> **LANDSAT DATA CONTINUITY MISSION**
>
> **OPERATIONAL LAND IMAGER**

**(OLI)**

> **SPECIAL**
>
> **TEST REQUIREMENTS**
>
> **May 13, 2005**

![](media/image1.png)

**[Signature Page]{.underline}**

+----------------------------------+-----------------------------------+
| ***Prepared by:***               |                                   |
+----------------------------------+-----------------------------------+
| \_\_\_\_\_\_\_                   |                                   |
|                                  |                                   |
| Brian Markham Date               |                                   |
|                                  |                                   |
| Cal/Val Manager                  |                                   |
|                                  |                                   |
| NASA/GSFC --Code 614.4           |                                   |
+----------------------------------+-----------------------------------+
| ***Reviewed by:***               |                                   |
+----------------------------------+-----------------------------------+
| \_\_\_\_\_\_\_                   |                                   |
|                                  |                                   |
| Jeanine Murphy-Morris Date       |                                   |
|                                  |                                   |
| OLI Instrument Manager           |                                   |
|                                  |                                   |
| NASA/GSFC -- Code 427            |                                   |
+----------------------------------+-----------------------------------+
| ***Approved by:***               |                                   |
+----------------------------------+-----------------------------------+
| \_\_\_\_\_\_\_\_                 |                                   |
|                                  |                                   |
| William Ochs Date Date           |                                   |
|                                  |                                   |
| LDCM Project Manager             |                                   |
|                                  |                                   |
| NASA/GSFC -- Code 427            |                                   |
+----------------------------------+-----------------------------------+

![](media/image2.pct){width="1.0416666666666666e-2in"
height="1.0416666666666666e-2in"}**LDCM PROJECT**

**DOCUMENT CHANGE RECORD**

Sheet: 1 of 1

+-----------+----------------------------------------------+-----------+
| **REV**   | **DESCRIPTION OF CHANGE**                    | **DATE**  |
|           |                                              |           |
| **LEVEL** |                                              | **A       |
|           |                                              | PPROVED** |
+-----------+----------------------------------------------+-----------+
|           |                                              |           |
+-----------+----------------------------------------------+-----------+

# 1.0 Introduction 

The LDCM program elements are dependent on the preflight
characterization and calibration of the instrument, and in particular on
the data sets and written reports from those tests. It is through the
preflight test reports that the required elements of the instrument
Image Assessment System will be identified. In addition, the algorithms
to produce the L1R and L1G image products will be developed using these
preflight data sets.

The purpose of the pre-flight and post-flight test requirements is to:

-   verify that the instrument's operation conforms to specifications;

-   establish the instrument's as-built performance;

-   test for abnormalities in the sensor's response;

-   provide an at-launch estimate of the sensor\'s radiometric
    calibration;

-   provide calibration data sets that are otherwise unobtainable in
    flight or on the ground (such as spectral band characteristics, PSF
    parameters, solar diffuser calibration); and

-   determine the instrument's radiometric stability.

The following descriptions of test requirements serves as a template for
the minimum set of tests that must be included in the calibration
validation test plan as part of the Contract Data Requirements List
(CDRL) and of the overall assurance program.

The OLI Instrument contractor has the responsibility for providing an
NPOESS compatible instrument capable of providing well calibrated and
well characterized specification compliant data, to ensure Landsat data
continuity. The Government has the responsibility for independently
assuring that the delivered instrument will be specification compliant
on the NPOESS platform and sufficiently well calibrated and
characterized to fulfill the Mission objectives. The following Special
Test Requirements (STRs) are an essential component of that assurance
program. The results of the tests shall be reported as part of the
program's set of Contract Data Requirements Lists (CDRLs).

2.0 During the pre launch phase the contractor shall, at a minimum:

1.  a\) Characterize the relative spectral radiance response for each
    band of the instrument and the variation of this response within the
    band.

i\. The in-band (between 1% response points) relative spectral radiance
response shall be measured at the integrated instrument level under
simulated on-orbit operating conditions (vacuum and focal plane
temperatures). If only a representative sample of detectors are tested,
then this sample shall include at least 10% of the detectors in each
band uniformly distributed across the focal plane, i.e., samples from
center and edges of each sensor chip assembly.

ii\. The Out-of-Band relative spectral radiance response of the
instrument shall be determined down to a sensitivity of 5 orders of
magnitude (below the peak in-band value) across the wavelength range of
the sensitivity of the detectors used in the particular band. This
determination shall be based on measurements of the mirrors as well as
measurements made after detectors are mated to filters or at higher
levels of assembly. The detector/filter measurements shall be made under
operational temperature and angular conditions with adjacent bands
illuminated. The integrated out of band response shall be determined
using the solar exoatmospheric curve in section 4.2.4.2.3 of the
instrument specification as a weighting function.

