TIPS/JIM
September 20, 2007
Agenda:
INS Division News (Kriss)
NICMOS Defocus Mode Status (Dashevsky)
An Overview of Recent HST Safings (Sembach)
The Cycle 16 Long-range Plan (Adler)
Next TIPS/JIM: October 18, 2007
1
Instruments Division News
09/20/2007
•
•
•
•
•
•
•
•
•
•
I’m pleased to announce that we have hired 3 new DAs:
To help with SM4 preparations for COS, Tom Ake will be joining us starting around
Nov. 1. Tom is a CSC employee who has worked on science operations for FUSE,
and many of you may remember him from IUE days.
Jay Anderson will join INS on the WIT team on October 1. Many of you know Jay as
an expert on astrometry and precision photometry, and he’ll be putting these skills to
good use as we plan for how to best carry out and calibrate JWST observations with
NIRCam.
HST news:
o WFC3 Thermal Vacuum testing continues. The planned 3rd session will
test the fix to the IR thermal control circuits.
o Teams are working hard on Activity Descriptions for SMOV. The internal
deadline is September 28, in preparation for a review at GSFC on Oct. 12.
JWST news:
o Kathy Flanagan has joined STScI as the new JWST Mission Office head.
Kathy comes to us from MIT, where she worked on several Chandra
instruments. Kathy has served and is serving on several top-level NASA
advisory committees, including the JWST Science Assessment Team.
o The conference “JWST and Concurrent Facilities” that many of us will be
attending next week will discuss the big scientific problems to be tackled
in the next decade. It should be fun!
Beta testing is in progress for the central storage system, with the ACS team blazing
the trail.
Advertisements for Visiting Scientist positions and term hires close September 30. I
have 10 applications in hand, but hear rumors of at least a dozen more that should
appear just before the deadline. Please offer last-minute encouragement to likely good
candidates that you know.
I’m happy to announce that we are in the last stages of this year’s appraisal cycle.
Thanks to the team leads for finishing all the written work in a timely fashion. After
we’re done, I’d welcome any feedback that you would like to offer on this year’s
process.
Kevin Lindsay has provided the following update from the INS Diversity, Culture
and Respect Working Group:
o The next INS pizza lunch will be October 25th, and will be $5 per
person...an email will be coming soon.
o The DA round table discussion has taken place, and was very productive.
o The Scientist round table discussion will be Thursday afternoon (today).
o We are still looking for volunteers/nominations for the remaining 4 round
tables: Advancement & Rewards, Project Assignments, Tolerance, and
Teamwork & Group-to-group interactions.
Finally, I’ve had no volunteers for helping to organize an INS picnic! Please let me
know if you’d like to help.
TIPS/JIM
September 20, 2007
Agenda:
INS Division News (Kriss)
NICMOS Defocus Mode Status (Dashevsky)
An Overview of Recent HST Safings (Sembach)
The Cycle 16 Long-range Plan (Adler)
Next TIPS/JIM: October 18, 2007
1
NICMOS
Defocus Mode Status
Ilana Dashevsky
(Commanding)
2
Team
•
Developers & Testers:
Colin Cox
Ilana Dashevsky
Tom Donaldson
Rob Douglas
Mark Giuliano
Tony Krueger
Matt Lallo
Jinger Mo
Karla Peterson
Christine Ritchie
Alan Welty

Engineering:
Morgan Van Arsdall (GSFC)
John Bacinski (GSFC)
Tom Wheeler

Planning & Scheduling:
George Chapman
Beth Perriello
Tony Roman

Science & Data Analysis:
Tommy Wiklind
Helene McLaughlin
Nor Pirzkal
Ron Gilliland
Eddie Bergeron
Anton Koekemoer
TIPS 20 September 2007
3
Goal

Improve & simplify process to defocus the
NICMOS detectors


Use Astronomer’s Proposal Tool (APT) and
standard proposal processing to request a nonnominal focus for a detector
Support planetary system investigations of
very bright stars (up to S/N ~10,000)

Detect spectral features in planetary atmosphere
using grism
TIPS 20 September 2007
4
STScI PR 2001-38:
“Astronomers
using NASA's
Hubble Space
Telescope have
made the first
direct detection of
the atmosphere of
a planet orbiting a
star outside our
solar system and
have obtained the
first information
about its chemical
composition.”
- Team led by D.
Charbonneau used
STIS
Ron Gilliland pioneered technique
using NICMOS to observe stars like
HD 209458
TIPS 20 September 2007
5
Rationale for Change

Old implementation required significant manual
intervention and checking





“Restricted” mode not intended for GOs
Specify defocus as a delta offset from nominal requires
expert knowledge
Mistakes may result in mechanism hitting hard stop
Number of GO requests to defocus detector 3
increased from one in 2003 to six in 2007
More requests expected

Defocus detector 1 (narrow band photometry)
TIPS 20 September 2007
6
Background

Pupil Adjust Mechanism (PAM) is used to provide optical
alignment for NICMOS science observations.




