Top left panel: phase-folded RV measurements of K2-285 over the period of planet b, after eliminating the signal from planets c, d, and e, and the stellar activity signal. Top right panel: as in the top-left panel but for planet c. Middle left panel: as in the top-left panel but for planet d. Middle right panel: as in the top-left panel but for planet e. Bottom panel: as in the top-left panel but for the stellar activity signal. The derived semi-amplitudes for these planets are m s⁻¹, m s⁻¹, m s⁻¹ and m s⁻¹, while the stellar activity signal has an amplitude of m s⁻¹. This translates into a mass determination of M_⊕ and M_⊕ for planets b and c, respectively, and upper-limit mass determinations of 6.5 M_⊕ and 10.7 M_⊕ (at 99% confidence level) for planets d and e, respectively.