1.  b\) Characterize the stability of the spectral transmission of the
    spectral band bandpass filters between ambient and vacuum conditions
    at their expected operating temperature and angular conditions.
    Witness filters shall be measured in ambient and daily over at least
    7 days of continuous vacuum exposure.

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1.  c\) Characterize the spatial edge response based on measurements at
    the integrated instrument level under simulated on-orbit operating
    conditions (vacuum and temperatures) for a representative sample,
    i.e., 11 field angles (Scale Factors of Field of View (FOV): -1,
    -.89, -.77, -.63, -.44, 0, .44, .63, .77, .89, 1.0) across the
    entire FOV in all bands. Examine edge spread response data for
    possible crosstalk between spectral bands on the same focal plane.

    d\) Characterize the stray light rejection and internal light
    scattering of the instrument based on measurements at the component
    level or above and analysis. The stray light model shall be
    developed using a generally-accepted non-sequential ray trace
    method, e.g. ASAP, APART, GUERAP, Trace Pro. The stray light model
    shall encompass the spacecraft and other spacecraft instruments and
    the entire optical system, including baffles and the focal plane,
    detectors and mounting devices. Include a stray light analysis of
    the solar diffuser panel(s) in the deployed position. This analysis
    shall include glints and shadowing on the diffuser by the spacecraft
    and other spacecraft instruments as well as the instrument itself.
    As part of this analysis, demonstrate that diffuser measurements on
    orbit are not contaminated by reflected light from the earth and the
    atmosphere. Collect data at the integrated instrument level
    sufficient to look for instrument stray light effects not predicted
    by the stray light model. Characterize the throughput of any
    diffuser stray light baffling system. Characterize all applicable
    spectral bands to allow for possible improvements to the instrument
    stray light model. Included within this general stray light
    characterization and analysis special test requirement are
    measurements and analysis to confirm a more specific type of stray
    light, which is addressed in the ghosting system specification
    requirements. In tests at the integrated instrument level associated
    with this requirement verification the minimum size object diameter
    for testing will be equivalent to the larger of an enclosing
    diameter of 1/10 of the FPA across-track FOV or twice the SCA
    extent.

    e\) Radiometrically calibrate all detectors at the integrated
    instrument level in absolute units with NIST traceability under
    simulated on-orbit operating conditions (vacuum and focal plane
    temperature). Characterize the calibration across the expected
    instrument operating temperature range. Collect sufficient
    calibration data sets and characterization data to demonstrate that
    the calibrated data will meet the absolute radiometric accuracy,
    radiometric signal to noise, and radiometric stability requirements
    on orbit.

    f\) Determine the mathematical equation(s) to convert the instrument
    output in DN to input radiance in W/m\^2-sr-um. Demonstrate the
    validity of the equation(s) with integrated instrument level
    measurements for a sampling of detectors.

    g\) Characterize the on-board solar calibrator for on-orbit use.
    This shall include characterization of the bidirectional reflectance
    of the solar diffuser panel across the range of solar incidence
    angles and focal plane view angles to be used on orbit.  In
    addition, characterize the angular throughput of any diffuser view
    limiting devices across the range of angles to be used on orbit. 
    Conduct an integrated instrument level characterization of the
    radiometric throughput of the solar calibrator across a subset of
    the angles to be used on orbit.

    h\) Characterize additional on-board calibration devices for
    on-orbit use. This shall include characterization of the stability
    of the internal calibration lamp system. Provide an integrated
    instrument level observation of at least one device that is expected
    to be radiometrically stable through launch. This observation shall
    be repeatable on orbit to assess the transfer of the pre-launch
    radiometric calibration to on-orbit calibration (i.e., Transfer to
    Orbit Measurement).

    i\) Characterize the Signal to Noise Ratio (SNR) of all detectors
    for integrated instrument level measurements under simulated
    on-orbit operating conditions (across the on-orbit sensor
    temperature range and in vacuum) and across the dynamic range of the
    sensor.

    i.1) For each SCA characterize the bias and dark level relationship
    between all imaging and dark reference detectors for integrated
    instrument level measurements under simulated on-orbit operating
    conditions (across the on-orbit sensor temperature range and in
    vacuum).

    j\) Characterize the coherent noise of the instrument with
    spacecraft level measurements under simulated on-orbit operating
    conditions including contributions from the spacecraft (across
    temperature range and in vacuum).