Maximum PAM Motion is +/- 10mm
Maximum Tip/Tilt +/- 1373 a-s
All 3 detectors were originally designed to share a common
focus
Deformation due to the dewar thermal short has resulted in
separate PAM focus positions:



PAM 1, 2 and 3 are the home locations corresponding to detectors
1, 2 and 3 respectively
PAM I is an intermediate position that results in acceptable focus
for detectors 1 and 2
PAM C is used for coronographic observations
TIPS 20 September 2007
7
Life Time Concerns Addressed

Tom Wheeler recently re-examined PAM usage & failure modes





12,533 PAM moves & 5,431,471 focus motor revolutions on orbit,
as of April 2007
Motor & gear-head assembly tested to ~3 billion motor revolutions;
never failed
Bellows assembly tested to 100,000 compression/expansion cycles;
never failed
Lubricant & other mechanical components have proven track
record in spacecraft
Component fatigue due to motor overheating



Engineers at Ball concluded that “fatigue is not a problem”
Mitigate in schedule by enforcing PAM cool-down periods
Monitor schedule for possible PAM motor overheating events
TIPS 20 September 2007
8
Implementation

New PAM out-of-focus positions




Detector 1: -3.0 mm (best focus at 1.8 mm)
Detector 2: -5.0 mm (best focus at 0.2 mm)
Detector 3: -0.5 mm (best focus at -9.5 mm)
More robust defocus commanding implemented

Command PAM to an absolute position


Flight Software verifies position and checks against soft stop
All front-end systems changes installed



APT, VTT, TRANS, Commanding, SIAF, Science Operations
Database, SMS Review Tool
APT Version 16.4
Phase II Proposal Instructions Eng. Version 16.1
TIPS 20 September 2007
9
APT Changes

New apertures for each detector to adjust the FOV
center for the out-of-focus motion


New exposure value for existing NICMOS Optional
Parameter


NIC1-FIXD, NIC2-FIXD, NIC3-FIXD
CAMERA-FOCUS = DEFOCUS
PI should consult with Instrument or Contact
Scientist

Available but Unsupported mode
TIPS 20 September 2007
10
APT Example
TIPS 20 September 2007
11
On Orbit Test


Verify that the new PAM locations produce
desired science data
Proposal 11335 consists of two orbits:


1st orbit repeats observations for HD 209458 (7.6
mag) using detector 3 and grism G141
2nd orbit repeats observations from the routine
focus monitor of an open cluster NGC-3603 to
verify defocus for all detectors using phase
retrieval
TIPS 20 September 2007
12
Status
2007

1st orbit executed on
September 13th


Brief analysis by Ron Gilliland
confirmed detector 3 defocus &
aperture were successfully
implemented
2nd orbit will execute
September 21st

new defocus
parameter
2006
old method
Defocus tested for all NICMOS
detectors
TIPS 20 September 2007
13
Results
Coming soon to a
TIPS near you ….
TIPS 20 September 2007
14
TIPS/JIM
September 20, 2007
Agenda:
INS Division News (Kriss)
NICMOS Defocus Mode Status (Dashevsky)
An Overview of Recent HST Safings (Sembach)
The Cycle 16 Long-range Plan (Adler)
Next TIPS/JIM: October 18, 2007
15
An Overview
of the Recent HST Safings
Ken Sembach
TIPS Presentation
September 20, 2007
16
ZGSP Safe Mode Entry

HST entered zero-gyro sun-point safe mode at ~7 PM EDT on August 31,
2007

Timeline of event












243/22:43:00 LOS
243/22:51:59 Enter orbit night
243/22:53:33 Two-Gyro transition to M2G mode
243/22:53:33 Type 2 vehicle slew (13 min 33 sec duration)
Gyro Bad Disparity count exceeded limit of 1500 counts
243/23:01:54 Two-Gyro configuration failed (Zero-Gyro Drift Mode – AD commanded
closed)
243/23:27:06 Enter orbit day - Sun Bright Object Protection failed
Begin Zero-Gyro control
243/23:31 Expected AOS
243/23:39 Acquired telemetry
244/03:51 Engineering data dumped from recorder
244/05:52 OR# 18123-1 Power on Gyro 6
TIPS 20 September 2007
17
Gyro #2 Failure

