The CCSDS Cislunar Communications Architecture Keith Scott The MITRE Corporation CCSDS Meeting January 2007

Agenda CCSDS Cislunar Space Internetworking Working Group Scope and Charter Current Mission Architecture Future Mission Scenarios Networked Communications Terrestrial Interoperability

CCSDS Cislunar Space Internetworking Working Group Chartered to produce a communications architecture for cislunar (between the Earth and the Moon) communications –Includes robotic Earth-observing and lunar missions –Includes crewed Earth-orbital and lunar missions –Where possible, should extend to comparable in-situ environments

Current Mission Architecture RF 1553 InstSubsysInst CCSDS AOS, TC, TC/TM Space Link Extensions C&DH MCC

Future Missions?

Proximity Link: Frequency band Comm protocols Multiple Access Scheme Orbiter Deep Space Link: Data rate (~power x gain) Frequency (X, Ka) Range variation (25x comm performance) Current Relay Comms Adapted from Wallace Tai’s IOAG presentation, June 2004

Proximity Link Orbiter Deep Space Link Current Relay Comms Adapted from Wallace Tai’s IOAG presentation, June 2004 Application

Networked Communications Multi-Hop –“Route around” obstructions –Heterogeneous links tuned to the environment Global Addressing –Applications don’t have to worry about where the destinations are or how to get there Automated data forwarding –Fewer commanded data movements Efficient multiplexing of many applications Data Link Physical Data Link Physical Data Link Physical Data Link Physical Application Network

Forwarding IP Packets / / / / DestinationNext Hop / / /

Routing Protocols / / / /16 I can reach /16 I can reach /16 I can reach /16 I can reach /16, /16 I can reach /16 I can reach / /16

Mixed Architectures Applications should still have access to data-link-specific services, they just aren’t end-to-end services Data Link Physical Data Link Physical Data Link Physical Data Link Physical Application Network Application

Which Network Layer? Choices include –IP –ATM –IPX –AppleTalk –… Advantages of IP –NOT connection-oriented (don’t need end-to-end signaling to set up path) –Wide availability of implementations / hardware Including small implementations suitable for flight software –Interoperability with ground infrastructure Simplifies testing / verification

Other Topics in Green Book Quality of Service Security Emergency Commanding Overlay Communications

Terrestrial Data Transport What support is needed in the ground infrastructure to support IP-based missions? Spacecraft built by AgencyA that uses IP networking using AgencyB’s ground station –Several options, depending on ground station capabilities and inter-agency connectivity characteristics Space Link Extensions return-all-frames and return-channel-frames services being prototyped now by NASA, ESA, JAXA Direct routed IP from the ground station –What changes would this require at ground stations? –What are the constraints on inter-agency connections (security, QoS)? Tunnel IP datagrams from ground station to mission operations –What changes would this require at ground stations? –What are the constraints on inter-agency connections (security, QoS)?

G/S AOS SLE AOS CCSDS Space Packets Interoperability Via SLE CCSDS VC SPData AOS S/CMCC SPData CCSDS VC AOS SLE PayloadSLEIPSLE PayloadSLEIPSLE PayloadIPSLE Space link terminates at MCC SLE characteristics (latency, jitter) are considered part of the space link characteristics IP datagrams, CCSDS Space Packets, … SLE doesn’t care SPDataSPData

G/S AOS SLE AOS IP Packets Interoperability Via SLE CCSDS VC IPData AOS S/CMCC IP Network IPData CCSDS VC AOS SLE PayloadSLEIPSLE PayloadSLEIPSLE PayloadIPSLE Space link terminates at MCC SLE characteristics (latency, jitter) are considered part of the space link characteristics Can mix IP and Space Packets IP Packets IPDataIPData SPDataSPData

G/S AOS SLE AOS IP Packets CCSDS Space Packets Interoperability Via SLE CCSDS VC IPData AOS S/CMCC IP Network IPData CCSDS VC AOS SLE PayloadSLEIPSLE PayloadSLEIPSLE PayloadIPSLE Space link terminates at MCC SLE characteristics (latency, jitter) are considered part of the space link characteristics Can mix IP and Space Packets IP Packets IPDataIPData

G/S IP GRE IP AOS IP Packets IP Tunnel CCSDS Channel IPData AOS S/CMCC IP Network IPData CCSDS Channel AOS Space link terminates at Ground Station Forces traffic through Mission Control Center Different latency / jitter characteristics than SLE tunnel IP Packets IPDataIPDataIPDataIPData GRE IP

AOS IP Packets Downlink Return Via IP CCSDS VC IPData AOS S/CG/S IP Network IPData CCSDS VC AOS IP Packets Space link terminates at the ground station IP traffic delivery over the inter-agency cloud Implications for security / uplink stream formation IPDataIPData MCC IP Packets

AOS SLE AOS IP Packets CCSDS Space Packets Mixed Approach CCSDS VC IPData AOS S/CG/SMCC IP Network IPData CCSDS VC AOS SLE PayloadSLEIPSLE PayloadSLEIP CCSDS Space Packets IP Packets The approaches above can be mixed. SLE PayloadIPSLE IP Packets

Conclusions A network layer unifies possibly heterogeneous data links Automated data forwarding simplifies operations over what we do now or might do using current protocols An IP-based system leverages commercial technologies and can leverage the terrestrial infrastructure An IP-based infrastructure can handle the range of data types we currently envision and has shown flexibility in the past The technical issues with an IP infrastructure in space are addressable It’s possible to mix-and-match new routing components alongside traditional operations in the same spacecraft and terrestrial systems

Status Green book (architecture) done and about to be submitted to CESG for review (final editing completed last week) Starting first Recommendation dealing with ‘simple’ IP- based spacecraft operations –Focus on terrestrial interoperability

Questions?

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