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1.  k\) Characterize the linear polarization sensitivity of the
    instrument by component level measurements and analysis. Measure the
    linear polarization sensitivity of a sampling of detectors (center
    and edges of field of view) at the integrated instrument level.

    l\) Characterize the bright target recovery and pixel-to-pixel
    electrical crosstalk of the instrument by focal plane level or above
    level measurements.

    m\) Collect data at the integrated instrument level sufficient to
    look for image artifacts such as pattern noise, striping, etc.
    Characterize any observed image artifacts to allow for possible
    improvements to the imagery.

    n\) Characterize the instrument's lines-of-sight (LOS) via
    measurements of all detectors LOS relative to the instrument
    coordinate system.

    o\) Demonstrate the relative stability of the detector lines of
    sight by measuring the relative locations of a selected set of
    detectors from each band and each SCA over the expected range of
    operating temperatures, to an accuracy ≤ 1 μrad (1-sigma) (TBR). The
    selected set of detectors shall include, at a minimum, the first,
    middle, and last even detector, and the first, middle, and last odd
    detector from each band on each SCA.

    p\) Measure the alignment of the instrument optical axes relative to
    the instrument alignment reference cube.

    q\) Demonstrate the instrument's band-to-band internal geometry
    stability over the expected range of operating temperatures.

    r\) Characterize the response, as a function of vibration frequency,
    of any jitter and/or attitude sensing devices provided with the
    instrument.

    s\) Characterize the alignment relative to the instrument optical
    axes of any jitter and/or attitude sensing devices provided with the
    instrument.

    t\) Measure the alignment of instrument optical axes relative to the
    instrument mounting interface over the full operating range of any
    pointing mechanisms in the instrument

    u\) Characterize the alignment stability of the instrument optical
    axes relative to the instrument mounting interface over the full
    operating range of any pointing mechanisms in the instrument

    v\) Demonstrate the ability to accurately reconstruct and register
    images in the VNIR bands from data collected under conditions that
    simulate the on-orbit target motion. This demonstration may be
    performed in segments over the full FOV of the instrument. This
    demonstration shall also include, but not be limited to,
    post-environmental spacecraft-level ambient testing, using an
    external target, to validate performance.

    w\) Characterize the detector-sampling timing pattern via
    measurement of any detector-specific electronic delays, sample
    phasing (e.g., even/odd detector timing offsets), and frame rate
    (i.e., time between samples) for each detector.

> x\) Provide and maintain a list of FPA defects, which include dead,
> inoperable, and out-of-spec detectors for each band.

16. y\) Characterize 1/f noise parameters baseline by measuring long
    dark collects and dark pixel collects under simulated on-orbit
    operating conditions (across the on-orbit sensor temperature range
    and in vacuum). Test includes, at a minimum, 6 acquisitions spaced 5
    minutes apart or one long continuous data collect with a similar
    time span. This test shall be repeated on orbit.

2.1 During the Commissioning phase, i.e., prior to Initial Operational
Capability, the contractor shall, at a minimum:

1.  a\) Characterize on-board calibrator initial on-orbit performance
    and health by testing reference source lamps operation and the solar
    diffuser. The Transfer to Orbit Measurement shall be completed (See
    STR 2.1.g).

    b\) Update the Detector Operability Status list with newly
    identified dead, inoperable, and out-of-spec detectors for each band
    (twice during Commissioning.)

    c\) Characterize the bright target recovery and crosstalk of the
    instrument (once during Commissioning).

    d\) Characterize the relative detector response for detectors within
    a band (once during Commissioning) and update the calibration
    parameters to correct pixel-to-pixel non-uniformity as necessary.

    e\) Characterize the stability and absolute radiometric calibration
    of the spectral bands (once during Commissioning \[or more
    frequently depending on stability of instrument\]) and update the
    absolute calibration coefficients and uncertainties as required to
    meet performance specifications.

    f\) Characterize the noise of the instrument at dark (both coherent
    and total noise) and at multiple illuminated levels between dark and
    L(high) (twice during commissioning).

    g\) Characterize the Dark bias drifts, 1/f noise parameters, and FPA
    detector statistics over an orbit for at least three different dark
    data collection methods (i.e. Earth scene of cold sea at night, dark
    reference detectors, closed shutter) (twice during Commissioning).

    h\) Characterize the instrument to Attitude Determination System
    Reference Alignment. The characterization shall include the combined
    optical axes to instrument and instrument to attitude reference
    alignment, which is equivalent to the knowledge of the optical axes
    to star trackers alignment.

    i\) Characterize the band locations on the focal plane(s) relative
    to the pan band (twice during Commissioning).

    j\) Measure the relative locations of the individual SCAs on the
    focal plane (twice during Commissioning) to an accuracy ≤ 2 μrad
    (1-sigma).

    k\) Characterize any variations in detector responsivity over a
    minimum of 2 instrument out gassing cycles periods during
    commissioning.

    l\) Examine the stray light and ghosting of the instrument (twice
    during commissioning).

> 2.2 All radiance calibration sources and transfer radiometers used by
> the contractor prior to launch shall be calibrated to National
> Institute of Standards and Technology (NIST) standards for radiometric
> calibrations.