System Testing by Flight Operators the Rosetta Experience

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System Testing by Flight Operators the Rosetta
Experience
European Space Operations Center

• E. Montagnon, P. Ferri, L. ORourke, A.
  Accomazzo, I. Tanco,
• J. Morales, M. Sweeney
• Spaceops 2004, Montréal, Canada, 17-21 May 2004

ESOC (TOS-OPR)
May 18, 2004
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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

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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

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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

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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

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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

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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 Industrys checkout system

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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
  real-time and off-line

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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

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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

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EQM Operations Set-up
To/From PFM
Power SCOE
AOCS SCOE
TM/TC Front End
NDIU
NCTRS
Mission Control System
Checkout System
NDIU Network Data Interface Unit ground
station simulator NCTRS TM/TC Router RSDB
Rosetta System Database
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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

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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

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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

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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.

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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 non-conformances and validate
  procedures / software
• Experience of Rosetta EQM integrated AIV /
  Operations system testing used to define approach
  for future long-duration missions