# Presentation: 846820

## OLI Overview and Status

**Edward J. Knight, Ph.D.**
**Landsat Science Team Meeting**
**7/15/08**

## Outline

**Instrument Overview**
**Subsystem Status**
**Preliminary Data**
**Conclusion**

## Instrument Overview

## OLI Maintains Landsat Legacy

**Landsat Continuity Mission demands**
**Accurate spectral and spatial information **
**Frequent synoptic earth views**
**NIST calibrated over time **
**Precise geo-referenced data **

| Band Name | Band (nm) | Bandwidth (nm) | GSD (m) | SNR |
| --- | --- | --- | --- | --- |
| Coastal/Aerosol | 443 | 20 | 30 | 130 |
| Blue | 482 | 65 | 30 | 130 |
| Green | 562 | 75 | 30 | 100 |
| Red | 655 | 50 | 30 | 90 |
| NIR | 865 | 40 | 30 | 90 |
| SWIR 1 | 1610 | 100 | 30 | 100 |
| SWIR 2 | 2200 | 200 | 30 | 100 |
| PAN | 590 | 180 | 15 | 80 |
| Cirrus | 1375 | 30 | 30 | 50 |

**Visible/NIR**

**SWIR**

**Key instrument parameters**
**Cross-track FOV ****	****185 km **
**S/C altitude****	****	****705 km**
**Geodetic accuracy* **
**Absolute ****	****	****65 m **
**Relative ****	****	****25 m**
**Geometric accuracy** **
**Absolute   ****	****12 m**

***No terrain compensation**
****w/ terrain compensation**

## Driving Performance Requirements

**Radiometric**
**Signal-to-noise radiometric stability****(16-day, 60 sec, 5 year)**
**Pixel-to-pixel uniformity**
**Absolute radiometric accuracy **
**Absolute radiance – 5%, absolute reflectance – 3%**
**Spectral**
**Spectral band edges and center wavelength tolerance**
**Integrated out-of-band (OOB) response****(<2%)**
**Spectral uniformity (FWHM) (± 3%)**
**Spatial**
**Edge response**
**Aliasing**
**Light rejection and internal scattering**
**Ghosting**
**Geometric**
**Band-to-band co-registration (4.5 m)**
**Absolute geodetic accuracy (65 m)**

| 

# | Minimum Lower Band Edge (nm) | Maximum Upper Band Edge (nm) | 

SNR at LTypical | 

SNR at LHigh |
| --- | --- | --- | --- | --- |
| 1 | 433 | 453 | 130 | 290 |
| 2 | 450 | 515 | 130 | 360 |
| 3 | 525 | 600 | 100 | 390 |
| 4 | 630 | 680 | 90 | 340 |
| 5 | 845 | 885 | 90 | 460 |
| 6 | 1560 | 1660 | 100 | 540 |
| 7 | 2100 | 2300 | 100 | 510 |
| 8 | 500 | 680 | 80 | 230 |
| 9 | 1360 | 1390 | 50  | N/A |

**OLI Band and SNR Specs**

## Baseline Design and Descriptive Block Diagram

**Pushbroom VIS/SWIR sensor**
**Four mirror telescope with front aperture stop**
**FPA consisting of 14 sensor chip assemblies, passively cooled**

## Key Technical Parameter (KTP) Performance Summary

**Meeting all key requirements with margin**
**Mass and power are reported for both current best estimate (CBE) and “mature” values, which include Ball Aerospace growth factors**
**“****Current Best Estimate” is the designer’s estimate**
**Mature mass / mature power reflects historical growth.  i.e., it’s contingency**
**Margin is low for coregistration simply due to an ‘allocation’ issue**
**Spacecraft predictions for attitude control exceed their requirements and have not been captured in the budgets yet**

## OLI One-Page Schedule

## Subsystem Status

## Flight Optics Are in Final Polishing Operations at Tinsley

**Flight Optics Are in Final Polishing Operations at Tinsley**

**Flight Secondary Mirror at Final Edging (now in edge polish)**

**Flight Quaternary Mirror**
**After Aspheric Shaping**

**Flight Primary Mirror**
**Prior to Final Polishing**

**Flight Tertiary Mirror Silvered for WFE Testing**

## Main Bench Assembly Takes Shape

**ATK technicians bond FPA bulkhead into bottom bulkhead as main bench assembly takes shape **

## Focal Plane Consists of 14 Modules

- Focal Plane Module

**Each Module contains Silicon and HgCdTe detectors mounted on a single readout chip (ROIC) **
**Spectral Filters above the detectors provide separation into bands**

## Engineering Model Focal Plane Hardware Looks Good

**Engineering Model Focal Plane Hardware Looks Good**

**HgCdTe Detectors**

**ROICs**

**VNIR Si PIN Detectors**

## Engineering Unit Electronics Boards Are Being Populated

## Thermal Control Design

**Thermal Control Design**

- FPA Radiator

- FPE Radiator

- Heat Pipe Support

- FPE Heat Pipe

- FPA Heat Pipes

- FPE

- FPA

- Support Truss

_**+X UP ORIENTATION**_

- Design integrated onto instrument

## Calibration Detailed Design Underway

**Calibration Subassembly Consists of Five Subassemblies **
**3 LightShade Assemblies**
**1 Diffuser Assembly **
**1 Shutter Assembly**

