Jim Schier, Chief Architect and Dep. Director System EngineeringSpace Communications and Navigation Program17 Oct 2016

NASA’s Next Generation Space Communications Architecture Concept

Ka-Band and International Communication Satellite Systems Conferences

Background for Current Studies

• Studies started in 2013 to define future NASA Communications & Navigation (C&N) architecture and evolutionary path– Established that current networks have sufficient stability

for 15+ years to enable a new Next Generation Architecture to be introduced

• Current effort intended to complete the process well enough to support NASA budget process and collaborate with national, international, and commercial stakeholders:– Earth Network: TDRSS fleet capacity drops enough to

require new capacity starting in ~2025

– Mars Network: In addition to Mars 2022 mission, Mars Network concept must be planned to meet HEOMD and SMD needs

– Optical communication: Transition joint MD investment in optical communication to Operations

• Study contracts awarded to industry for input to ensure thorough assessment of concepts and capabilities before decisions are made

• Vision and architecture concepts presented today are work in progress

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Vision

• “Shrink” the solar system by connecting the principle investigator more closely to the instrument, the mission controller to the spacecraft, and the astronaut to the audience

• Improve the mission’s experience and reduce mission burden – the effort and cost required to design and operate spacecraft to receive services from the SCaN Network

• Reduce network burden – the effort and cost required to design, operate, and sustain the SCaN Network as it provides services to missions with the collateral benefit of increasing funding for C&N technology

• Apply new and enhanced capabilities of terrestrial telecommunications and navigation to space leveraging other organizations’ investments

• Enable growth of the domestic commercial space market to provide – and NASA to use – commercial services currently dominated by government capabilities

• Enable greater international collaboration and lower costs in space by establishing an open architecture with interoperable services that foster commercial competition and can be adopted by international agencies and as well as NASA

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Paradigm Shifts

• RF RF + Optical• Point-to-point (Connection-oriented, single access)

links broadband (connectionless, multiple access)

• Scheduled access unscheduled access• Phase over from Ku-band as near Earth backbone Ka-band (phase out Ku-band)

• Link layer service provider network service provider

• Different near Earth and deep space architectures common architecture

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Shift: RF RF + Optical

• Transition Laser Comm Relay Demo (LCRD) to operations after 2019-2021 demonstration phase for initial Earth Network optical capability by ~2021

• LEO terminal being developed for ISS as 1st user• Discovery AO incentivized bidders for deep

space optical– 3 of 5 bids selected chose to include an optical

payload

• Optical technology promises– High data rates with low SWaP and cost for users

and relays

– Optical platform’s built-in vibration isolation reduces impact on spacecraft bus of gimbaled antenna

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Single Access Multiple Access

• Under-utilization: Missions use TDRSS Single Access at a fraction of capacity

– Demand access: user requests access when he needs it and gets BW that he needs

• Single Access points one network antenna to one user antenna and commits both for duration of event connection-oriented like telephone switchboards

• Multiple Access enables one network antenna to talk to multiple users simultaneously in same overall system bandwidth

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NENDSN

Dedicated Space-Ground Link to Ground Terminal

User-TDRS SA Link for Event

TDRS

User-Network Link for Event

NENDSN

DSN: • Multiple S/C Per Antenna (MSPA)• Opportunistic MSPANEN: TBD

Dedicated Space-Ground Link to Ground Terminal

User-TDRS MA Links for Events

Future Space Relay

Shift: Scheduled Unscheduled Access

• All missions schedule events (passes) days-weeks in advance – Process is labor-intensive

• Unreliable data delivery forces missions to schedule extra events and repeat transmissions– Scheduling is NP-hard – TDRSS schedules ~60%

efficient

• Approach:– Expand use of Multiple Access; reduce Single

Access

– Introduce demand access services

– Shift from (unreliable) link layer to (guaranteed) network layer service using Disruption Tolerant Networking (DTN)

• Result: Eliminate scheduling for most missions– Enables further system automation and operations

cost reduction

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Shift: Switch from Ku- Ka-band

• Spectrum pressure: NASA agreed to NTIA direction to move out of Ku-band space-to-space (eventually)– NASA incorporated Ka-band starting with TDRS H (2000)

