Timeline of LASP solar irradiance measurements over the prior and future decades. The SORCE mission launched in January of 2003 and was the first mission to contain a full solar irradiance suite, including a TSI instrument and several SSI instruments coving the X-rays through the near IR. Two new technology missions (CSIM-FD and CTIM-FD) overlapped with the TSIS-1 mission and provided direct comparison and validation of measurement performance. For the SSI, the CSIM-FD early mission and the TSIS-1 SIM observations overlapped during the time of the solar minimum conditions in late 2019 as shown by the lower plot of the sunspot number as a proxy for solar cycle activity for SC24 and the beginning of SC25.