Future Mission Needs for Information Technology Launch Vehicles

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Future Mission Needs for Information
TechnologyLaunch Vehicles
European Space Information Technology in the
21st Century ESOC, 27 September 2000
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Information Technology on current expendable
launchers

• Modern expendable launchers rely on information
  technology for their entire mission
• Fully automated ground check-out of launch
  vehicle, launch table systems and payload status
• Fully automated mission driven by the flight
  programme
• Flight safety guaranteed by the Flight
  Termination System.

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Future Evolutions

• Further automation and integration of the
  expendable launcher functions.
• Introduction of reusable launchers with
• increased launch frequency
• improved safety and reliability
• real time health monitoring of launch vehicle
  status
• fault tolerant avionics
• failure detection and recovery for preservation
  of the vehicle integrity (mission abort).

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Future IT evolution on ELVs

• Improve ground check-out
• Reduce false alarms
• Introduce optical bus for mass saving

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Reusable Launch Vehicles (RLVs)

• It is considered that significant reductions in
  the access to space cost may be achieved by the
  introduction of reusable launch vehicles.
• ESA has studied many RLV concepts since the
  beginning of the eighties. In particular within
  the FESTIP programme (1994-2000) several reusable
  and semi-reusable launcher concepts were designed
  and compared versus a defined reference mission.
• In parallel the technologies required for the RLV
  have been identified and the related developments
  have been initiated.

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The FLTP Programme

• To continue the work initiated in FESTIP and to
  improve the
• related European technological level, ESA has
  initiated the
• Future Launchers Technologies Programme (FLTP),
• whose objectives are
• to confirm the interest of launcher reusability
• to identify, develop and validate the related
  technologies
• to progressively implement on-ground and
  in-flight experimentation and demonstrations,
  required to achieve a sufficient level of
  confidence prior to the vehicle development
• to provide, through the analysis of candidate
  vehicle concepts, elements in support of a
  development decision, which is expected to be
  required around 2007
• to coordinate and harmonize the activities on
  launcher reusability performed at national level
  and in other ESA programmes.

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IT requirements from FESTIP

• In the ESA programmes described above, priority
  has been assigned to those technologies which are
  specific to the RLV.
• Several enabling technologies rely on the
  extensive use of computers (e.g. health
  monitoring systems). Nevertheless the technology
  developments have been oriented mainly to input
  data generation (sensors, measurement system) and
  to the effect of the health monitoring data on
  launch vehicle operations (corrective actions,
  mission abort).
• Therefore no specific development in the field of
  information technology has been undertaken,
  although RLVs will make use of information
  technology during all phases of their life.
• The precise definition of the IT requirements,
  the identification of the hardware architecture
  and the elaboration of suitable software is
  currently on hold
• Why?

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Reasons for low priority to IT developments.

• 1) There is no specific technical requirement
  related to reusable
• launchers which is not expected to be
  satisfied at the start of a
• future development programme
• Performance (computing speed, memory, ...)
• The earliest date for starting the development
  of a future launcher is 2007.
• If computer performance continues its
  exponential growth, by that time
• performance will be more than adequate for the
  reusable launcher needs.
• Protection against space environment Technology
  developments in
• this area will be driven by commercial
  satellites (which stay in space for
• years reusable launchers will remain in orbit
  only for hours or days).
• Reliability, fault protection Technology
  developments in this area will be
• driven by manned space programs for which safety
  is mandatory.
• 2) RLVs will be marginal users (few vehicles) of
  these technologies
• and cannot expect to drive their evolution.
  The budgets available for
• launcher-specific technologies are much
  smaller than those invested by the

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RLVs versus ELVs

• The expected economic advantage of the RLV
  compared to ELV is
• essentially based on the assumption of being able
  to sustain
• multiple missions with limited maintenance and
  operation cycle
• costs.
• To achieve that several improvements are required
  respect to traditional ELVs.
• In particular
• the design of the system must take into account
  the need for checking the status of each
  subsystem and for maintaining it
• the life cycle cost must be minimised rather the
  cost per mission
• the launcher components must be continuously
  checked and replaced just before failure.
• A highly automated Ground Support Equipment as
  well as a robust Health Monitoring System are
  required for the RLV.