**Entrance**
**LightShade**

**Diffuser **
**Assembly**

**Aft **
**LightShade **

**Exploded View of Calibration Subassembly**

**Solar**
**LightShade**

**Shutter **
**Assembly**

**Stim Lamp Assemblies redesigned to increase emitted light and optimize monitoring diode position **

- Diodes view diffuser instead of housing wall
- No direct view of any lamps

**Calibration Detailed Design Underway**

## Ball Aerospace Algorithms Cover Both On-line and Off-line Processing

- LDCM CPF

- LDCM Archive database

**Retrieve Data**

**Prepare Ancillary Data for Input to Ball Code**

**L0 Image Construction**

**Parse Data**

- Radiometric Processing

- Geometric Processing

**Product Generation**

- Ball/LDCM
-  Archive database

- Evaluation of Results

- Ball Performance, off-line Analysis, Track and Trend Tools

- Update

- yes

- yes

- Stop

- no

**Data Ingest **

**Radiometric Processing**

**Geometric Processing**

**Product Generation**

**Ball Data Analysis System**

**LDCM IPE**

**Collaborative Decision **

**Ball Calibration Parameter Files (CPF)**

**Ball On-Line Processing**

**Ball Off-Line **
**Processing**

- Processing Algorithm

- Radiometric Algorithms

- Geometric Algorithms

## Preliminary Data

## HgCdTe SWIR Pilot Lot Material Meets Specifications for Quantum Efficiency

**Cutoff wavelength is high enough that we’ll have good response in the SWIR**
**Good QE**
**Good spectral flatness**

**              **

- 0

- 0.1

- 0.2

- 0.3

- 0.4

- 0.5

- 0.6

- 0.7

- 0.8

- 0.9

- 1

- 0

- 1

- 2

- 3

**Wavelength (um)**

**Relative Response / Photon**

- B07    2.49u

- B08    2.49u

- B09    2.49u

- B18    2.49u

- Line Diode  Cutoff

**SWIR 2**

## HgCdTe SWIR Material Exhibits Low Dark Current and Excellent Dark Current Uniformity

**HgCdTe SWIR Material Exhibits Low Dark Current and Excellent Dark Current Uniformity**

**Measurement Data on Pilot Lot Test Structures**

***Lower is better; values show meet dark current requirements***

**Median Leakage Current at 20 mV Bias **

**for Various Mini-arrays LDCM Pilot Lot 1 TSAs**

- 636735

- 636736

- 636737

- 636738

- 636739

- 636740

- 636741

- 636742

**TSA**

**Median Leakage Current (A)**

- D

- J

- L

## First Pass Spectral Filters Show VNIR In-Band Spectral Response Is Well Behaved

***Data is from first of three lots that will be used to select flight filters***

**Representative Plots of VNIR Bands**

- 0

- 350

- 450

- 550

- 650

- 750

- 850

- 950

**Wavelength [nm]**

**Absolute Trans [%]**

- CA

- BLU

- GRE

- RED

- NIR

## Pan and SWIR Spectral Response Is Excellent

***Data is from first of three lots that will be used to select flight filters***

## Spectral Transmission Exceeds Requirements For All Wafers

**Average Transmission Between 50% Points**

**( Spec 3.2.6)**

- CA

- CA

- CA

- BLU

- BLU

- BLU

- GRE

- GRE

- GRE

- GRE

- GRE

- GRE

- RED

- RED

- RED

- RED

- NIR

- NIR

- PAN

- PAN

- PAN

**Band**

**Absolute Transmission [%]**

- Wafer

- Spec

**Spectral Transmission Exceeds Requirements For All Wafers**

***Greater than spec is good***

**Average Relative to Peak Response**

**(Spec 3.2.7.1  Spectral Flatness)**

- CA

- CA

- CA

- BLU

- BLU

- BLU

- GRE

- GRE

- GRE

- GRE

- GRE

- GRE

- RED

- RED

- RED

- RED

- NIR

- NIR

- PAN

- PAN

- PAN

**Band**

**Relative transmission [%]**

- Wafer

- Spec

## Spectral and Scatter Out-of-Band Response Meet EDU and Most Flight Requirements

**(Spec 3.2.9.1)**

**(Spec 3.2.10)**

***Less than spec is good***

- Initial results indicated we don’t have the “VIIRS filter problem.”

***CA spectral OBR being addressed in Lots 2 and 3***

**Preliminary Scatter OBR**

- CA

- CA

- CA

- BLU

- BLU

- BLU

- GRE

- GRE

- GRE

- GRE

- GRE

- GRE

- RED

- RED

- RED

- RED

- NIR

- NIR

- PAN

- PAN

- PAN

**Band**

**SOBR [%]**

- Wafer

- Reqmt

**Preliminary Spectral OBR**

- CA

- CA

- CA

- BLU

- BLU

- BLU

- GRE

- GRE

- GRE

- GRE

- GRE

- GRE

- RED

- RED

- RED

- RED

- NIR

- NIR

- PAN

- PAN

- PAN

**Band**

**OBR [%]**

- Wafer

- Reqmt

## Summary

## Summary

**OLI is on schedule**
**Requirements and Design are stable**
**Hardware’s starting to roll in**
**Preliminary data from focal planes and filters is all positive**