TPF-C Technology Plan - Exoplanet Exploration Program - NASA

Chapter 1
expected architecture downselect from either a TPF-C or TPF-I in 2006, before the decision was
made to proceed with both observatories.
With the recent decision to move forward first with TPF-C on a schedule consistent with launch
readiness in 2016, the nature of the technology efforts must be reconsidered. The ultimate goal of
the technology development program is an operational TPF-C flight observatory. The project
must accelerate and complete pre-Phase A technology development activity in approximately
two years to a level sufficient for NASA to approve entry into the formulation phase (Phase A/B)
in 2007 and into the implementation phase (Phase C/D) in the 2011 timeframe, with the eventual
goal of NASA approval for a 2016 launch.
Briefly, to complete pre-Phase A successfully, three major activities must be implemented in an
integrated manner: testbed demonstrations, mission models, and error budget allocations. A
development flow is established to retire each identified technical risk by end of formulation
through laboratory demonstrations, validated models, and iteration of the error budget allocations
based on technology achievements. The critical technologies and the feasibility of the mission
based on the current design combined with mission models and error budgets must be
demonstrated. As laid out in the NASA Code S Management Handbook, in order to complete
Phase A, all technologies must be demonstrated to TRL 5, defined as “component and/or
breadboard validation in a relevant environment (ground or space),” and the engineering must be
within reach. The TRL levels attempt to standardize the description of technology maturity and
are discussed in more detail in Appendix E. To complete Phase B and enter implementation, all
technologies must be at TRL 6, defined as “system/subsystem model or prototype demonstration
in a relevant environment,” and a preliminary design must be shown analytically with validated
models to achieve the flight performance necessary to realize the mission science objectives.
The testbeds and models, with the error budget assumptions, developed during the formulation
phase of the Project must achieve the stated maturity, but must also be conceived with an eye for
their eventual programmatic purpose in the flight system test and verification activities and
investigation of potential anomalies during operation.
Ideally, one tests a flight system end-to-end at flight levels in a flight environment. In the case of
TPF-C, it will not be feasible to test the full system in this way due to the physical scale of the
observatory and the difficulty of creating an environment that sufficiently approximates flight for
the complete system. Confidence that the system will perform as expected on orbit will be
developed through validated models of the system. Verification of TPF-C flight hardware will be
accomplished via subsystem and component testing at the highest level to which these entities
can be confidently tested. The TPF-C technology development program will validate the physics
and scalability of these models at flight levels in flight environments. These models will then be
linked together to estimate the performance of TPF-C. The fidelity of the models in the highprecision
(picometer and milli-Kelvin) regimes and the model interfaces must have bounded and
verified performance as well. Recognizing that our models will never be fully complete, the
project will continuously review the mission models for omissions or errors based on testbed
performance results. In some cases, the most stringent requirements on testbed performance will
be levied by their role in model validation as opposed to technology demonstration. While it will
not be necessary to improve on flight performance levels in order to validate the models, it will
be necessary to design the testbed in such a way that it can be modeled accurately and the
components can be characterized and exercised to determine sensitivities. The remaining
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