# COSMIC-2 Mission Summary at Three Years in Orbit
## 2 Mission Status and Milestones
### Program Milestones  
Since launch and instrument activation the program team worked extensively to check-out spacecraft and payload health, verify performance, and make initial configuration and software adjustments. Following this, on-orbit neutral atmosphere and ionosphere calibration/validation activities commenced and progressed, resulting in operational/validated product releases as individual milestones were reached. To date, there have been two and five neutral atmosphere and ionosphere data releases, respectively, and several important program milestones have been reached, as summarized in Table 3.  
The team supporting calibration and validation of TGRS neutral atmosphere products consists of experts from The Aerospace Corporation (Aerospace), CWB, JPL, Joint Center for Satellite Data Assimilation, National Central University, NOAA, NSPO, and UCAR (neutral atmosphere cal/val lead). Metrics evaluated include RO profile counts and distribution, bending angle noise metrics, bending angle/refractivity/temperature comparison to global numerical weather prediction (NWP) forecasts/analyses, evaluation of 1D-var retrieval products, inter-comparisons with other RO missions (e.g., KOMPSAT-5, MetOp, PAZ) and radiosondes, NWP assimilation system observation-background statistics, and NWP impact studies [1; 5; 6; 11]. Provisional neutral atmosphere products were released in December 2019, following initial validation of the retrieved products. The neutral atmosphere Initial Operational Capability (IOC) was achieved in February 2020, based on: stable and routine processing in place at both DPCs; early orbit inter-satellite product comparisons showed precision metrics meeting requirements; products compared against global NWP solutions, other RO missions, and radiosondes, and shown to meet requirements; verification that GPS and GLONASS profiles yielded consistent results, or differences understood; issues encountered were documented, and open issues tracked with plans to close them defined. Following a successful review, validated products were released in March 2020. Neutral atmosphere FOC was achieved in March 2021, following verification of product quality, level 1 science requirements, and operations performance after all satellites reached the final orbit configuration. The team supporting calibration and validation of ionosphere products consists of experts from Aerospace (ionosphere cal/val lead), CWB, JPL, National Cheng Kung University, NCU, NOAA, NSPO, UCAR, University of Texas at Dallas. Electron density profiles and relative TEC were initially verified and released. GPS and GLONASS absolute TEC were validated and released in 2020 and 2021, respectively [23; 24]. IVM density data were released in March 2021 [25]. Most recently, in March 2022, IVM temperature and composition validated by comparing to Jicamarca Radio Observatory measurements, and early \begin{table}
\begin{tabular}{c c c} \hline \hline
**Milestone** & **Date** & **Comments** \\ \hline First payload activation & 16-07-2019 & Checkout begins \\ Satellite IOC & 22-10-2019 & Formal program review \\ Neutral atmosphere data release 1 & 10-12-2019 & Provisional TGRS products \\ Neutral atmosphere IOC & 24-02-2020 & Formal program review \\ Neutral atmosphere data release 2 & 06-03-2020 & Validated TGRS products \\ Ionosphere data release 1 & 30-03-2020 & Provisional TGRS relative TEC, \\ Ionosphere data release 2 & 18-09-2020 & onboard S4, electron density profiles \\ Ionosphere IOC & 19-11-2020 & Formal program review \\ Ionosphere data release 3 & 29-01-2021 & TGRS GLONASS absolute TEC \\ Ionosphere data release 4 & 29-03-2021 & IVM ion density \\ Neutral atmosphere FOC & 31-03-2021 & Formal program review \\ Mission FOC & 15-09-2021 & Formal program review \\ Ionosphere data release 5 & 16-03-2022 & High rate observation scintillation \\  & & indices, early orbit IVM ion \\  & & temperature, composition, and drift \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Major post-launch program milestones. mission FM1 drifts were released.