Illustrates the balancing act of keeping thermal noise minimal while maximizing the detectability of spectral features like CO₂ and CO. The top plot shows the relative noise based on varying telescope temperature between 0.8 and 2.0 μm. The bottom plot shows spectral features from 0.8 to 2.0 μm of H₂O, CH₄, O₂, CO, and CO₂. We plot a modern-Earth spectra using the Planetary Spectrum Generator (PSG) with four varying CO₂ abundances: Modern (4.2 × 10⁻⁴ VMR) in dark blue, Proterozoic-like (1 × 10⁻² VMR) in light pink, Archean-like (1 × 10⁻¹ VMR) in magenta, and Venus-like (9.6 × 10⁻¹ VMR) in purple. The figure plots wavelength (μm) on the x-axis and apparent albedo (I/F) on the y-axis.