Integrating sustainability into early systems engineering for the Habitable Worlds Observatory

The Habitable Worlds Observatory (HWO) aspires to answer a broad range of key questions in astronomy, including whether life exists beyond Earth. In the global sustainability context of the 2030s and 2040s, the credibility and impact of a space mission will also depend on demonstrating responsibility to the only habitable world we know. We present a framework to integrate the environmental dimension of sustainability into early HWO development by tracking the carbon footprint of mission activities and treating a carbon budget as a formal engineering constraint, integrated with traditional budgets (e.g. mass, power, and cost) through their natural systems-level interdependencies. This work identifies actionable practices, pathways to encourage stakeholders and partners, and lessons from other large-scale scientific enterprises. Our approach will position HWO as a technical, scientific, and ethical example: advancing space astronomy and meaningfully contributing to a sustainable future.