HST was preemptively placed in two-gyro mode in August 2005 to conserve
gyro lifetime

Gyro #2 failure


HST responded as expected
Eventual failure of Gyro #2 was anticipated


Most likely cause: flex lead failure





HST had reached approximate date of 50% probability of 4 working gyros
Corrosion of thin electrical wire (“traditional” flex lead, no silver plating)
Corrosion a function of current, diffusion rates, wire inhomgeneities
Had improved fluid and fluid fill process (pressurized nitrogen vs. air)
Restart of Gyro #2 was deemed infeasible (failure permanent)
Gyro #6 was powered on at ~2 AM EDT on 1-Sep-2007



Gyro #6 had been turned off early in its lifetime
Gyro #6 shows some bias drift (noise)
Gyro #6 bias is settling slowly (1-2 months expected)
TIPS 20 September 2007
18
Gas-Bearing Gyroscope
TIPS 20 September 2007
19
Gyro Status

Full complement of gyros (6) was replaced during SM3A in
December 1999

Gyro run times (31-Aug-2007)







G1
G2
G3
G4
G5
G6
45578
57315
33197
53505
16126
12547
hours
hours
hours
hours
hours
hours
-
operational, powered
failed, 31-Aug-2007, flex lead
failed 29-Apr-2003, rotor restriction
operational, turned off 28-Aug-2005
failed 28-Apr-2001, rotor restriction
operational, powered
All 6 gyros (3 rate sensing units - RSUs) are slated to be
replaced during SM4
TIPS 20 September 2007
20
Gyro Lifetime Estimates
Chart below shows approximate gyro failure probabilities assuming a gyro
failure in July 2007 (close to time of Gyro #2 failure)

1
0.9
SM4
0.8
Jul-2007
0.7
Availability
0.6
Feb-2011
Jan-2009
0.5
0.4
0.3
May-2008
0.2
0.1
0
Feb-2007
Feb-2008
Feb-2009
Feb-2010
Feb-2011
Feb-2012
Feb-2013
Feb-2014
Feb-2015
Feb-2016
Feb-2017
Tim e (calendar date)
1 or more operating gy ros
2 or more operating gy ros
3 gy ros (2 operating, 1 in-res erv e)
Predictions from Helen Wong (Aerospace Corp)
as communicated to Art Whipple (HSTP)
TIPS 20 September 2007
21
Impact to Science

Safing occurred near end of week (late Friday)

~25 orbits of science deferred (see Adler talk)

Health and safety SMS loaded 1-Sep-2007 (Saturday)

Science SMS loaded 2-Sep-2007 (Sunday)

All WFPC2



Time critical WFPC2 orbits from previous week rescheduled
No NICMOS orbits because of unrelated NICMOS safing event
Congratulations to entire team here and at GSFC on speedy recovery!
TIPS 20 September 2007
22
One-Gyro Preparations

One-gyro mode is in an advanced stage of preparation, work begun in
mid-2005

To be used only if necessary


Target availability should be similar to two-gyro mode
Jitter should be slightly larger than in two-gyro mode, but still very good
•

Initial PCS estimates indicate <10 mas persistent disturbance jitter (60-sec, RMS)
Power on Gyro #4 if either Gyro #1 or Gyro #6 fails prior to SM4

Gyro #2 failure has not significantly altered one-gyro work schedule

On-orbit test planned during week of 28-Jan-2008

External observations with WFPC2 and FGS
•
•


PSF width and jitter impact (Sirianni: 11077)
FGS astrometry (Nelan: 11078)
Pointing and control maneuvers (Reinhart: 11345)
Checkout similar to two-gyro mode checkout
TIPS 20 September 2007
23
NICMOS Safing

NICMOS entered safe mode at ~11 PM EDT on 1-Sep-2007




NICMOS was in SAA/Operate mode as a result of previous HST safing
No NICMOS activities at the time of event
HST was not in SAA at time of safing
HST power profile nominal at time of safing




Expected PDU3 current drop seen in response safing
NICMOS telemetry and NED telemetry prior to safing appeared normal
No out-of-family issues with ACS or WFPC2 at time of safing
Error: A/D FIFO empty prior to reading all expected data


Appropriate response is to safe instrument
Buffer read every 0.5 seconds

Many (tens of thousands) normal reads between HST safing event or two-gyro recovery and NICMOS
safing => unrelated events
TIPS 20 September 2007
24
NICMOS Safing (continued)

