TIPS Meeting

TIPS Meeting

1. Observing Solar System Objects with JWST Ed Nelan

2. COS - Updates on COS Development Ken Sembach

3. NICMOS Status Tommy Wiklind

Next TIPS Meeting will be held on 16 January 2003.

19 December 2002, 10am, Auditorium

Observing Moving Targets with JWST

Ed Nelan

TIPS

Dec 19, 2002

Observing Moving Targets with JWST

Ed Nelan

TIPS

Dec 19, 2002

Ron Henry, Wayne Kinzel, Andy Lubenow, Knox Long, Vicki Balzano, Larry Petro, John Isaacs, Mark Abernathy,

Rusty Whitman, Bill Workman

Moving Targets

• Observations of moving targets with JWST is not part of the baseline plan. – Currently, there is no requirement for JWST to track a moving target

• The STScI proposal for the JWST Science & Operations Center (S&OC) does not include support for observations of moving targets.

• Science Working Group's interest in Solar System objects motivated a study by STScI to estimate the cost to the for supporting such observations.

Moving Targets

• Cost estimates in this study are for the Ground System (S&OC), i.e., STScI, only.

• Cost for flight software development not included. – We did not investigate if JWST can track moving targets, or the cost in

doing so (TRW)

– We did not estimate the additional cost for FGS FSW (CSA)

• Can the Science Instruments observe the bright planets?– We did not address the cost for SI modifications (SI teams)

Moving Targets

• Moving Targets are Solar System bodies:– Kuiper Belt Objects– planets– moons of planets– asteroids– comets

• Compared to stars, they are nearby, and they move – JWST parallax

– ephemeris

Moving Targets

Outline of this presentation:

• Why observe moving targets with JWST ?

• What angular rates might be encountered?

• Costs:

– Observatory efficiency, scheduling

– Operations, proposal preparation, planning & scheduling ($)

– Software development, I&T, maintenance ($$)

Why Observe Moving Targets?Shoemaker-Levy 9

Why Observe Moving Targets?Shoemaker-Levy 9 and Jupiter Impacts

Why Observe Moving Targets?

• Between 1994 and 1996 ~35% of all HST public out reach releases involved Solar System observations.

• But only ~2% of the HST program was dedicated to Solar System observations.

What’s involved in

Moving Target Observations? • Fixed targets (stars, galaxies, e.g.) are stationary with respect to the

guide star.

• A Solar System object moves with respect to a guide star

• Proposal Preparation, Planning & Scheduling:– Ephemeris– JWST parallax– Tracking.

• Complicates selection of the guide star

Fixed Target Observations

ScienceInstrument

FGS

*

*

Fixedtarget

Moving Target Observations

ScienceInstrument

FGS

*

*

Movingtarget

*

At what angular speeds do

Solar System bodies travel?

From J. Nella,JWST kickoff Meeting, 10/23/02

Angular rates of Neptune within JWST FOR

1 m

as /

sec

Angular rates of Jupiter within JWST FOR

5 m

as /

sec

Angular rates of Mars within JWST FOR

25 m

as /

sec

Angular rates of selected objects within JWST FOR

ObjectMin. Rate(mas/sec)

Max Rate(mas/sec)

DistanceTraveled in 10hrs at Min Rate

(asec)

Time to Travel 1’at Max Rate (hrs)

Mars 2.5 28.6 90.0 0.6Jupiter 0.070 4.5 2.5 3.7Jupiter,Io 0.004 10.2 0.14 1.6Saturn 0.040 2.9 1.4 5.7Uranus 0.020 1.4 0.7 17Neptune 0.004 1.0 0.14 24Pluto * 0.160 1.0 5.7 24KBO 0.002 0.5 0.07 48

* Includes motion about Pluto-Charon barycenter

Moving Target Observations may requirelong guide star track lengths

ScienceInstrument

FGS

*

*

Movingtarget

*

Moving Target Observations may requireshort guide star track lengths

ScienceInstrument

FGS

*

*

Movingtarget

*

Proposal Preparation, Planning and Scheduling

• The position of a Solar System object on the celestial sphere as seen from JWST will depend upon the the spacecraft’s position in its orbit about L2.– Orbit has a radius of 800,000km– Period of about 120 days.

