurations.
21 Mar. 2007
44
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.3.7 The spectroscopic performance of the NUV channel
shall be calibrated.
– L.10.4.2.3.7.1 The zero point offsets in the dispersion relations for
the NUV spectroscopic modes for each central wavelength setting
shall be measured.
– L.10.4.2.3.7.2 The spectral resolution of the NUV spectroscopic
modes shall be measured.
– L.10.4.2.3.7.3 The spatial resolution of the NUV spectroscopic
modes shall be measured.
21 Mar. 2007
45
COS Verification
L.10.4.2
HST
MOSES
– L.10.4.2.3.7.4 The flat-field response of the NUV detector shall be
measured.
– L.10.4.2.3.7.5 The sensitivity of each NUV grating for each
central wavelength setting shall be measured.
– L.10.4.2.3.7.6 The stability of a single mode of the NUV channel
over several orbits shall be characterized to determine if there are
signatures of structural or thermal distortions in the data.
– L.10.4.2.3.7.7 The acquisition of spectra having S/N>30 using
normal data acquisition and reduction techniques shall be
demonstrated for each NUV mode. Data shall be obtained which
are capable of demonstrating spectra with S/N>100 for a single NUV
medium resolution mode.
21 Mar. 2007
46
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.3.8 Internal FUV calibrations shall be conducted and
measurements of the post-launch alignment of the optics shall
be obtained. These include:
– a detector dark image;
– an internal wavelength calibration spectrum using each FUV
grating at each central wavelength setting;
– intensity of each lamp in a single mode. Special Commanding
21 Mar. 2007
47
COS Verification
L.10.4.2
HST
MOSES
•
L.10.4.2.3.9 The locations of the spectra for each FUV mode
shall be measured. This is done by observing an astronomical
target and acquiring a spectrum using G130M, G160M, and G140L
gratings.
•
L.10.4.2.3.10 The FUV channel shall be focused. This is done by
conducting a focus scan of each of the FUV gratings at one central
wavelength setting while observing an astronomical target.
•
L.10.4.2.3.11 The target acquisition algorithms for FUV
operations shall be tested and verified.
– L.10.4.2.3.11.1 FUV dispersed light target acquisition in
ACQ, ACQ/PEAKD and ACQ/PEAKXD mode shall be tested.
21 Mar. 2007
48
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.3.12 The spectroscopic performance of the FUV channel
shall be calibrated.
– L.10.4.2.3.12.1 The zero point offsets in the dispersion relations for
the FUV spectroscopic modes for each central wavelength setting
shall be measured.
– L.10.4.2.3.12.2 The spectral resolution of the FUV spectroscopic
modes shall be measured.
– L.10.4.2.3.12.3 The spatial resolution of the FUV spectroscopic
modes shall be measured.
21 Mar. 2007
49
COS Verification
L.10.4.2
HST
MOSES
– L.10.4.2.3.12.4 The flat-field response of the FUV detector shall be
measured.
– L.10.4.2.3.12.5 The sensitivity of each FUV grating for each central
wavelength setting shall be measured.
– L.10.4.2.3.12.6 The stability of a single mode of the FUV channel over
several orbits shall be characterized to determine if there are signatures
of structural or thermal distortions in the data.
– L.10.4.2.3.12.7 The acquisition of spectra having S/N>30 using normal
data acquisition and reduction techniques shall be demonstrated for
each FUV mode. Data shall be obtained which are capable of
demonstrating spectra with S/N>100 for a single FUV medium
resolution mode.
21 Mar. 2007
50
COS Verification
L.10.4.2
•
HST
MOSES
L.10.4.2.3.13 The position and throughput of the BOA, and spectral
resolution of the data acquired through this aperture shall be
measured. This is done by observing an astronomical target in imaging
mode and acquiring a spectrum in each NUV and FUV grating at a single
central wavelength setting.
