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Mission Support Operations Contract
Telemetry ConfigurationControl Protocol
Mike Petkevich, [email protected]
Dr. Norman Kluksdahl, [email protected]
Eric LeBlanc, [email protected]
Elsa Sanchez De Hernandes, [email protected]
IETF-71, DTN WG, Philadelphia,
March 13, 2008
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Mission Support Operations ContractConstellation requirements:
NASA MOD and the LM MSOC contract are tasked to define, build and operate NASA’s Constellation Program Control Center. Complete requirements are published at:
http://www.everyspec.com/NASA/NASA+-+CxP+PUBS/
The fundamental requirement is:• Tolerate delays and periodic communication loss during LEO, Lunar and
Mars missions.
Constellation requires:• The use of a framework of data transfer mechanisms to exchange
configuration metadata.• Definition of COMMAND and TELEMETRY protocols. • A Layered Approach to allow for the eventual introduction of a
Delay/Disruption Tolerant Networking (DTN) layer
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Mission Support Operations ContractConstellation protocol stack
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Mission Support Operations ContractTelemetry Configuration Control Protocol
Problem:
Telemetry configuration data must be synchronized between GC and the vehicle over a lossy and long-delay link to ensure a consistent data marshalling scheme
Constraints:
Scheme changes can be initiated by
- Ground Control- Vehicle
Proposed Solution:• In-band control loop with a circulating token between GC and the
vehicle• Single control and data FIFO• Pre-stages configuration data at initiating GC endpoint• Can operate as single stage or 2-stage commit
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Mission Support Operations Contract
Browser GUI
2-Stage Commit Telemetry Configuration Change
Pre- Stage PID,VID
Server
5 8
UPLINK DOWNLINK
Send TxID: Create Meta by PID 7Receive: Create TxID, PID
Commit
Vehicle scheme
On-board: PID, stateless
Planner
Metadata, PID
1 2 3
CREATE PID
Validation
Planning
Approval
4
PID ready
Approver
Vehicle schema VID
Data Model Keys:
Vehicle ID -VID
Metadata ID – PID
Reconfiguration
Administration Events
1-4: Bandwidth VALIDATE/APPROVE
Operational Events
5.Sends CREATE TxID, PID, Meta, VID
6. PRE-STAGE PID
7. Receive CREATE TxID
8. COMMIT TxID
TELCOM User GUI
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Ground Control
Spacecraft
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Mission Support Operations ContractLifetime of a circular token
Create: PID=1,TID=1
Metadata
Uplink FIFO
Protocol state machine
On-board
TLM:PID=0
TLM: PID=1
Downlink FIFO
Create:PID=1,TID=1
Ground Control
Protocol State Machine User Actions:
Create, Read, Update, Delete
Commit
Data
ApplicationTLM Configuration
To be defined
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Mission Support Operations ContractSummary and next steps
We have outlined a new Command and Control application protocol:• Provides services to applications – to manage changes in dataflow• Should be layered on top of TCP, UDP or DTN• Synchronizes peers by using in-band circular token• Allows 2-stage commit command execution
Next steps:• Research MOD/Constellation requirements to identify areas where this
application protocol will automate Constellation operations• Find a home to further define a Constellation application protocol
framework standard • Define additional protocol usage cases• Produce application framework specification draft