• S/C’s predicted position will be uncertain by TBD% when forecast one year in advance (proposal preparation time). – Station keeping maneuvers difficult to predict.– Implications for S&OC’s generation of LRP.

• To investigate, we assumed 10% ephemeris uncertainty.

JWST in L2 Orbit

gs1

gs2

JWST in L2 Orbit

gs1

gs2

JWST in L2 Orbit

gs1

gs2

JWST in L2 Orbit

gs1

gs2

JWST in L2 Orbit

gs

Not a problem with HSTin low orbit, Earth’s ephemeris is well known.


ObjectPositionalUncertainty(asec)

Jupiter 24

Saturn 13

Uranus 5

Neptune 2

Pluto 1

KBO 0.7

Uncertainty of a Solar System object’s position as seen by JWST due to a 10% error in spacecraft’s one year predicted ephemeris.


• If bad pixels in FGS cause loss of lock on guide star:– need an accurate ephemeris to verify the path of a guide star across the

FGS while JWST tracks target is free of bad pixels.

• If the FGS can guide across bad pixels:– the uncertainty of the JWST predicted ephemeris is unlikely to present a

major problem (proposals can be flight ready many months in advance)

• Uncertainty in long range forecast of spacecraft ephemeris might delay final selection of a guide star until a few months before observations occur. Impacts LRP.

Observatory Efficiency, Event Driven Schedule

Plan window

Visit duration

flexible

constrained

Visit with long plan windowHDF

Visit with short plan window1.5 hours after SL-9 Impact

JWST Event Driven Schedule

Will observations of moving targets cause a loss of observatory efficiency?

• Observations will execute as visits within plan windows.

• Plan windows will overlap in time.

• Each plan window contains only 1 visit.

• Ideal Plan window is long compared to the visit duration.

• Visits execute at the earliest time possible.

• This approach minimizes gaps in observatory activities


• Overlapping Plan windows allow observations to execute according to events, and not be restricted to absolute times.

Visit 1

Visit 4

Visit 2

Visit 3

time


• If visit 2 fails, visit 3 executes early. No idle gap, observatory efficiency preserved.

Visit 1

Visit 4

Visit 2

Visit 3

time



Visit 1

Visit 4

Visit 2

Visit 3

time



Visit 1

Visit 2 fails

Visit 3 executes early

time

Visit 4 executes early


• When time constrained observations populate the schedule, loss of observatory efficiency can result if failures occur

Visit 1

Visit 4

Visit 2

Visit 3

time



Visit 1

Visit 4

Visit 2

Visit 3

time



Visit 1

Visit 4

Visit 2

Visit 3

time


• When time constrained observations populate the schedule, loss of observatory efficiency result when failures occur.

Visit 1

Visit 4

Visit 2

Visit 3

time

gap

Distribution of target-local HST plan windows for Solar System targets, 2000-2002

Visit with short plan window1.5 hours after SL-9 Impact

Visit with long plan windowSaturn


Observations of most Solar System objects can be scheduled when required tracking rates are very low.

• If guide star availability is the only constraint, visits can have long plan windows, and flexible scheduling.

• If target-local considerations determine plan window, restrictive scheduling results.

– Visits cause loss of efficiency when visits upstream in the queue fail. Same as time constrained observations of fixed targets.

• Degradation of observatory efficiency due to Solar System observations not expected to be significant.


Suppose all visits to all targets are of the same length and

– JWST spends 3% of its time observing solar system targets,– And 20% of these observations are time constrained,– And only 10% of all observations upstream in the queue (including fixed

targets) fail.

