Space-based DTN

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Glenn Research Center Networks & Architectures BranchCommunications Technology

IETF73 - IRTF DTNRG Meeting November 2008

Space-based DTNLow Earth Orbit Results

NASA PlansCCSDS Plans

Will Ivancic, [email protected]

http://roland.grc.nasa.gov/~ivancic/papers_presentations/2008/IETF73_IRTF_DTN.ppt

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VMOC

NOCNOCNOC

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Stored data transferred to

ground Sensor

1Seismic Sensor alerts VMOC

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Space Sensor acquires data (e.g. image)

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4

4

Network Control Center

Configures Spacecraft via

VMOC

VMOC negotiates for ground station services

VMOC negotiates for ground station services

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VMOC negotiates for Space Assets

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3


Configures Ground Assets


Configures Ground Assets

Stored data transferred to ground (Large file transfer over multiple

ground stations)

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Secure Autonomous Integrated Controller for Distributed Sensor Webs

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DTN Test Plan

• Goal– Demonstrate DTN Bundle Transfer from UK-DMC to SSTL Ground

Station– Demonstrate that DTN code and general SSTL code can coexist

without affecting normal SSTL Operations

• Configuration– UK-DMC acquired a150 Mbyte image Cape of Good Hope, South

Africa using the DTN SSDR code. DTN bundling code default set to 80 Mbytes for proactive fragmentation

• Tests1. Basic file download using existing technique (GRC implementation

of Saratoga version 0)2. Same file downloaded but treated as single bundle (DTN)3. Same file download but using DTN proactive fragmentation with 80

Mbytes preconfigured fragments.4. SSTL used their Workstation and SSTL implementation of

Saratoga version 0

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UK-DMC Implementation

Only Bundling and Forwarding

Implemented

Full DTN Protocol Implemented

Surrey Satellite Tech Ltd (SSTL)

Saratoga Client

Test 4

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Bundles on UK-DMC

Payload

DTN Metadata

Proactive Fragmentation Metadata - N

Proactive Fragmentation Metadata - 0

70 - 80 bytes

70 - 80 bytes

70 bytes

70 - 80 bytes

No

t to

Sca

le

150 Mbytes

80 MB

70 MB

N=2

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Palm Island Resort, Dubai, 14 Dec 2003 (UK-DMC)

www.dmcii.com

The Cape of Good Hope and False Bay. False colours – red is vegetation. Taken by UK-DMC satellite on the morning of Wednesday, 27 August 2008.

Downloaded using bundling over Saratoga, with proactive fragmentation. Fragments assembled at NASA Glenn, then postprocessed at SSTL.

First sensor imagery delivered by bundles from space.

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Checksums were very useful

• We implemented manual MD5 checksums over the payload– Greatly aided in debugging

• Identified errors in our Saratoga transport protocol implementation

• Allowed us to prove data was transmitted correctly received without errors – Used for full bundle and reconstituted bundle fragments checking

– 150 Mbytes is a bit to much to manually check

– Checksums can take significant time relative to a satellite pass, thus, we made it a command option• Apparently sometimes SSTL dumps an image and takes

another during the same pass (8 – 12 minutes).

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NASA DTN Fight Readiness by 2011

• Multi-Center Program– JPL, APL, MSFC, JSC, GRC, MSFC, University of Colorado

• Multiple Flight Implementations of RFC 5050 and LTP– JPL, Applied Physics Lab, Goddard Space Flight Center

• Flight Tests– Deep Impact (JPL)– ISS (Bioserve – University of Colorado)

• Desire to get Operations people involved

• Multi-Center DTN Engineering Testbed (DEN)– Strawman Scenarios (Low Earth Orbit, Lunar, Deep Space such as

Mars)

• Technology Development / Research– Network Management

• Also work with DARPA (BBN)• GRC plans to work with DTNRG

– Naming and Routing– Security Issues

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Multi-Center DTN Testbed

GRC plans to put DTN

machines on the OpenNet

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Consultative Committee for Space Data Systems

(CCSDS)

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Organization

• CCSDS consists of Member Agencies, Observer Agencies, Associates and Liaisons.

• A CCSDS Member Agency is a governmental or quasi-governmental organization – Only one agency representing a given country or

multinational organization may participate as a Member Agency of the CCSDS.

– Each CCSDS Agency must formally appoint its delegates to the CCSDS technical Working Groups which that Agency supports

Opinion/ObservationCCSDS patterns itself partially after ITU and partially after IETF

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Organization

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CCSDS Colors / Books

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Space Internetworking Services (SIS) - DTN

• Goal – Determine whether or not “Delay-Tolerant Networking” as specified in

RFC5050 is a feasible solution for a store-and-forward networking protocol for space environments where data relay is likely.• If RFC5050 is lacking in certain specific capabilities, this working

group may define extensions to RFC5050 to address these needs. • If RFC5050 is not suitable, attempt to define an alternate protocol

that meets the needs of the space community.– Use LTP as Transport Protocol– Additional protocols are required in order to provide a complete, working

network. The working group will also produce the following documents:• A Blue Book covering DTN naming and addressing conventions to

be used.• A Blue Book specifying one or more routing protocol(s) to be used

by DTN. • A Magenta Book describing DTN use cases and advice for

applications designers and mission planners.

Great Desire to use RFC 5050 as is in order to speed standardization and maintain interoperability with Earth terrestrial DTNs

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SIS-DTN Schedule (Proposed)

• Spring 2008 CCSDS Meetings Concept paper for discussion.• Fall 2008 CCSDS Meetings

– Green-1 book describing rationale / scenarios / use cases used to evaluate – Red-1 protocols.

• Spring 2009 CCSDS Meetings – Green-2 Book. Goal is to submit this into the publication process by summer 2009.– Red-1 book describing CCSDS Delay-Tolerant Networking protocol – Red-1 book describing reliable hop-by-hop protocol.– Begin initial implementation development as needed.

• Fall 2009 CCSDS Meetings– Final Green Book Approved describing rationale / scenarios / use cases used to evaluate .– Magenta-1 book on advice to application designers and mission planners.– Red-1 book describing naming / addressing conventions.– Begin initial interoperability testing of implementations.

• Spring 2010 CCSDS Meetings– Red-2 Book for CCSDS Delay-Tolerant Networking protocol– Red-2 Book for reliable hop-by-hop protocol.Red-1 books describing DTN routing protocol.

• Fall 2010 CCSDS Meetings– Magenta-2 book on advice to application designers and mission planners.– Second round interoperability testing of DTN and reliable hop-by-hop protocols.

• Spring 2011 CCSDS Meetings– Blue-1 Recommendations (DTN and reliable hop-by-hop)– Red-2 books describing naming / addressing conventions– Red-2 books describing DTN routing protocol.

• Fall 2011 CCSDS Meetings– Final Magenta book on advice to application designers and mission planners.

• Spring 2012 CCSDS Meetings– Blue-1 Recommendation for naming / addressing– Blue-1 Recommendation for routing protocol(s).

Space-based DTN

Documents