21 Mar. 2007
51
ACS VERIFICATION
L.10.4.3
HST
MOSES
• Basic Assumptions
– Work is currently in progress to evaluate various repair solutions
for ACS.
– Here we assume a fully repaired ACS, where all the 3 ACS
channels (WFC, HRC and SBC) are functioning.
– However, in some of the repair scenarios, all the 3 channels
may not be available, which would need some revision of these
requirements (mostly, removal of the requirements for the
unavailable channels.)
– Some additional tests may be required depending on the
adopted repair solution for ACS.
21 Mar. 2007
52
ACS VERIFICATION
L.10.4.3
HST
MOSES
• Basic Approach
– Include the minimum set required for starting GO science. Where
possible, do the tests as part of the regular calibration plan.
– Maintain four sections: engineering, target-acquisition, optical
alignment, calibration.
– Use ACS/SBC for focus check, and BEA targets with SBC to
monitor UV contamination.
21 Mar. 2007
53
HST
ACS VERIFICATION
L.10.4.3
MOSES
L.10.4.3.1 Engineering Requirements
L.10.4.3.1.1 Hot-pixel annealing: A hot pixel annealing procedure shall be
executed just before CCD activation, and every four weeks thereafter, thus
resuming the standard cadence in force before SM4.
L.10.4.3.1.2 CCD Temperature: The ability of the TEC to cool and stably
control the CCD at their nominal operating temperatures shall be tested and
verified through the engineering telemetry data during the course of normal
operations. Failure to reach the expected temperature will trigger an existing
contingency program (CCD temperature set point determination) that was
used successfully in SM3B.
54
HST
ACS VERIFICATION
L.10.4.3
MOSES
L.10.4.3.1 Engineering Requirements (Contd.)
L.10.4.3.1.3 Detector characteristics: After reaching the appropriate
operating temperature, a mini-functional test shall be executed for all ACS
detectors to characterize their performances in the new thermal and electrical
environment. However, the high voltage for the SBC detector shall not be
activated until at least four days after release and not until the pressure in the
aft shroud has been below 5e-6 Torr for at least 24 hours.
The mini-functional test shall consist of an enriched version of the nominal
daily/monthly monitoring program, and is to include bias, dark and flat field
frames. The observations will be used to evaluate the noise characteristics
of the detectors, which will be compared with pre-SM4 observations.
L.10.4.3.1.4 UV Monitoring program: Following the successful activation of
the CCD, the standard UV monitoring program shall resume as soon as
possible, limited initially to the HRC. The SBC monitoring program will need a
choice of appropriate BEA targets for which pre-SM4 observations are
available.
55
HST
ACS VERIFICATION
L.10.4.3
MOSES
L.10.4.3.2 Target Acquisition Requirements
L.10.4.3.2.1 Aperture locations: The location of a reference aperture shall be
determined for all three ACS channels with respect to the FGS reference frame
to within an accuracy of 1 arc second in V2-V3 coordinates and 10 arc minute
in aperture rotation angle by observing a well-observed dense stellar field. The
same observations will be used to investigate any possible changes in
geometric distortions.
L.10.4.3.2.2 Coronographic spot location: The location of the coronographic
spots shall be measured with one set of observations.
56
HST
ACS VERIFICATION
L.10.4.3
MOSES
L.10.4.3.3 Optical Alignment Requirements
L.10.4.3.3.1 Image Quality: The camera mode image quality at the detectors over
the full field shall be measured via broad and narrow-band imaging of a sparse
stellar field. It will be verified that the encircled energy within a 0.25 arc second
diameter (in broad-band filters for which pre-SM4 observations exist) is within
3 σ (5%) of pre-SM4 value. The observations in F550N filter will be used to
complement the focus measurements.
L.10.4.3.3.2 A decrease of the encircled energy by more than 3 σ will trigger
an existing contingency program, successfully used in SM3B (ACS fine
corrector alignment), whereby the encircled energy and image diameter are
measured over a grid of focus and tilt positions for both IM1 and M1
correctors. These measurements shall be used to set the nominal corrector
positions.
