Dataset for M. Simeoni et al., Smart and Flexible Optical Solar Reflectors for Passive Radiative Cooling Regulation in Space using W:VO2 Metasurface Dataset DOI: 10.5258/SOTON/D3707. Dataset consists of a single excel file with spreadsheet for each subfigure/figure with following formats Main manuscript Figure 1: Figure 1a: no associated data. Figure 1b: no associated data. Figure 1c: no associated data. Figure 2: Figure 2a: no associated data. Figure 2b: no associated data. Figure 2c: Sheet Fig 2c wavelength as Column 1, absorption spectra for Square 1.5, 2.3, 3.1, 3.9, 4.7 um and Film as Column 2 to Column 7, respectively. Figure 2d: Sheet Fig 2d wavelength as Column 1, absorption spectra for Square 1.5, 2.3, 3.1, 3.9, 4.7 um and Film as Column 2 to Column 7, respectively. Figure 2e: Sheet Fig 2e wavelength as Column 1, absorption spectra for Gap 1, 2, 3, 4 um and Film as Column 2 to Column 6, respectively. Figure 2f: Sheet Fig2f wavelength as Column 1, absorption spectra for Gap 1, 2, 3, 4 um and Film as Column 2 to Column 6, respectively. Figure 2g: Sheet Fig 2g hot emissivity values in 2D array, with various gap size and then film in Row 1 and Square in Column 1. Each matrix element represents the calculated hot emissivity value corresponding to its row and column. Figure 2h: Sheet Fig 2h cold emissivity values in 2D array, with various gap size and then film in Row 1 and Square in Column 1. Each matrix element represents the calculated cold emissivity value corresponding to its row and column. Figure 2i: Sheet Fig 2i delta emissivity values in 2D array, with various gap size and then film in Row 1 and Square in Column 1. Each matrix element represents the calculated delta emissivity value corresponding to its row and column. Figure 2j: Sheet Fig 2j hot absorption (alpha) values in 2D array, with various gap size and then film in Row 1 and Square in Column 1. Each matrix element represents the calculated hot absorption value corresponding to its row and column. Figure 2klmn: Sheet Fig 2klmn Coverage (Column 1) vs Epsilon hot (Column 2), Epsilon cold (Column 3), Delta epsilon (Column 4) and Alpha hot (Column 5). Figure 3: Figure 3a: no associated data. Figure 3b: no associated data. Figure 3c: Sheet Fig 3c LESR3 OSR Absorption (1-R) spectra (%) with wavelength (um) (Column 1) at Hot (Column 5) and Cold (Column 4). Normalized blackbody spectra at 300 K and 5777K as (Column 2) and (Column 3). Figure 3d: Sheet Fig 3d LESR4 OSR Absorption (1-R) spectra (%) with wavelength (um) (Column 1) at Hot (Column 5) and Cold (Column 4). Normalized blackbody spectra at 300 K and 5777K as (Column 2) and (Column 3). Figure 4: Figure 4a: no associated data. Figure 4b: no associated data. Figure 4c: no associated data. Figure 4d: Sheet Fig 4d absorption (1-R) spectra (%) (Column 2) with wavelength (um) (Column 1). Normalized blackbody spectra at 5777K as (Column 3). Figure 4e: Sheet Fig 4e absorption (1-R) spectra (%) at various temperatures (Column 2 - 19) with wavelength (um) (Column 1). Normalized blackbody spectra at 70C and 20C as (Column 23) and (Column 24), respectively, with wavelength as (Column 22). Figure 4f: Sheet Fig 4f Emissivity (Column 2) vs Temperature (Column 1). Supporting Information Figure S1: Sheet Fig S1, Raman intensity for sputtered VO2 (Column 2) vs Raman shift (Column 1) and Raman intensity for ALD VO2 (Column 4) vs Raman shift (Column 3). Figure S2: no associated data. Figure S3: no associated data. Figure S4: no associated data. Figure S5: Figure S5a: Sheet Figure S5a Absorption (1-R) spectra (%) at various temperatures at Columns (Row 1 as temperature header) with wavelength (um), Column 1. Figure S5c: Sheet Figure S5c Emissivity (Column 2) vs Temperature (Column 1). Figure S6: Figure S6a: Sheet Fig S6a hot emissivity values in 2D array, with various gap size in Row 1 and Square in Column 1. Each matrix element represents the calculated hot emissivity value corresponding to its row and column. Figure S6b: Sheet Fig S6b cold emissivity values in 2D array, with various gap size in Row 1 and Square in Column 1. Each matrix element represents the calculated cold emissivity value corresponding to its row and column. Figure S6c: Sheet Fig S6c delta emissivity values in 2D array, with various gap size in Row 1 and Square in Column 1. Each matrix element represents the calculated delta emissivity value corresponding to its row and column. Figure S6d: Sheet Fig S6d hot absorption (alpha) values in 2D array, with various gap size in Row 1 and Square in Column 1. Each matrix element represents the calculated hot absorption value corresponding to its row and column. Figure S7: no data available. Figure S8: no data available. Figure S9a: Sheet Fig S9a n (Column 2) and k (Column 3) for YF3 vs wavelength in um (Column 1). Figure S9b: Sheet Fig S9b n (Column 2) and k (Column 3) for ZnS vs wavelength in um (Column 1). Figure S10: no associated data. Figure S11: no associated data.