SSSC/SITR: FORCAST

September 29, 2009

Cornell University

Adams/Herter

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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

FORCAST Trimester Review

Foldmirrors

Collimatormirror

SOFIAFocal plane

Cryostatwindow

FPA

Camera 1

Camera 2

25 mm

FORCAST Optical Raytrace

f/20

f/5.5

Lyot stop (pupil)

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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

• Selected Early Short Science Objects Winter/Spring: Orion Summer: Galactic Center, M17

FORCAST Trimester Review

Early Science Filter Configuration

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Position Filter Wheel

SWC LWC

FW 2 FW 1 FW 1 FW 2

1 (Home) OPEN 24.4 m (R=7.5) 38.0 m (R=8.8) OPEN2 5.3 m (R=33) 19.5 m (R=3.8) OPEN 30.6 m (R=5.7)3 6.3 m (R=48) OPEN 33.4 m (R=18) Grism 5 (R=140)4 6.6 m (R=34) 8.6 m (R=42) ND 34.8 m (R=8.3)5

7.6 m (R=15) 11.0 m (R=12)Door Occulting Mask

Door Occulting Mask

6 ND 11.28 m (R=56) 11.8 m (R=16) Grism 6 (R=250)

FORCAST Trimester Review

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2008 2009 2010

Preship Review

Ground integration

Short 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

Early Science Timeline

• 10/16/08 Preship Review• 12/09 Ship to DAOF; Post-ship checkout• 1/10 Ground installation• 2/1/10 Lineops #1• 3/4/10 First Light Flight• 7/6/10 Short Science Flights

(also includes facility checkout)• 12/7/10 Start Basic Science Flights

J F M A M J A S O N DJ

Ship to DAOF

Basic science flights

First light flight

FORCAST Trimester Review

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Detailed Timeline & Personnel LoadingDates Personnel Tasks

js MCCS Checkout

Mid-12/09 Ship

Mid-12/09 Arrival of instrument

Mid-12/09 geg,ch,jda,tlh Post-ship operations, warm test, leak check

1/10 geg, ch Cooldown

1/10 geg,ch,jda,tlh,jmdb Baseline testing & margin

1/10 geg,ch,jda,tlh,js,jmdb Install on plane

2/1/10 geg,ch,jda,tlh,js,ldk,jmdb Hangar/Line ops (9 nights; 5 contingency)

3/4/10 tlh,js First light flight

7/6/10 geg,ch,jda,tlh,js,ldk,gjs,tn,jmdb (not all fly at once)

Short science flights

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Line Ops Plan

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Test Name Description Mode

FOR-LO-1 Alignment of FORCAST to TA STARE

FOR-LO-2 SMA Focus Sequence STARE

FOR-LO-2a Occulting Masks Test STARE

FOR-LO-3 Ground Boresight Determination STARE

FOR-LO-4 TA Emissivity STARE

FOR-LO-5 Chop and Nod Settle Times; Image Quality C2N

FOR-LO-6 Optimum Chop Frequency C2N

FOR-LO-7 Plate Scale C2N

FOR-LO-8 Asymmetric Chop C2N

FOR-LO-9 Pointing Stability STARE

FOR-LO-10 Header Population for Acquired Data STARE, C2N, C2ND

FOR-LO-11 Data Reduction Pipeline Verification C2N, C2ND

FOR-LO-12 EMI/EMC Ground Testing STARE, C2N, C2ND

FOR-LO-13 Flight Scenario for Determining Frame Rates STARE

FOR-LO-14 Flight Scenario for Focus Determination STARE

FOR-LO-15 Flight Scenario for Standard Star Observations C2N, C2ND

FOR-LO-16 Flight Scenario for Science Object C2N, C2ND

FOR-LO-17 Flight Scenario for Science Object STARE (Scan)

FOR-LO-18 Flight Scenario for Science Object STARE (step)

Status ChartCategory Tech. Cost Schedule Comment

a. Cryostat No problems

b. Optics New Lakeshore Mesh Filters are installed and tested

Dichroic is still intact and performing adequately

Calibration Box is ready for end-to-end testing

c. Detector Backup 256x256 Si:Sb ready for flight

New Si:Sb larger format array in Fab (DRS Tech)

d. Electronics Both channels are operating synchronously

e. Software IMC is implemented; ready for testing CD36

f. Opto-mechanical system Pupils are aligned to simulated secondary

Arrays are co-aligned to center of field

FPA masks are installed

g. Airworthiness All documents are submitted

h. DCS

j. Documentation Some done, more to do

k. Commissioning Plan Pre-ship version to be released after cooldown 36

FORCAST Calibration Box Design

Layout in front of FORCAST

Illumination at the detector

• KRS-5 Lens images a black hot source onto the FORCAST Lyot stop• Chopper blade provides a background source

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Calibration Box

Lakeshore Mesh Filter Image Quality

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2 4 6 8 10

100

200

300

Distance (pixels)

Sig

nal

Radial Plot at ( 124.22, 124.52)

• Results are consistent with diffraction-limited performance

33.4 µm

Grid of 200 µm diam. Pinholes @ field stop (77 K)

0 2 4 6 8 10

100

150

200

250

Distance (pixels)

Sig

nal

Radial Plot at ( 125.22, 127.10)

0 2 4 6 8 10

150

200

250

300

Distance (pixels)

Sig

nal

Radial Plot at ( 125.04, 127.15)

38.0 µm24.4 µm

FORCAST Trimester Review

Dichroic Performance

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Barr 2 has better reflective performance

B Files 2568-2801R files 2411-2566

Barr3 Barr2 Mirror/open R/T_Barr3 R/T_Barr2SWC 11.0 3221 3689 4611 0.70 0.80SWC 11.3 2767 3336 4346 0.64 0.77SWC 19.5 3780 4195 4868 0.78 0.86SWC 24.4 1348 1627 1811 0.74 0.90LWC 30.6+ND2 1390 1405 3370 0.41 0.42

LWC 33.4 1865 1866 4351 0.43 0.43LWC 34.8 2499 2475 5126 0.49 0.48LWC 38.0 2064 2022 4958 0.42 0.41

Array Optimization

• Sb-083, 30.6 µm + ND2, Low Cap• Detectors are optimized for best S/N vs.:

• Detector bias • Well size• Frame time

• Determine trade-off between signal vs. dark current, hot pixels

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Budget Status

• FY10 budget Carry over of travel funds from previous year Delays will require an additional ~ $100k of support above current

allocation

• No future funding for larger format Si:As detector

FORCAST Trimester Review

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Are We Ready? Yes we are!!

• FORCAST is working Mechanisms and software appear very robust

• Technical things to do yet (no show stoppers) End-to-end testing of Calibration Box Testing of IMC (shift-and-add) Implement acquisition scripts for lineops flight scenarios Implement digital detector bias control

• Schedule risks None

• Early science planning underway for range of possible flight dates, e.g. Orion or Galactic Center emphasis

GC plan requires tweaking per new (June 2010) schedule for ESS Line Ops will test different observing strategies (C2N, Scanning, etc.)

FORCAST Trimester Review