I will discuss the development of a multi-stage magnetic cooling system at NASA's Goddard Space Flight Center. The device, based on adiabatic demagnetization refrigerators (ADRs), is designed to continuously cool detectors at 0.05 K and optics at 4 K with high thermodynamic efficiency. We made significant progress in developing the system, including the production and testing of a single-stage 10-K- to-4-K ADR, the assembly of a two-stage 10-K-to-4-K CADR, and the fabrication and assembly of a four-stage 4-K-to-0.05-K CADR. Despite challenges, including a lack of access to key personnel and lab resources due to sudden emergence of flight work early in the development and later due to COVID-19, we are now successfully testing the system and optimizing its performance. This technology is currently baselined in four different instruments for future spaceflight missions.