Shedding Light on Large Space-Based Telescopes: Modeling Stray Light due to Primary Mirror Damage from Micrometeoroid Impacts

TL;DR

This paper models how micrometeoroid impacts on large space telescopes' primary mirrors cause stray light, potentially reducing the detection of Earth-like exoplanets by 30-60%, highlighting the need for mitigation strategies.

Contribution

It provides the first estimates of stray light effects from micrometeoroid damage on space telescopes and assesses their impact on exoplanet detection yields.

Findings

Stray light from micrometeoroid impacts can reduce science yield by up to 60%.

Uncertainties remain due to unknown impactor energies and crater size relationships.

Damage mitigation strategies are essential for future telescope designs.

Abstract

A large space-based telescope aimed at detecting and characterizing the atmospheres of Earth-like planets orbiting Sun-like stars will require unprecedented contrast and stability. However, damage to the primary mirror due to micrometeoroid impacts will provide a stochastic, time-dependent source of stray light in the coronagraph's field of view that could significantly lengthen exposure times and reduce the expected science yield. To better quantify the impact of stray light and inform the Habitable Worlds Observatory mission design process, we present estimates of stray light in different micrometeoroid damage scenarios for a broad range of targets, and use that to find the expected decrease in science yield (i.e., the expected number of detected exoEarth candidates). We find that stray light due to micrometeoroid damage may significantly reduce yield, by 30% -- 60% in some cases, but significant uncertainties remain due to the unknown maximum expected impactor energy, and the relationship between impact energy and expected crater size. Micrometeoroid damage therefore needs further exploration, as it has the potential to reduce scientific yield, and in turn drive the development of mitigation strategies, selection of telescope designs, and selection of observing priorities in the future.