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Specific needs of the RLV
Safety The ELV flight safety is ensured by the
Flight Termination System (FTS). For the RLV
critical mission phases such as abort and
atmospheric re-entry phases cannot rely on the
FTS to ensure the ground safety. Fault Tolerance
must be intrinsically implemented in the software
as well as at system and subsystems
level. Reliability The ELV reliability is
defined on the basis of a single mission (roughly
one hour). For Ariane 5 the reliability target
figure is 1410-3 and the avionics reliability
figure is in the order of 10-4 per mission. The
RLV will have to perform several missions (FLTP
requirement 100 missions), all with an increased
level of reliability (10-3) . A new approach
allowing failure detection and recovery for
vehicle preservation will have to be implemented.

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Characteristics of IT for RLV

• Health Monitoring Systems and Data Handling
  Systems able to process large volumes of data as
  well as real time information will be required.
• The RLV bit stream will not compatible with the
  current telemetry capabilities mass memory
  storage and/or use of data relay satellite will
  have to be considered.
• The required performance for vehicle guidance,
  navigation and control will depend strictly on
• the aerodynamic characteristics,
• the mission phases (abort sequences and re-entry
  phase) and
• the defined level of vehicle autonomy.
• Therefore the flight control system will make use
  of advanced sensors, high rate (optical) buses,
  high performance computers, advanced algorithms
  for autonomous guidance and navigation (including
  possibility of re-computing the optimal
  trajectory) and suitably sized actuators.
• .

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Health Monitoring System
An efficient HMS will require the ability to
handle large amounts of data and to recognise
patterns even in real time environment. The HMS
communicates with intelligent sensors within the
different vehicle systems A new philosophy for
signal acquisition, signal conditioning, data
conversion, data compression, data storage with
respect to ELVs will need to be implemented. The
Health Monitoring System (HMS) will be an
essential tool to identify - real time status
of vehicle components critical for flight.
This will allow to initiate corrective actions or
abort phases. - the vehicle components
requiring maintenance after a mission. This
will reduce the required maintenance and checks
between missions, thereby reducing the
launch costs..
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Engine Health Monitoring

• Key prerequisite to ensure vehicle reusability
• Main requirements
• - high engine reliability for mission success
• - allow rescue of vehicle in case of aborted
  missions
• - guarantee vehicle availability through fast
  turn around
• Main engine design impacts
• - engine control
• - failsafe engine design
• - on-board intelligence
• - quick inspection design
• - quick maintenance design

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Engine Health Monitoring objectives

• In-flight, real-time engine status assessment
• - detect potentially dangerous conditions
• - provide corrective actions to limit damage to
  engine components or to prevent engine
  failure
• Rapid engine health post-flight evaluation
• - collect in-flight measurements, store them on
  on- board computer, analyse data on-ground by
  a suitable health monitoring software
• - validate measurements, correlate data, provide
  engine diagnostics
• go/no-go need for special inspections
• estimate remaining engine life

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Engine Health Monitoring technologies

• Specific software development
• identification of suitable methodological
  approaches and development of associated software
  packages for
• measurement definition and validation,
• elaboration of indicators, data treatment,
• detection of anomalies and diagnostics
• development of damage counters methodologies for
  engine life estimation
• Sensor technologies
• development of new, semi- or non-intrusive
  sensors
• use of optical fiber networks
• application of optical fiber signal multiplexing

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FLTP Engine Health Monitoring Activities
HM Approaches and Software Development

• Neural Networks
• Kalman Filtering
• Functional Models
• Vibration Spectra
• Expert Systems ?
• Damage Counters
• (based on large amount of 3D FEM
  computations)
• Validation of methodologies on Vulcain test
• data base