European Space Operations Center System Testing by Flight Operators the Rosetta Experience E. Montagnon, P. Ferri, L. O Rourke, A. Accomazzo, I. Tanco, J. Morales, M. Sweeney Spaceops 2004, Montréal, Canada, 17-21 May 2004 May 18, 2004
The Rosetta Mission Cornerstone mission of ESA scientific program Objective: orbit and land on a comet nucleus Originally due for launch in January 2003 to comet Wirtanen Launch delayed by one year due to Ariane 5 accident mid- December 2002 Mission redesigned to a new comet target Churyumov- Gerasimenko launch in February 2004 May 18, 2004; Page: 2
The Rosetta Mission Profile Launch in February 2004 with Ariane 5 Planetary Swing-bys to Earth (3) and Mars Rendezvous with comet Churyumov-Gerasimenko in 2014 Delivery of a Lander to the comet surface in November 2014 Main scientific mission at the comet until end of 2015 Date Event Sun Distanc e (AU) Earth Distanc e (AU) 26/02/04 Launch 1 0 Delta- V (m/s) Jun. 04 Deep Space Manoeuver 1 0.89 0.3 165 Dec. 04 Deep Space Manoeuver 2 1.08 0.5 0 03/03/05 Earth Swing-by 1 1 0 Oct. 06 Deep Space Manoeuver 3 1.0 1.9 39 26/02/07 Mars Swing-by 1.44 2.11 14/11/07 Earth Swing-by 2 1 0 Mar. 09 Deep Space Manoeuver 4 2.2 2.8 87 11/11/09 Earth Swing-by 3 1 0 14/05/11 Rendezvous Manoeuver 1 4.4 3.4 649 06/08/14 Rendezvous Manoeuver 2 3.6 2.7 673 May 18, 2004; Page: 3
7.0 Distance (AU) 6.0 5.0 4.0 3.0 2.0 1.0 0.0 01/2004 Launch 260204 07/2004 01/2005 Earth Distance Sun Distance Mars Flyby 270207 Earth Flyby 07/2005 01/2006 07/2006 01/2007 Earth Flyby 07/2007 01/2008 07/2008 01/2009 RVM 1 100511 Earth Flyby Asteroid Flyby 07/2009 01/2010 07/2010 01/2011 07/2011 01/2012 Comet Orbit Insertion 220814 07/2012 01/2013 Landing 101114 07/2013 01/2014 RVM 2 220514 07/2014 01/2015 07/2015 Date May 18, 2004; Page: 4
Rosetta AIV Approach Initial Structural Model later refurbished as Engineering Model (EQM) EQM Test campaign objective: validate the electrical interfaces / software before final test campaign on Proto-flight Model (PFM) Due to delays in hardware and software delivery, sequential EQM / PFM testing approach had to be abandoned and a new approach adopted in 2002: Hardware integration and testing performed on PFM with a frozen software version EQM used in parallel to validate on-board software and investigate Non- Conformances Validated on-board software installed on PFM shortly before launch campaign start PFM Software verification by a reduced set of system tests EQM was to be delivered to ESOC after January 2003 launch May 18, 2004; Page: 5
EQM Characteristics Full-scale Model Data Management Subsystem: fully representative with exception of PROMs replaced by EEPROM Attitude and Orbit Control Subsystem: at least one fully representative physical unit for all sensors and actuators Power Subsystem: solar arrays not mounted Thermal Subsystem: no thermal hardware Telecommunications Subsystem: one fully representative transponder out of 2, Antennas not mounted Payload: electronic box with operational SW for most of the instruments May 18, 2004; Page: 6
EQM Test Campaign in 2003 After launch postponement, EQM delivered to ESOC in March 2003 New on-board software (OBSW) was under development for uplink in flight in June 2003 OBSW delivered in May 2003 OBSW system testing and validation performed under Industry and ESOC joined responsibility using EQM Test schedule driven by deadline for burning new OBSW in PROM: mid-august 2003 May 18, 2004; Page: 7
Test Campaign Activities New On-board Software test campaign included following activities Non-conformances (NCR) re-testing and close-out Validation of new SW functions Mission sequence tests with new SW Activities split between Industry and ESOC based on following criteria NCR close-out remains under Industry responsibility Testing of new functions by ESOC Mission sequence tests split between Industry and ESOC based on availability or not of test sequences in Industry s checkout system May 18, 2004; Page: 8
ESOC Test Campaign Contents Major SW functions validation File Transfer (prior to initial launch) Mission Timeline (prior to initial launch) Back-up Mission Timeline Operational Context Saving Mission Sequence Tests Launch and Early Orbit Phase (Nominal and Contingency case) Asteroid Flyby Near Sun Hibernation Entry / Exit Deep Space Hibernation Entry / Exit Back-up Modes Tests (Safe and Survival Mode) Long Duration Test: Commissioning simulation over 5 continuous days with Payload operations in realtime and off-line May 18, 2004; Page: 9