L.10.4.3.3.3 Coronographic PSF: The ACS Point Spread Function (PSF) in
coronographic mode shall be measured.
57
HST
ACS VERIFICATION
L.10.4.3
MOSES
L.10.4.3.4 Calibration Requirements
L.10.4.3.4.2 Detector sensitivities and instrument configurations:
Observations of reference stellar fields (e.g. 47 Tuc and NGC188 for the
CCD, NGC6681 for the SBC) shall be obtained for a subset of the ACS
imaging modes and filters. Through comparison with the existing pre-SM4
data, these observations shall be used to measure, for each ACS channel:
1. the detectors plate scale, orientation and geometric distortion;
2. the relative location of each aperture with respect to the FGS reference
frame;
3. the instrumental relative and absolute sensitivity as a function of
wavelength;
4. the uniformity of the flat field at low frequency.
Discrepancies in key filter/modes exceeding those observed in the course of
the preceding calibration cycles shall be promptly investigated and
characterized through contingency calibration observations.
58
HST
ACS VERIFICATION
L.10.4.3
MOSES
L.10.4.3.4 Calibration Requirements (Contd.)
L.10.4.3.4.3 Pixel-to-pixel sensitivities: Variations in the ACS detectors'
sensitivity on a pixel-to-pixel scale and cosmetic defects shall be measured
for all three channels through observations with the internal calibration lamps.
59
STIS Verification
L.10.4.5
•
HST
MOSES
Basic Assumptions and Approach
– STIS is an existing instrument, but due to a new circuit board and long inactivity, it
will require extra checks.
– Assume that the STIS AT/FT was completed during the servicing mission.
– Re-use, where possible, previously defined SM4 requirements, supplemented with
an updated subset of the original SM2 requirements.
– Avoid including implementation details in requirements.
– Check for problems which could impact the ability to obtain good quality
science data.
– Defer until after SMOV most calibrations that can be applied retroactively.
– Unless otherwise stated, the requirements can be implemented with SMS
commanding.
– Most special commanding will re-use previous work.
(Comments are in blue italics, and are not part of formal requirements)
21 Mar. 2007
60
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5 STIS Verification Requirements
L.10.4.5.1 Engineering Requirements
L.10.4.5.1.1 STIS entry into each of four instrument states (Boot, Hold,
Operate, Observe) shall be demonstrated.
L.10.4.5.1.2 STIS entry into each of the defined detector states
needed to support normal operations shall be demonstrated.
L.10.4.5.1.3 STIS command and engineering data interface via the
RIU and science data transmission via the Science Data Formatter
(SDF) shall be verified by monitoring of normal configuration and
science activities.
21 Mar. 2007
61
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.1.4 Onboard memory will be checked by performing dumps
of EEPROM, PROM, EDAC RAM and Buffer RAM. (Special
Commanding)
L.10.4.5.1.5 Conduct a test of the ability to write to and read from the
CS (control section) Buffer RAM. (Special Commanding)
L.10.4.5.1.6 Verify the proper functioning of all STIS mechanisms
needed for routine operations (the three MSM wheels, the aperture
wheel, CIM, echelle blockers, CCD shutter, aperture door, & mode
isolation shutter) over the full ranges of motion needed for normal
operations. Contingency: verification of the corrector alignment
mechanisms will be done only as part of any alignment or focus
adjustments. Movement of the corrector mechanisms should
otherwise be avoided.
21 Mar. 2007
62
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.1.7: Check the functioning of the calibrations lamps used for
routine science and SMOV operations (LINE, Tungsten, HITM1, &
HITM2), at each of the current levels used for normal operations.
Contingency: if one or more of these lamps either shows
significantly degraded behavior or fails to function, then make those
changes which are necessary to support science operations; this
contingency may include changes to the ground system and/or onboard tables to allow substitution of one of the operable lamps for
the critical functions of a failed one. Verification of the Krypton and
Deuterium lamps may be deferred until after SMOV.
