The main challenge is that the existing constellation of NOAA polar-orbiting satellites currently supporting Argos (NOAA-15, 18, and 19) is severely aging and is operating past its design life. If all the satellites are decommissioned as planned and the satellite launches fall through, all Argos satellite coverage will cease as of 2027. As of 2022, Argos satellite coverage is still limited to early morning and mid-morning.
In June 2015, NOAA pledged to launch one of several new Argos-4 instruments in 2019, contingent upon the availability of funds. The NOAA program facilitating the launch is called Cooperative Data and Rescue Services (CDARS). That launch has since been delayed until 2022.
President Trump’s FY 2018 budget request included a five-year funding timeline that delays CDARS and the launch of new Argos equipment until 2022.