• Then the loss of observatory efficiency due to time constrained (Solar System and fixed target) observations is, assuming all visits are of the same length;

0.03 0.2 0.1 = 0.0006 = 0.06 %

Proposal Preparation, Planning and Scheduling Ascending levels of complexity for observing moving targets

Moving TargetEnhancements

Object Position TrackingAdvancedScheduling Ground

SystemFlight

Software

Star, Galaxy R.A., Dec no year no no

KBO Ephemeris no year yes no

Slow < μ0 Ephemeris no manymonths yes no

Fas t > μ0 Ephemeris yes months yes yes

Comets OrbitalElements yes Weeks,

days yes yes

Cost to S&OC for Observing Solar System Bodies

• To facilitate costs analysis:– adopted an operations concept– identified requirements levied on the ground system and flight software to

implement concept.– estimated $$ cost to meet the requirements.– estimated the cost for daily operations.

• The $$ cost to the S&OC is dominated by software development needed for the proposal preparation, planning, and scheduling systems.

Observing moving targets with JWSTConcept Assumptions

• All observatory level restrictions applied to fixed targets apply to moving target observations.

• Science instrument modes and target acquisition schemes used for fixed targets will suffice for moving target observations.

• JWST can track targets using an ephemeris.

• Only one guide star used for a visit. It shall be within the same FGS detector for the duration of the plan window.

Observing moving targets with JWST

• Concept supports observations of any moving target. Flight software and hardware set the limits.

• Concept is similar to HST approach, but is consistent with event driven schedule architecture.

• Concept is not optimized for observations when the guide star availability time is less than the time required to gather the science data (fast comet).– Get science by scheduling multiple visits with short plan windows, each

with new guide star. – Operations impact might be acceptable if instances are rare.


• For economy we assumed maximum re-use of the HST moving targets ground system (APT, MOSS)– ~500,000 lines of code!!!

• Concept results in ~12% increase in the size of APT, the Planning & Scheduling System, and the Guide Star Selection System.


Summary from the S&OC perspective.

• Observing Solar System objects with JWST will be easier than with HST (L2 vs low Earth orbit).

• Time constrained observations of Solar System bodies are not likely to significantly reduce observatory efficiency (requirement is > 70%)

• Software for PP&S and GS selection system increases in size by ~12%

over that needed for observing fixed targets.


• Cost to S&OC for software development, maintenance, I&T and 2 years of operations is estimated to be $2.7M– 5% increase in the baseline (fixed target) proposal.

• Afterwards, cost for yearly operations ~ $250K.– 2% increase for daily operations.

• Total cost to the project can be determined when flight software & hardware impacts are considered.

• Will it happen?– ????

Why, or Why Not, Observe Moving Targets?Shoemaker-Levy 9

TIPS Meeting






SPACETELESCOPESCIENCEINSTITUTE

Operated for NASA by AURA

An Update on the COS Development Status

TIPS19 December 2002

COS Optical Layout

OSM1positions 1 of 4 optics2 degrees of freedom

(rotation, focus)

OSM2positions 1 of 5 optics1 degree of freedom

(rotation)

Calibration Platform4 lamps, 3 beam splitters

Aperture Mechanismpositions 1 of 2 Apertures

2 degrees of freedom(x & y translation)

FUV Detector Head (DVA)

NCM2(Collimating mirror)

NCM3a, 3b, 3c(Focusing mirrors)

CalibrationFold Mirror

External Shutter(not shown)

Cosmic Origins SpectrographHubble Space Telescope

NUV Detector(MAMA)

COS Instrument Timeline

• N2 purge testing / alignment completed at Ball – test is not designed to confirm focus/spectral resolution

• Instrument being installed in enclosure • Initial delivery to GSFC in late February 2003

– EMI and acoustic testing followed by mini-functional

• Thermal balance and science calibration in vacuum will occur in late April through early June 2003

• Final instrument delivery to GSFC in June 2003

COS under N2 purge incleanroom at BATC

Sample G285M Science/Wavecal

• Wavecal – 3 bright stripes on left.

• Science – 3 weaker stripes on right.

• The sources of the glints have been identified and remedied.