Cause: Single event upset (SEU) affecting the engineering data buffer, a CPU
register, or a memory location



NICMOS was brought up to SAA/Operate mode



Telemetry nominal
Normal engineering data process functioned as expected
Buffer box temperatures were raised to nominal values



“Verified” on VSTIF ops bench
Recommended action was to recover from safe mode
Had been running cold due to NICMOS inactivity
Brief transition to Operate and back to SAA/Operate to refresh buffer box telemetry
NICMOS science resumed with SMS loaded 9-Sep-2007
TIPS 20 September 2007
25
TIPS/JIM
September 20, 2007
Agenda:
INS Division News (Kriss)
NICMOS Defocus Mode Status (Dashevsky)
An Overview of Recent HST Safings (Sembach)
The Cycle 16 Long-range Plan (Adler)
Next TIPS/JIM: October 18, 2007
26
The Long Range Plan:
Cycle 16 update
Dave Adler – TIPS
September 2007
27
Outline





Current Cycle 16 LRP vs the Initial LRP
Impact of the Sept 1 safing
Cycle 16 tail
WFPC2 past SM4
Cycle 17 Post-SM4 testing
TIPS 20 September 2007
28
The Initial Cycle 16 LRP
Released 07.178 (6/27/07) – for the 07190 SMS
 4498 total orbits
Prime Instrument:*
WFPC: 2292 orbits
NIC: 1563 orbits
ACS: 608 orbits (1)
FGS: 216 orbits
* - some visits have more than one
instrument prime.
(1) – 23 orbits HRC/WFC prime not
yet converted
Breakdown by cycle:
Cycle 16: 3037 orbits
Cycle 15: 1402 orbits
Cycle 14: 59 orbits
Not in the LRP:
ToOs ~50 orbits
Cycle 16 cals: ~ 100 orbits
HOPRs (2.5%) ~100 orbits
TIPS 20 September 2007
29
The Current LRP
07253A - visits scheduled through 07.267 (9/23/07)

3764 total orbits
Prime Instrument:*
WFPC: 1752 orbits
NIC: 1455 orbits
ACS: 522 orbits (1)
FGS: 193 orbits
Breakdown by cycle:
Cycle 16: 2773 orbits
Cycle 15: 947 orbits
Cycle 14: 44 orbits
* - some visits have more than one
instrument prime.
(1) – 4 orbits HRC/WFC prime not
yet converted
TIPS 20 September 2007
30
Cycle 16 LRP - progress
LRP
built
Complete
through
Total
orbits
Jul 13
07.203
4470
3375
349
746
Aug 16 07.238
4052
3040
277
735
Sep 10
3764
2793
236
735
07.267
Through 08.220 – 08.255 –
08.220 08.255
09.068
SM4
TIPS 20 September 2007
31
Recent calendars





07239: pre-safing: 75 orbits
post-safing: 50 orbits
07246: pre-safing: 86 orbits
post-safing: 66 orbits
07253: 88 orbits
50% efficiency
07260: 91 orbits
54% efficiency
07267: 81 orbits
46% efficiency
TIPS 20 September 2007
32
Current LRP – full through SM4

SAA-free demanders vs SAA-hiders
Total orbits SAA-free demanders SAA-hiders
/per day
/per day
/per day
-------------- ------------------------- ------------Cycle 16:
~2779/ 8.7
1477/ 4.6
1302/ 4.1
(07.267-08.220)
Cycle 16 tail: ~877/ 4.1
564/ 2.6
313/ 1.5
(08.220-09.068)



We allocate two orbits/day for “unplanned” visits.
8.7 + 2 = 10.7 orbits/day = 75 orbits/week.
Slightly more than 2-Gyro average – Cycle 16 is full through SM4.
TIPS 20 September 2007
33
LRP example – hiders, free-demanders
SAA-free demander
SAA hider
Partial SAA hider
TIPS 20 September 2007
34
Current LRP – hiders vs free demanders
SM4
8/7/08
SAA-free
subscription
is low
total orbits
SAA-free
demanders
SAA-hiders
SAA-hiding
subscription
is full
Cycle 16 (nominal)
TIPS 20 September 2007
Cycle 16 tail
35
Plan Flexibility: hiders vs free-demanders
Previous Cycles:
 majority of programs were SAA-free demanders (which
can’t go in SAA-impacted orbits).
 fewer SAA-hiders (schedule in SAA-impacted orbits).
Cycle 16:
 Instrument compliment in Cycle 16 – higher percentage
of visits are SAA-hiders.
Since SAA-hiders can schedule in SAA-free orbits,
Cycle 16 has more scheduling flexibility.
TIPS 20 September 2007
36
Current plan – northpoint weeks
Weekly subscription depends
on timing of northpoint
TIPS 20 September 2007
37
2-Gyro orbit counts
2-gyro average – 73.5 orbits/week
3-gyro average (Cycles 12/13) – 81 orb/week
TIPS 20 September 2007
38
Impact of the recent safing

Gyro failure at 243:23.


