Better global neutral density specification and forecast through the assimilation of COSMIC-2 sTEC measurements

Neutral density measurements are difficult to make, limited in number and coverage and
suffer from large biases and uncertainties. This makes the option to improve neutral den-
sity specification using the plentiful ionospheric measurements, very attractive for satellite
collision avoidance applications. Better neutral density specification and forecast can re-
duce the uncertainty in satellite and debris positioning, lower satellite fuel consumption,
and help prevent the Kessler Syndrome. The main question we answer here using the
Thermosphere Ionosphere Data Assimilation (TIDA) model is as follows: Is it possible
to improve the global thermosphere neutral density model results by assimilating only
ionospheric measurements? To illustrate the case we assimilate only slant TEC (sTEC)
measurements from COSMIC-2 and show improvement in neutral density during an 8 day
period (January 31 - February 7, 2022) that includes the minor geomagnetic storm that
lead to the loss of 48 SpaceX satellites.