Progress Report

Geo-CAPECoastal Ecosystem Dynamics Imager

(CEDI)IRAD Repackaging Study

Jason Budinoff / GSFCCathy Marx / GSFC

May 12, 2011

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Coastal Ecosystem Dynamics Imager (CEDI) Block Diagram – IDL Baseline

Scan Mirror

Primary Mirror

Telescope “Aft”Optics

External Baffle

Enclosure

Optical Bench

Band 2(600-900 nm)

SIR

U Star Trackers (3)(orthogonally mounted)

Aperture Cover (closed during solar cal)

Band 1 (345-600nm)

SWIR Band

Slit

MCT H2RG2Kx2K

HyVISI TCM8050ACustom 1K x 2K

HyVISI TCM8050ACustom 1K x 2K

Calibration SourceThru-hole

Aperture Door Launch Lock

Detectors

• Volume - 7.5 m3

• Mass - 621.4 kg• Power - 392 W

I n t e g r a t e d D e s i g n C a p a b i l i t y / I n s t r u m e n t D e s i g n L a b o r a t o r y

GEO CAPE Study Week: 1/25 – 1/29/10Presentation Delivered: Jan 29, 2010

Use or disclosure of this data is subject to the restriction on the title page of this document

Mechanical Systems, pFinal

Aperture & Calibration Covers Opened

2-Sided Diffuser plate

Scan mirrormechanism

Solar Calibration View

Lunar Calibration & Nadir Science

Views

Why?

•Desire to reduce instrument volume to allow payload to be hosted on other missions

•“Minimally acceptable scientifically viable mission”….help to define this from the bottom up

•GEO-CEDI (IDL) at 7.5m2 too large to allow hosting on some platforms

•Study will evaluate architecture & packaging trades to reduce volume.

Volume Comparison

GEO-CEDI (IDL)7.5 cubic meters

GEO-MDI15.3 cubic meters

GEO-CEDI (IRAD)

4 cubic meters?

Trade Space

•The merit function is lowest volume, then lowest cost.

•Several parameters will be traded:1. Alternate optical packaging, Eff F/#,

folding, etc.2. Reduce gimbal size, alternate gimbal

architectures3. PPS / Jitter control implementation4. Alternate calibration schemes5. Primary Mirror scaling

• Some parameters will not be traded:1. Instrument architecture (Offner Relay slit

spectrograph)2. Spectral range and channel count

Gimbal

•Traditional elevation over azimuth type is baseline

•Evaluate flexure suspension XY scanner; analogous to large, “slow” steering mirror

•Evaluate transmissive cal with XY scanner only– Trade large air gap voice coils vs.

limited angle torque actuators

Alternate Optical Packaging

•Faster telescope•“out of plane” folding options to enable more space efficient packaging– Additional fold optics required– Additional optics (periscope/K

mirror) may be required to maintain slit orientation after folding

Current “IDL” layoutshown

Out of Plane Layout

Channel 1 HyViSi ROIC

345 – 600 nm

Channel 3 H2RG

1225-2160 nm

Channel 2 HyViSi ROIC

600-1100 nm

120mm FSM in

periscope

Slit channel

1+2Slit

channel 3

Calibration

•Specular calibration– IDL concept has

deployable calibration assembly, and required 3 mechanisms for 2 specular targets

•Transmissive calibration?

•Can we reduce number of calibrators?

Diffuser Plate Select

Mechanism

Double sided diffuser

Cover Mechanism

Launch Lock

Precision Pointing System (PPS)

• Add the JHU/APL PPS which utilizes FSM+star tracker+inertial reference (gyro) system to increase S/N, cancel S/C and self jitter– Coupled with scanning gimbal

• How do I get smaller by adding more components?

Alternate Layout

Future Work

•Complete mechanical sizing trade

•Add structural, thermal, optical bench detail

GEO-CEDI (IDL)7.5 cubic meters

GEO-MDI15.3 cubic meters

GEO-CEDI (IRAD)

<7.5 cubic meters

Still have a way to go!