Wavecal Science

glint

NUV G285M PtNe Wavecal Spectra - N2 Purge Data

Single grating tilt yields 3 stripes

ResolutionR ~ 20,000

NUV G230L PtNe Wavecal Spectra - N2 Purge Data

Wavelength (Å) Three grating tilts required to cover the full range shown

Resolution ~ 1.2 Å

FUV G160M PtNe Wavecal Spectra - N2 Purge Data

COS Instrument Status (FUV)

• All optics installed and aligned• FUV-01 flight detector currently installed• FUV-02 spare detector undergoing final

acceptance/qualification testing• Team may propose a swap of spare and flight if

spare has significant performance advantages over FUV-01; recommendation awaiting outcome of FUV-02 testing over the next 2-4 weeks

COS Instrument Status (NUV)

• Flight detector (NUV MAMA) installed• All optics installed and aligned – small alignment

errors detected during N2 purge testing have been corrected– Source of glint identified– Camera optic aligned– OSM1 flatfield tilt position verified

COS Instrument Status: Current Issues

• FUV detector swap? FUV02 (currently designated as spare) may provide higher quantum efficiency, but needs consideration of other qualities (flat field, background, etc.): decision TBD– FUV02 vacuum leak fix corrected with elliptical O-ring– Door mechanism operated >40 times– Still needs final vibe and thermal vacuum tests

COS Performance (FUV)

COS Performance (NUV)

FUV01 and FUV02 Quantum Efficiencies

FUV01FUV02

FUV02 / FUV01 QE Comparison

COS Instrument Status: Current Issues

• Manufacturing flaw caused the D2 lamps to fail under vibration– Source of problem identified– New lamps manufactured (two not suitable)– Vibe and TVac tests ongoing (look good)

• Two lamps passed random vibe and sine burst tests• Being installed in flight housings

Calibration Platform Random Vibration Test

STScI Ground System Development

Phase 1 (1/1/00 – 6/30/00) Macro Development ReconfigurationsPhase 2 (7/1/00 – 12/31/00) NUV Timetag Mode + Darks FUV Timetag Mode + Darks Phase 3 (1/1/01 – 6/30/01) FUV & NUV Accumulation Science Exposures FUV & NUV Target Acquisition Exposures FUV & NUV Target Peakup ExposuresPhase 4 (7/1/01 – 12/31/01) Aperture Alignment Exposures OSM1 Focus Alignment Exposures OSM1 Rotation Alignment Exposures OSM2 Rotation Alignment Exposures FUV & NUV FP Split Exposures

Phase 5 (1/1/02 – 6/30/02) FUV & NUV GO Wavelength Calibration Exposures FUV & NUV Flat Field Lamp Calibration Exposures FUV & NUV Automatic Wavelength Calibration

Exposures SAA Contours

Phase 6 (7/1/02 – 12/31/02) SMGT Preparations SMOV Special Commanding FUV & NUV Anomalous Recovery FUV & NUV Initial Turn-on FUV & NUV BOP Target Screening

Phase 7 (1/1/03 – 6/30/03) FUV & NUV Lifetime Adjustments Coordinated Parallels

• Phase 5 development completed– All science / calibration exposure development is now complete

– A few miscellaneous commanding activities remain

• Phase 6/7 development in progress– Bright object protection target screening in progress– Initial preparations for SMOV and thermal vacuum tests begun– Schedule being reworked in light of launch slip

STScI Ground System Development

STScI Thermal Vacuum Preparations

• Instrument Scientists and Data Analysts will support TVac activities at BATC– Assisting with science calibration plan

– Perform science calibration activities in May 2003

– Interested in helping? Contact Keyes/Sembach

• Data gathering– All COS thermal balance / science calibration data will be

permanently archived at MAST

– Data transfer document in preparation

COS Pipeline and Data Activities

• COS Pipeline (CALCOS)– Most modules are now complete

– Spectral merging procedures for FP-POS positions in progress

– Full testing to occur on integrated SI data

– Draft of ICD-47 (P. Hodge) is being reviewed

• COS Header Keywords– Standard header keyword selections/definitions for science and ACQ

exposures completed

– Established COS association requirements

– Keyword “dictionary” in progress

STScI User Support• COS Instrument Handbook

– Development to begin in Spring 2003

• COS exposure time calculators– Spectroscopic ETC and target acquisition ETC are in preparation