Test Characteristics Use of flight timeline and procedures Use of operational Flight Dynamics products Simulation of ground station passes Use of on-board Mission Timeline Use of mission control operational tools Simulation of signal travel time Payload Operations May 18, 2004; Page: 10
Spacecraft Test Configuration Test equipment (SCOE) used only for power-on and dynamics simulation start Remaining configuration and operations carried out from the Rosetta Control Room using the flight Mission Control System Avionics Configuration as for flight Mass memory set-up with all files required for flight Telemetry storage enabled, Flight Telemetry Modes, Mission Timeline started AOCMS in close loop with Flight Dynamics simulation as per simulated mission phase All SW tables and defaults configured as per simulated mission phase May 18, 2004; Page: 11
EQM Operations Set-up Power SCOE EQM AOCS SCOE Checkout System TM/TC Front End Industry Test Equipment NDIU RSDB To/From PFM NCTRS Mission Control System Flight Equipment NDIU: Network Data Interface Unit ground station simulator; NCTRS: TM/TC Router; RSDB: Rosetta System Database May 18, 2004; Page: 12
Tools Commonality Network Data Interface Unit presents the same interface as the ESA Ground Station, thus allowing usage of flight equipment for ground testing. Joined testing by Industry and ESOC possible thanks to common database used throughout the Rosetta Project for Software Generation, AIV and Operations Different control systems used for AIV and Operations Major drawback: systems had conflicting requirements on database structure May 18, 2004; Page: 13
Test Results About 6 weeks of OBSW testing by Flight Operators 30 non-conformances raised, from which 22 on spacecraft subsystems All on-board software non-conformances fixed in time for PROM burning Consolidation of the flight timelines and procedures Problems detected on the Mission Control System Best training ever for the Flight Control Team May 18, 2004; Page: 14
EQM Activities at ESOC After completion of OBSW test campaign, EQM used to investigate Non-Conformances and validate SW patches before uplink to the PFM Long Duration Test repeated in December 2003 to validate problem fixes on the Mission Control System EQM used in December 2003-January 2004 for payload commissioning simulations as part of the Rosetta Simulations Campaign New OBSW version under development for Uplink in flight in June 2004 system testing and validation to be carried out by ESOC under overall responsibility from Industry May 18, 2004; Page: 15
Recommendations A hardware representative test bench to be provided to the flight operators, especially for long-duration missions Main advantage w.r.t. traditional SW-based simulator in area of Avionics interface to other units and Payloads Such test bench not to be used instead of but rather in parallel to the traditional SW -based simulator Contingency cases can not be as easily trained on HW test bench. Spacecraft AIV programs to include a slot for system testing by operators in addition to the traditional test slot dedicated to database validation It is less effort for operators than for industry to design and carry out realistic test scenarios thanks to the availability of flight tools, documentation and expertise. May 18, 2004; Page: 16
Conclusion Smooth integration of EQM in Rosetta ground segment thanks to tools commonality between AIV and Operations System test activities prepared and performed very efficiently by Rosetta operators thanks to the use of flight equipment and procedures Unique experience gained by operators thanks to EQM-PFM similarities Use of real hardware on EQM Development of realistic test cases based on Flight Timelines and Procedures Rosetta EQM still heavily used by ESOC and Industry to analyze nonconformances and validate procedures / software Experience of Rosetta EQM integrated AIV / Operations system testing used to define approach for future long-duration missions May 18, 2004; Page: 17