SSSC/SITR: FORCAST

SSSC/SITR: FORCAST

December 11, 2008

Cornell University

Herter

11-Dec-08 2

FORCAST Description

• Facility Instrument• Dual-Channel 256x256 Camera

w/ Si BIB arrays 5-25 m with Si:As array 25-38 m with Si:Sb array

• 0.75 arcsec/pixel giving a 3.23.2 arcmin FOV

• Selectable Filters in 5-38 m range

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FORCAST/SOFIA Early Science Goals

• Perform demonstrative science observations• Emphasize unique capabilities of SOFIA/FORCAST

Observations at 30 – 40 µm High spatial resolution in the mid-IR (2″ - 4″)

• Build collaborations between the science instrument team and external investigators

• Bridge SOFIA observations with Spitzer observations Follow-up of regions that are too bright for Spitzer Follow-up of Spitzer objects with higher spatial resolution

• Prime Science Objects Winter/Spring: Orion Summer: Galactic Center, M17

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2008 2009 20102007

GIRRground integration

early science flights

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D

Early Science Timeline

• 10/08 Pre-ship Review• 01/09/09 Ship to Palmdale• 01/29/09 Ground installation

(on plane through 03/31/09)• 05/25/09 Short Science Flights

(also includes facility checkout)

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Detailed Timeline & Personnel loading

Dates Personnel Tasks

01/09 Ship

01/14 Arrival of instrument

01/14-21 geg,cph,ja,tlh Unpack & cool down instrument

01/22-28 geg,cph,ja,tlh,jmdb Baseline testing & margin

01/29 geg,cph,ja,tlh,jps,jmdb Install on plane

02/02-12 jps MCCS checkout

02/13-27 geg,cph,ja,tlh,jps,ldk,jmdb Line ops

02/28-03/31 ja,tlh,jps,jmdb,tn (as needed) Line ops interleaved with door tests

05/25-… geg,cph,ja,tlh,jps,ldk,gjs,tn,jmdg (not all fly at once)

Commissioning and science flights

Note: Normal procedure is to allow two weeks before installation for unpacking, cool down, and checkout. This allows time for another warm up and cool down in case there are any issues.

11-Dec-08 6

HighlightsMechanical: May adjust array positions after current cool down

Detectors: Lowered dark current in SWC array Testing fix for LWC array this cool down

Optics: Warm alignment of optics – (saw some vignetting cold) New dichroic same as old (hoped for better)

Electronics: FPGA code re-written: gets rid of sporadic timing bug and allows

implementation of fast reads for facility checkout

Software: Will be testing image motion compensation on this cooldown

Quick look: Keller continued work on updated pipeline and quick look software

Documentation: Have drafts of everything – but concerned about getting this done

System Testing: Lab testing shows S/W & H/W is robust, no mechanical or software

problems

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Status chartCategory Tech. Cost Schedule Comment

a. Cryostat No problems

b. Optics CsI window replaced, new dichroic installed

c. Detector New array in work (not for early science).

d. Electronics New preamps working

e. Software No known issues (some things to test)

f. Opto-mechanical system Co-align arrays after next cool down

g. Airworthiness Still need to complete

h. DCS

j. Documentation More to do

k. Commissioning Plan Progressing on schedule

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Issues and MitigationsIssue Sev’ty Description Imp’t Mitigation Who

AW minor getting airworthiness sign-off completed

sched geg

docs minor completing requested documentation

sched Relax some req’mts on delivery until later, help from project

geg,jda

dichroic major performance is lower than desired

sci. Observe with only one channel at a time

jda,tlh

filters major 38 um throughput low (due to dichroic!)

sci. Operate with reduced sensitivity, Lakeshore filter?, try MgO at detector as blocker

jda

IMC major Image motion compensation performance

sci. Test in lab and line-op (only applies to bright sources)

jps

• Severity Levels: Critical (instrument at risk), major (instrument functionality at risk), and minor (no loss of functionality)

• Impact can be on science, schedule, and/or budget

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Wavelength (microns)

Barr 2 (cd20) Barr 3 (cd28)Barr 2 (cd26) dichroic (FTS)Barr 2 (cd28)

FORCAST Dichroic• 2nd gen. dichroic tested (Barr 3)

CdSe and/or PbTe coating on Si Substrate• Performance same as previous one (Barr 2)

Above: dichroics before and after mounting

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Budget Status

• FY08 budget Original allocation – $1320K

• Expenditures No additional funds necessary

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Galactic Center Flight Plan

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FORCAST GC Fields

• 3 flights, each with 2 hrs on GC; observations at 24, 30, & 38 m• t_exp = 60 s, 75% efficiency, asymmetric chop w/ off-source nod

MIPS 24 m map w/ MSX 21 m for saturated areas

Working on more pessimistic plans and identifying chopand nod fields.

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Galactic Center Flight Plan

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Are We Ready?

• FORCAST is working Mechanisms and software appear very robust

• Funding risks Current budget is adequate

• Technical items in work (test this cool-down) New FPGA code Shift and add

• Driven by documentation – not technical issues• Detail planning almost complete for Galactic

Center observations

11-Dec-08 15

Contingency Plans

• What we would like to do if flights are delayed –

• Improve on “38 m” throughput Dichroic is our blocker Test MgO filter at “detector” (get really cold) Lakeshore is now producing long wavelength filters –

fabricate and test

• Optimize data acquisition Implement/try scanning rather than chopping for

increased efficiency