– Now due January 2004

• STScI Instrument Division COS Staff– Keyes, Sembach, Leitherer, Friedman, McMaster

• COS website– http://www.stsci.edu/instruments/cos

– to be “zoped” early next year

http://www.stsci.edu/instruments/cos



TIPS Meeting






NICMOS StatusDecember 2002

1. Overview

2. Dewar Temperature Adjustment

3. HST Calibration Work Shop

4. Science (Mike Corbin)


NICMOS is operational and is functioning according to expectations (better instrument than in Cycle 7)


Updates & News

NICMOS SMOV programs essentially completed (coronagraphy performance moved to Cycle 11 calibrations)

GO science programs started June 2002

Regular calibration programs are running

New Instrument Handbook ready

NICMOS is operational and is functioning according to expectations (better instrument than in Cycle 7)


Special calibration & test programs

Adjustment of the Pupil Alignment Mechanism no movement since Cycles 7 & 7N

Linearity measurements done but not yet ready for CDBS

High S/N flat fields done

New ‘grot’ and bad pixel masks done


Calibration Plans

Temperature monitoring continuously Multiaccum darks monthly Focus stability monthly/bi-monthly Photometric stability monthly

Dark Generator Tool Sosey executed/DRIP Intra-pixel sensistivity Mobasher executed/DRIP High S/N capability Gilliland executed/DRIP Polarimetry calibration Hines first epoch/waiting 2nd

Grisms calibration Thompson completed

One time programs

Monitoring programs

DRIP = Data Reduction In Progress


NIC1

NIC2

NIC3

Focus monitoring duringCycle 7, 7N and post-NCS


On-going studies

post-SAA Cosmic Ray Persistence Removal

Absolute DQE measurement

Zero-point verification/photometric calibration


Dewar Temperature

The NICMOS detectors are sensitive to temperature variations

Temperatures are measured at the Neon inlet and outlet (72.4 K)

NIC1 mounting cup temperature set point is 77.1 +/- 0.1 K buthas been slowly increasing during the last ~4 months



Dewar Temperature

The temperature increase is most likely due to parasitics because of the approaching warm season.

A decision to increase the NCS’s compressor speedto lower the temperature 0.05 K has been taken bythe NICMOS Group and forwarded to GSFC.

A further change in compressor speed when the coolerseason starts (April/May) is foreseen.

The compressor speed change is relatively small(~10 rps).


HST Calibration Work ShopNICMOS contributions

NICMOS Status D. Calzetti

The NICMOS Revival: Detector Performance in the NCS Era T. Böker

Photometric Calibration of NICMOS M. Dickinson

NICMOS Grism Performance in the Post Ice Age Era R. I. Thompson

Coronagraphy with NICMOS G. Schneider

Polarimetry with the NCS-enabled NICMOS D. Hines

NICMOS Cycle 10 and Cycle 11 Calibration Plans S. Arribas

NICMOS+NCS Era Darks L. Bergeron

The NICMOS Cooling System: Technology in the Service of Science T. Böker

Removal of post-SAA persistence in NICMOS data M. Dickinson

Post-NCS NICMOS Focus and Coma Analysis E. Roye

Combining NICMOS Parallel Observations A. Schultz

Pushing NICMOS Cycle 7 Calibrations M. Silverstone

NICMOS User Tools an Calibration Software Updates M. Sosey

TALKS POSTERS


SUMMARY

NICMOS is fully functional and operates accordingto expectations

Calibration programs are up and running

NCS compressor speed needs to be adjusted in order to keep the detectors at a constant temperature

TIPS Meeting






Documents

TIPS Meeting