21 Mar. 2007
63
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.1.8 The CCD shall be annealed as necessary to ameliorate
accumulated hot pixels.
L.10.4.5.1.9 During the course of routine operations throughout
SMOV, the temperature variations of each detector will be monitored
and compared to previous side-2 values. The ability of the CCD
TEC to cool that detector to the required operating temperature
range will be evaluated.
21 Mar. 2007
64
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.1.10 Perform a mini-functional test of the STIS CCD.
L.10.4.5.1.11 Verify the proper functioning of the MAMA detectors by
following procedures similar to those defined for MAMA anomalous
recovery (STIS ISR 98-03). A MAMA detector should not be
otherwise used prior to completing this functional test. The high
voltage for the STIS MAMA detectors will not be activated until at
least four days after release and not until the pressure in the aft
shroud has been below 5x10−6 torr for at least 24 hours.
(Special Commanding. Four day wait to be confirmed based on contamination models).
L.10.4.5.1.12 The STIS Deuterium and Krypton lamps will not be
operated until 3 weeks after release.
21 Mar. 2007
65
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.2 Target Acquisition Requirements
L.10.4.5.2.1 The location of a reference STIS camera aperture shall
be determined with respect to the FGS reference frames to an
accuracy of 1 arc second in V2-V3 coordinates and 10 arc minutes
in aperture rotation angle.
L.10.4.5.2.2 The ability to acquire and properly center targets with
standard ACQs and the ability to center targets in small apertures
with ACQ/PEAK exposures will be demonstrated for both standard
and E1 aperture positions.
(E1 aperture positions are defined near CCD readout; ~ 20” away from standard
acquisition aperture. This requires a much larger pointing change after a standard
ACQ than do other apertures).
21 Mar. 2007
66
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.3 Optical Alignment Requirements
L.10.4.5.3.1 An aperture throughput test using a previously observed
external point source calibration target shall be used to assess STIS
focus. The slit plane encircled energy vs. wavelength shall also be
measured using this external target.
Contingency: if throughput is down by more than 3 sigma (7%),
relative to the expected mean after correction for expected secular
sensitivity changes, additional tests and perhaps a STIS corrector
alignment and/or focus adjustment shall be done. This test is
dependent on the setting of the HST secondary mirror position,
which must have been first set to its expected nominal focus.
(Contingencies to adjust alignment require special commanding. For STIS, best
focus is set at the plane of the aperture wheel, not at the detectors.).
21 Mar. 2007
67
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.3.2 The positioning of the STIS aperture wheel should be
checked for a representative subset of STIS apertures, and
compared to previous side-2 measurements.
Contingency: if operationally significant discrepancies are found in
relative aperture positions, all aperture locations will be remeasured,
and appropriate updates made to ground and on-board calibration
tables.
L.10.4.5.3.3 For each optical element in the MSM, (except for MAMA
imaging modes), the location of a lamp spectrum or slit image on the
detector appropriate for that optical element shall be compared to
previous side-2 values.
Contingency: operationally significant shifts shall be corrected by
updating on-board mechanism calibration tables. Only one MSM
position of each optical element need be tested. Checks of MAMA
imaging mode alignments may be deferred until after SMOV.
21 Mar. 2007
68
STIS Verification
L.10.4.5
HST
MOSES
L10.4.5.3.4. The spectroscopic image quality and cross dispersion PSF at each
detector will be measured as a function of position and wavelength using an
external point source calibration target. This test is dependent on the
settings of the HST secondary mirror position and of the STIS corrector
mechanism, which must have been first set to their nominal values.
L.10.4.5.3.5 The pointing stability of external targets on the STIS CCD
detector, and the relative stability of the CCD detector with respect to the
aperture plane, will be monitored over the course of the two orbits
immediately following an attitude change that is expected to produce a
significant thermal change in STIS. Separate test(s) will be done to
measure the stability of at least one of the two MAMA detectors with respect
to either the aperture plane or an external target, over two orbits following a
similar large maneuver.