NIC safing at 245:02.


Science recovery at 246:00; 25 orbits “lost.”
NIC science pulled off the 07246 SMS; net “loss”
of 20 orbits.
No science visits lost.

all 45 orbits were rescheduled on the 07246,
07253, and 07260 SMSes, or replanned for the
next few weeks.
TIPS 20 September 2007
39
Cycle 16 tail
The LRP > 08.255 (9/10/08: original SM4 date)





No Cycle 15 (or earlier) programs
No ACS contingency programs
No WFPC2 prime programs
Only one WFPC2 parallel program – 75 orbits – can’t
move earlier without oversubscribing other regions.
Some programs can be pulled forward if subscription
in the target region is low (i.e., “unplanned” visits
haven’t used it) and the program constraints allow it.
TIPS 20 September 2007
40
WFPC2 beyond SM4

One Cycle 15/ACS contingency program visit (2 orb)
has moved passed SM4 due to guide star problems.

With Neill Reid and Ken Sembach, used the following
criteria to decide which WFPC2 to move forward:

Programs that will be less than 10% complete at SM4:


Programs greater than 90% complete at SM4:


leave post-SM4 visits alone; they will be converted to WFC3.
leave post-SM4 orbits alone; program will be considered
complete. PI can appeal for reinstatement of orbits to TTRB.
Programs between 10-90% complete at SM4:

move forward if possible.
Moved 36 orbits forward; 132 orbits from 11 programs
remain.
TIPS 20 September 2007
41
Cycle 16: End of Cycle Details
• Instrument breakdown:
Instrument (prime)
FGS
ACS/SBC
WFPC2
NICMOS
Total
Orbits* (08.220-08.255)
Orbits* (> 08.255)
6
19
35
243
132
0
82
474
231 (1)
736
Notes:
* programs with plan windows ending in the specified region.
(1) 24 orbits have both WFPC and SBC prime.
TIPS 20 September 2007
42
Cycle 16: End of Cycle Details
• Large Programs:
Program/PI
orbits
allocated
completed/ 08.220 > 08.255
scheduled -08.255
11120 - Wang
144
0
0
0
11142 - Yan
150
0
34
75
11149 - Egami
72
0
0
62
11178 - Grundy
128
50
1
0
11202 - Koopmans
159
10
3
32
11210 - Benedict
63
10
1
0
11211 - Benedict
67
9
3
2
11236 - Teplitz
TIPS 20 September 2007
117
0
0
74
43
Cycle 17 Post-SM4 testing
Goal: Demonstrate that the ground system
functions on a representative sample of
post-SM4 HST proposals in 3-Gyro mode:






Proposal creation
Proposal implementation
Long Range Plan generation
Weekly science schedule generation
SMS generation
Mission Schedule/Command Load generation
TIPS 20 September 2007
44
Cycle 17 Post-SM4 testing: LRP


3-Gyro OBAD mode
830 external orbits:





220 COS
375 WFC3
225 NIC, ACS, STIS, FGS
Restricted to 07.260-07.330 – most visits
schedulable over full time frame.
Artificially restricted Plan Windows to provide a
good mix of visits for each test calendar.
Result: Spike worked fine. Distribution of SAA-hiders
and free-demanders is representative of a typical
operational LRP.
TIPS 20 September 2007
45
Cycle 17 Post-SM4 testing: Scheduling





Added science visits to a candidate list, scheduled
them.
Scheduled snaps using the normal process.
Scheduled parallel observations.
Selected guide stars.
Ran “non-continuity” (stand-alone) Science
Mission Specifications (SMS).
Results: Calendars with 80-90 orbits/week. SPSS and
SMS generation worked fine; no functional issues
identified in these systems with new instruments.
TIPS 20 September 2007
46
Cycle 17 Post-SM4 testing: Upcoming work

Generate LRP reports




Pending ASSIST DB updates.
Build “non-continuity” schedules, SMSes for the remainder
of the weeks in the DRM LRP.
Generate Mission Schedules/Command Loads
Report “final” status at DRM Working Group meeting on
October 17


Report identified problems/liens
Determine need for additional exercises
TIPS 20 September 2007
47