Data driven investigations of the Coronagraph Instrument as a starlight suppression yardstick.
Laurent Pueyo / Space Telescope Science Institute, PII
Objectives:
We will work with the Roman Coronagraph Instrument project to maximize the return of the Coronagraph Instrument technology demonstration mission, and transfer knowledge to the Astro2020 recommended Habitable World Observatory (HWO). We will do so by carefully analyzing ground test data during the initial period of performance.
Background:
The Coronagraph Instrument is the only flight demonstrator of a suite of technologies that are critical to exo-earth detection and characterization with HWO. For instance, lessons learned from the Coronagraph Instrument ground testing will inform the experimental design of system level technology demonstrations that will occur under the purview of the Great Observatories Maturation Program (GOMAP). Successful Coronagraph Instrument operations during the technology demonstration phase will define the baseline exoplanet imaging observing sequence for HWO during formulation (Phase A). Because the Coronagraph Instrument is a class D instrument, with reduced assurance standards permitted, the Coronagraph Instrument I\&T data might not be as thoroughly scrutinized as was done for previous NASA flagships such as JWST. Our proposed CPP program will augment existing Coronagraph Instrument project resources to characterize performance and optimize the observations during the technology demonstration phase. We will also extrapolate the Coronagraph Instrument results to HWO.
Methods:
We propose to conduct a suite of data driven investigations based on the Coronagraph Instrument ground test measurements to inform HWO technology maturation and mission formulation plans, and maximize the return of the Coronagraph Instrument the technology demonstration. This will include:
• Evaluating raw contrast model uncertainties using ground tests data, and establishing best practices to set Model Uncertainty Factors (MUFs) for HWO error budgets.
• Quantifying the relationship between model uncertainties and WFS\&C convergence time and identifying the tall poles in the instrument’s configuration. These will be precious lessons learned to design GOMAP demonstrators and preliminary HWO architectures during mission formulation.
• Measuring the wavefront noise rejection function of the Coronagraph Instrument’s WFS\&C subsystems –either using the LOWFS or the science camera. We will then use these measurements as yardsticks to quantify how much ground GOMAP needs to cover in order to demonstrate HWO compatible wavefront stability.
• Developing a target list composed of a wide range of companions, from stellar binaries to self-luminous planets. We will build an empirical flight contrast ladder that will be essential to demonstrate the Coronagraph Instrument’s science capabilities during its commissioning and technology demonstration phases.
• Designing observing sequences for the Coronagraph Instrument’s technology demonstration phase that are as informative as possible for HWO.
Significance:
This work will help optimize the Coronagraph Instrument observations during the technology demonstration phase, which will in turn pave the way towards compelling Coronagraph Instrument observations later in the mission. Such successful observations will provide a unique opportunity to anchor HWO yield predictions with the Coronagraph Instrument data.