21 Mar. 2007
69
STIS Verification
L.10.4.5
HST
MOSES
L.10.4.5.4 Calibration Requirements
L.10.4.5.4.1 The dark rate for each detector shall be measured for
normal operating temperatures and conditions. For the CCD, bias
and read-noise measurements will also be made. Sufficient CCD
dark and bias measurements will be done to allow proper calibration
of other STIS SMOV and ERO data. Sufficient NUV MAMA dark
measurements will be taken to determine whether the
phosphorescent window glow has declined to a level that will
support expected GO observations. The FUV MAMA dark rate will
be monitored over at least one 5 orbit interval to measure how the
dark rate increases as a function of time after detector high voltage
turn-on.
21 Mar. 2007
70
STIS Verification
L.10.4.5
HST
MOSES
L10.4.5.4.2. A test will be done to check predictions for CTI
losses on the STIS CCD detector. Results will be
evaluated for any impact on planned GO observations.
L 10.4.5.4.3 For one wavelength setting of each STIS
grating, the throughput will be checked using an external
calibration target.
21 Mar. 2007
71
NICMOS/NCS Verification
L.10.4.4
HST
MOSES
Basic Assumptions and Approach
1.
Re-use as much as possible the NICMOS SMOV3b
requirements/proposals
2.
Perform NICMOS SMOV4 to verify operation and basic performance
3.
Move some SMOV3b verification requirements to regular (extended)
calibration programs to follow immediately after SMOV4
NICMOS SMOV4 activities partially based on recommendations from
the NICMOS group following the NCS/NICMOS safing in August
2003 (scenario 3). Potential problems associated with the thermal
cycling include mechanical and optical misalignments and increased
particulate matter (‘Grot’).
21 Mar. 2007
72
NICMOS/NCS Verification
L.10.4.4
HST
MOSES
Basic Assumptions and Approach (cont’d)
• Minimize NCS off–time in order minimize dewar warm–up
• NICMOS SMOV activities have to wait until the dewar, VCS and filter
wheels reach nominal operating temperatures (detector temp ~ 77.1 K)
-
Estimated dewar temperature with NCS off and NICMOS in safe mode
T = 176[1 - exp(-t/183)] + 80 K (t in hours)
-
Warm–up rate varies from event to event (Aug 2003/ Jan 2007)
NCS off for ~9 days –> detector warm–up ~120K (final temp: ~200K)
Cool–down rate uncertain, but 7–12 days reasonable, based on 2003
and 2007 NICMOS safing event (nb. uncertain).
21 Mar. 2007
73
NICMOS/NCS Verification
L.10.4.4
HST
MOSES
August 2003
January 2007
21 Mar. 2007
74
NICMOS/NCS Verification
L.10.4.4
HST
MOSES
SMOV4 + post-calibration issues
• Define minimum verification activity
–
–
–
–
Engineering and target acquisition
Optical characterization
Calibration (NICMOS–specific capabilities: coronagraphy)
Thermal characterization
• post-SMOV Calibration
– Most calibration verification/tests
– Science operation may start before calibration complete
21 Mar. 2007
75
NICMOS/NCS Verification
L.10.4.4
HST
MOSES
L.10.4.4 NICMOS Verification Requirements
L.10.4.4.1 Engineering Activation Requirements
L.10.4.4.1.1 The ability to command NICMOS via the RIU, science data transmission via
the SDF, and the ability of NICMOS to transition between primary operational states
(HOLD, BOOT, SAA-OPER, OPERATE and OBSERVE) shall be verified. This test
can be done before reaching nominal operating temperature.
