ENVISAT Spacecraft and Flight Operations Segment Status

1. ENVISAT Spacecraft and Flight Operations Segment Status Andreas Rudolph Mission Operations Department ESOC / ESA

2. Presentation Overview • Spacecraft and Instrument Operations Summary since the Calibration Review • Platform Status and Performances • Flight Operations Segment Status and Performance • Organisation at FOS and its Interfaces for Routine Phase • Conclusions

3. Spacecraft Operations Summary • First routine Out-of-plane manoeuvre for inclination correction performed in Sep-02 – combined with first attempt for activation of the P/L Module Computer software V38p1 • Leonid meteor storm protection operations carried out on 18 & 19-Nov – satellite & instrument brought to lower mode of operations as a precaution for the meteor storm • Successful uplink of the PMC Flight Software version 38 p1 (including a new list of patches) as part of Leonid ops. • V38p1 includes a proper memory scrubbing function and fixes to all major problems encountered since launch (PLSOL problems, etc).

4. P/L Module Availability

5. Instrument Operations Summary • The instrument operations since the calibration review went well overall • Several corrective patches have been applied successfully to • ASAR (e.g. TR parity switch-downs in Wave mode, product annotation error in Alternating Polarisation mode, …) • DORIS/MWR (ICU counter overflow) • SCIAMACHY (MCMD reception error, PMTC sign error) • The MIPAS sterling cooler vibration cancellation system has been disabled (without any significant performance degradation) to prevent unnecessary transitions to Refuse mode

6. Instrument Operations Summary - contd • For ASAR the activation of the last background mode, Global Monitoring, in Nov-2002 is causing occasional Refuse mode entries (spurious TR parity error detection) – a corrective patch for this problem is under development • For MERIS a few of the recent radiometric calibrations of Diffuser 1 have been lost due to a known ICU timing problem – a workaround / corrective patch is under discussion • The instruments have provided a high operational availability since the cal review

7. Instrument Availability May – Nov-2002

8. Instrument Availability May – Nov-2002 – contd.

9. Satellite Operations Outlook • On 17-Dec-2002 the next Out-Of-Plane manoeuvre is required for inclination control – this will lead to a short unavailability of the payload for nominal operations • Commissioning of the Artemis Ka-band link is planned for Mar-2003 following injection of Artemis to the Geo-stationary orbit. The planning and testing of this last satellite commissioning activity is in progress.

10. Platform Status and Performance • The performance of the Service Module has been excellent with 100% availability • All units are configured to the A-chain and perform nominally • The cat bed heaters are kept on permanently (without any degradation observed) to keep Hydrazine temperatures above 2 deg C – see FCV heater mat failure reported during the cal review

11. Service Module Single Event Upsets

12. Power Subsystem Solar array output shows good performance The average battery DOD level is varying between 10% to 15% with the current instrument operations profile

13. Satellite Thermal Evolution - Batteries

14. Satellite Attitude Control • The pointing of the satellite is very stable as already reported during the cal review • The AOCS H/W (gyros, star trackers, reaction wheels and magnetorquers) used in Stellar Modes work very well

15. Satellite Orbit Control Manoeuvres • Orbit control manoeuvres for +/- 1 km ground track control will be required throughout the mission: • Out-Of-Plane Manoeuvres (OCMs) for inclination control: approx. 3-4 / year - approx. 5 m/sec of V = approx. 23 kg Hydrazine • Fine Control Manoeuvres (SFCMs) for altitude control: one every 3 weeks - approx. 4 cm/sec of V per SFCM = approx. 3.6 kg / year • Number of SFCM’s will decrease until 2005/2006 and then rise again (solar cycle) • Hydrazine consumption: • 37.2 out of 314 kg have been used to date • No thruster controlled attitude acquisition modes or safe mode entered since end of LEOP

16. Flight Dynamics System AOCS Cmd Checker On-board S/W Maintenance System S/C TM/TC Database TM/TC Archiving: SPEVAL & WWW SPEVAL Spacecraft Simulator Telemetry System Telecommand System TC Kiruna TM Raw TM FOS External Interfaces Mission Planning System Svalbard Raw TC External Server LEOP Network GroundStations Flight Operations Control Centre (FOCC) Flight Operations Segment Systems

17. Flight Operations Segment Performance • The FOS components continue to provide very high availability: • Systems critical for satellite control (Flight Control System, OBSM, I/F to ground stations) have shown a quasi-100% availability • Mission Planning System and its interfaces to PDS, ESTEC and AO Providers work satisfactorily • Ground station performance (FOS part) for third quarter: • ESA’s Kiruna station provided 99.9% availability • Svalbard (S-band) service provided 97.2% availability • Flight Control Procedures work ok – new procedures added when required in response to anomaly investigations and resolution

18. Flight Operations Segment Status • Implementation of operational improvements and additional requirements continue: • Automatic DORIS manoeuvre command generation by FOCC under development • Testing and validation of MPS for Artemis operations started • Implementation of improved time correlation algorithms completed • On-board S/W maintenance system and facilities have been used to develop and validate a total of 33 patches for many of the on-board processors • Both 15m prime and 13m back-up antenna in Kiruna commissioned

19. FOCC Time Correlation Algorithms & Results • Improved time correlation algorithms products available since 9-Oct-2002 • Uses TM received in Kiruna as main reference for correlation On-Board Time to UTC • Independent verification against DORIS Atomic Time performed automatically

20. Satellite Operations & FOS Organisation Shaded Boxes under FOS responsibility

21. Conclusions • The satellite and its instruments are performing well operationally and are ready for the routine phase • Commissioning of the Artemis/Envisat Ka-band interface in-orbit is planned to be performed in Mar-2003 • The Flight Operations Segment and the Flight Operations and Support Teams in Industry, ESTEC and ESOC are set-up for the routine phase – ready to continue!