Flux of a cloudy Venus-twin exoplanet (opaque H₂SO₄ clouds; dashed green line) compared to an icy world with a thin CO₂-dominated atmosphere (solid brown line). In the top panel, we plot the UV/O/NIR wavelength range. The hatched area represents the expected wavelength-dependent S /N = 10 noise for the LUVOIR A mission concept (The LUVOIR Team 2019). The thick, solid black line represents the expected S/N = 10 noise for the HabEx + Starshade mission concept (Gaudi et al. 2020). In the bottom panel, we plot the MIR wavelength range. The gray shaded region indicates the 1σ LIFESIM noise level at S/N = 10.