**Statement of Work**

**New Features and Technical Support for Integrated Optical Design
Analysis Software**

**1.0 Introduction**

MSFC has developed an integrated modeling software product for
performing systems analysis of large space telescope systems. The
Integrated Optical Design Analysis software (IODA) provides a modeling
environment that seamlessly fuses together thermomechanical models with
optical models. This capability allows the design team to quickly see
the impact of changes in system design or environmental boundary
conditions directly on system imaging performance. The current software
uses NASTRAN or ALGOR Finite element model format files to define the
model geometry and import the static and dynamic deflections that are
mapped into a Code V optical model. IODA couples the data from these two
analysis codes to perform detailed opto mechanical design analysis of
the optical system.

**2.0 Scope**

The IODA software is being used by the NASA MSFC Integrated Modeling
Team to support Advanced Mirror System Demonstration (AMSD) testing at
the center. Up to three test articles are to be tested under this
program. The government and industry members of the modeling team have
used various models and analysis tools to design these test articles.
The current release of IODA supports use of NASTRAN, ALGOR, and CODE V,
the primary tools being used by the integrated modeling team. However,
other tools are being used internally and by the industry teams building
the hardware. In particular, ANSYS finite element analysis and ZeMAX
optical analysis codes are being used to analyze some components.
Developing the ability of IODA to interface with these tools shall
enhance the coordination of modeling efforts.

The AMSD mirrors shall use active force or displacement actuators to
improve the figure of the light weight mirrors. The ability of IODA to
address the effect of the actuators on the mirrors is currently limited
to manually changing the FEM model constraints to emulate an actuator
and analyzing the result. Modifications to the software are desired to
develop, within IODA, the ability to generate actuator influence
functions and export them for use in an external control algorithm.
Furthermore, IODA algorithms are desired that shall use the influence
functions to solve for optimum actuator positions for minimizing errors
in the mirror figure.

**3.0 Contractor Tasks**

The contractor shall work closely with the MSFC integrated modeling team
involved in this activity. The contractor activities shall involve
software development of features needed to improve the Integrated
Optical Design Analysis (IODA) software. The contractor shall perform
the following tasks:

1.  **Development of ANSYS Interface**

> The contractor shall develop the software algorithms needed to import
> ANSYS finite element models into the IODA modeling environment. The
> algorithms shall allow the user to; import an ANSYS model, use IODA to
> define optical surface nodes, generate Zernike and/or uniform grid
> representations of the deformed surfaces, map the surfaces to an
> optics model, and run optical analysis using the results. The ANSYS
> interface shall be developed to the same level as the existing NASTRAN
> interface to make the IODA software equally compatible with this
> alternative analysis tool.

**3.2 Development of ZeMAX Interface**

The contractor shall develop software algorithms to interface IODA with
the ZeMAX optical design code. This task will involve the development
algorithms specifically designed to generate ZeMAX compatible surface
error definition files using IODA to reduce the thermomechanical model
results and create a ZeMAX compatible input. The contractor shall work
directly with the ZeMAX vendor to develop the best approach for
integrating the IODA generated input files into the ZeMAX modeling
environment.

3.  **Active Mirror Actuator Positioning Optimization Algorithm**

> The contractor shall develop new features in the IODA software to
> support modeling of actively figured mirrors such as the lightweight
> primary mirrors being developed for the Advanced Mirror System
> Demonstrator. At a minimum the software shall include the following
> features:

-   The ability to use IODA to select and designate a set of single
    nodes as actuator control points.

-   The ability to specify key characteristics of the actuators such as
    minimum step size, maximum travel limits, and the direction of
    actuation (a fixed parameter).

-   The ability to generate NASTRAN single point constraint cards to
    simulate an enforced displacement caused by actuator displacements.

-   The ability to create a linear influence coefficient matrix defining
    the response of each node in the model to a unit activation of a
    displacement actuator. (Note rigid body motions tip, tilt, and
    piston will be excluded thus the model must include appropriate
    constraints to prevent rigid body motions).

-   A least squares fit algorithm using the actuator influence functions
    to solve for actuator positions that minimize the RMS figure error
    of the mirror surface.

**3.4 Support of Arbitrary Model Orientation in the IODA Environment**

IODA currently has the ability to address the problem that occurs when
the thermomechanical model and the optics model have been defined in
different coordinate systems. However, this feature is currently limited
to cases in which the thermo mechanical model has one of its principal
coordinate axes coincident with the direction of incoming light. There
could be cases were this orientation is not convenient for structural
analysis. Therefore, the contractor shall develop algorithms that
support arbitrary orientation of the structural model with respect to
the direction of incoming light.

**3.5 Integrated Optical Design Analysis (IODA) Technical Support**

The contractor shall provide technical support for the IODA software.
Support shall be provided on-site and shall include scheduled briefings
to update the modeling team on new software features, as they are
developed and also spontaneous support to address software problems and
issues that arise in the course of the normal modeling effort.

**4.0 Period of Performance**

The anticipated period of performance is 26 weeks.

**5.0 Deliverables**

The following are deliverable items to be provided by the contractor at
the conclusion of this effort:

-   A new release of the IODA software (including source code)
    incorporating the new features described above.

-   An updated IODA software Users Manual and demonstration models

-   A final report documenting the work performed.