L.10.4.4.1.2 Operation of the NICMOS mechanisms (PAM, FOM, and filter wheels) shall
be tested. PAM motion over the range needed to assure focus in all three NICMOS
cameras (best achievable focus for NIC3). The ability to reposition the field offset
mirror (FOM) over the range needed to remove vignetting in NIC3 shall be
demonstrated. Filter wheel motion shall be verified for each camera.
L.10.4.4.1.3 Verify the basic operating characteristics of the flight detectors through a
series of multiple non-destructive readouts as a function of bias voltage.
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NICMOS/NCS Verification
L.10.4.4
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MOSES
L.10.4.4.2 Target Acquisition Requirements
L.10.4.4.2.1 The location of each NICMOS camera aperture shall be
determined with respect to the FGS reference frames to an accuracy
of +/-2 arcseconds in V2-V3 coordinates and 7 arcminutes in
aperture rotation angle for Camera 2 and 1 degree for cameras 1
and 3.
L.10.4.4.2.2 The Mode-2 coronagraphic target acquisition shall be
characterized and measured with a precision of ~1/10 of a pixel.
Acquisition of the target and the coronagraphic hole shall be shown
to be repeatable, within the precision given, using the onboard flight
software.
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NICMOS/NCS Verification
L.10.4.4
HST
MOSES
L.10.4.4.3 Optical Requirements
L.10.4.4.3.1 The optical plate scales at each of the detector focal
planes shall be measured, with a precision of better than 0.1% in
each camera.
L.10.4.4.3.2 PAM focus setting should be measured to establish the
best focus focus for each camera. The encircled energy within 100
mas (200 mas for camera 3) radius of an unresolved point source
shall be measured. In case the total wavefront error exceeds λ/14
for NIC1 and NIC2 at 1.1 and 1.6 microns, respectively, a fine
optical alignment program will be implemented.
L.10.4.4.3.3 The best coronagraphic focus shall be determined. The
purpose of this test is to establish the PAM position to optimize the
contrast in the coronagraphic image.
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NICMOS/NCS Verification
L.10.4.4
HST
MOSES
L.10.4.4.4 Calibration Requirements
L.10.4.4.4.1 The performance of the NICMOS coronagraph shall be
characterized. The goal is to provide the best achievable
target/background contrast ratio.
L.10.4.4.4.2 NICMOS geometric stability will be characterized by
measuring the lateral motion of the image in the Camera 2 focal
plane.
L.10.4.4.4.3 Detector noise, read-noise and dark current shall be
measured throughout the SMOV period through a series of dark
exposures.
L.10.4.4.4.4 HST+NICMOS thermal emission will be characterized in
a subset of spectral elements over the duration of SMOV.
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NICMOS/NCS Verification
L.10.4.4
HST
MOSES
L.10.4.4.5 NICMOS Cooling System (NCS) Engineering Verification Requirements
L.10.4.4.5.1 Configure the NCS to re-cool NICMOS detectors. The goal during SMOV is
to verify the capability to maintain the weighted average of the neon inlet and outlet
temperatures at a desired setpoint in the range 72-73 K.
L.10.4.4.5.2 Verify the capability of the NCS to achieve a NICMOS Cold Well
temperature (as measured by the 1-1 temperature sensor) of 77+/-1 degrees Kelvin
(nominal 77.15K) and maintain it within 0.1K.
L10.4.4.5.3 The NICMOS cooldown profile shall be characterized.
L.10.4.4.6 NICMOS/NCS calibration and Performance Requirements
L.10.4.4.6.1 The temperature of each NICMOS detector, along with its range of
variation and the timescale of variation, shall be determined. Detector temperature
stability shall be characterized over periods of 60 sec, 2000 sec, 24 hours and 30
days using available temperature sensors and temperature from detector bias.
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ERO Program
L.4.5.6
•
HST
MOSES
L.10.4.6 Early Release Observations. SMOV activities shall
include early release observations with at least the COS, WFC3,
STIS, and, if restored, ACS science instruments.
– The resulting science data products shall be released into the public
domain to demonstrate the improved/restored HST capabilities.
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