– NASA also obtained Ka-band space-to-ground allocation

• Ka-band can provide higher data rates at higher frequencies with lower spacecraft SWaP – Need to bring cost down and increase coverage to

overcome user community reluctance to adopt Ka

• Eliminate Ku-band from Next Gen Earth Relay8

Services: Link Layer Network Layer

• Link layer services don’t guarantee data delivery – Mission Operations Centers (MOC)

develop SW to process data for errors, resend data, command s/c when to delete data from memory

– Application layer protocols such as CCSDS File Delivery Protocol (CFDP) with Automatic Repeat Request (ARQ) provide reliable delivery over unreliable link layer protocols such as Space Packet

• Expand services to include space inter­networking (Solar System Internet, SSI, using IP and DTN)– DTN guarantees delivery obviating need

for MOC processing and retransmission reducing burden on both user ground and flight segments

• SSI enables a Service-Oriented Architecture (SOA) that can provide many added apps

• Data can move directly from MOC/MCC to PI or directly from spacecraft to PI

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Current SCaN Network Service

Future SCaN SSI Service

Standardized Service Architecture

Services – 2015 era Services - 2025 era Services – 2040 era Forward data delivery Return data delivery Radiometric data Science services

o Radaro Radio Scienceo VLBI/Radio

astronomy

Forward data delivery Return data delivery Radiometric data Science services

o Radaro Radio scienceo VLBI/Radio

astronomy Network layer services

(IOC) End-to-end file service

(IOC) Optimetric data (IOC) Time delivery (IOC) Positioning (IOC) Space link layer service

(IOC)

Forward data delivery Return data delivery Radiometric data Science services

o Radaro Radio scienceo VLBI/Radio astronomy

Network layer services (all networks) End-to-end file service (all networks) Optimetric data (all networks) Time delivery (all networks) Positioning (all networks) Space link layer service (all networks) End-to-end messaging service (all

networks) Service-Oriented Architecture (SOA)

services (by Earth ground stations) Celeslocation service (by planetary

networks with positioning capability)

LEGEND: Green Text indicates New Services Types or extended capability; Red Text indicates Old Service Types supported on existing spacecraft but not offered for new spacecraft 10

Planetary Networks: Earth, Moon and Mars – One Architecture

11Architect for Flexibility, Scalability, and Affordability – Implement as required to meet specific mission needs

Deep Space Habitat

GEO HMO

LMOLEO

Trunk link Proximity

Links

SCGS

Trunk link

Proximity Links

Earth Relay Mars Relay

Science Orbiter

Science/ Relay Orbiter

Lander

Phobos Exploration Vehicle

Earth Network Mars Network

HLO

LLO

Proximity Links

Lunar Relay

Science/ Relay Orbiter

Science Orbiter

Lander

Lunar Network

Exploration Habitat

Distant Retrograde Orbit (DRO)

Trunk link

DTE/ DFE

Benefits of Planetary Networks:• Reduced mission burden with short links for in-system communications - enables in-system telerobotics• Common architecture reduces technology and development costs• Reuse of HW and SW: Family of products includes variants for different environments• Reuse of spectrum – migrate to Ka-band and away from Ku-band

Planetary Networks:Global Interoperable Contributions

• Planetary Network includes:– NASA networks or assets

– Commercial Service Provider (CSP) network(s)

– International partner network(s)

– Other government systems: GPS, GNSS

– Academic partner assets

• Planetary Networks are based on open architecture using international standards at interfaces – Permits cross support between international partners

– Provides on-ramps for CSPs and lower cost COTS HW and SW

– Like terrestrial communication networks, run over common Layer 3 (Network layer) services

– Maximize commonality of services across near Earth and deep space domains

• Already well advanced through IOAG and CCSDS

– Use SW Defined Radios (SDR) to promote common radio HW and SW across domains

– Use cognitive networking to manage any network anywhere

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Conclusion

• Studies have identified strategies to define a broad evolutionary path for space communications and navigation– Elements of Vision define major thrusts

– Projected mission needs define key performance characteristics

– Technology roadmap defines approach to achieving performance that enable capabilities

– Architecture including services, interfaces, and ConOps define broad physical and operational approach to providing capabilities

• Next Gen Architecture will be baselined in 2018-19 with initial capability by mid-2020s– Coordination with government, international and

industry partners is underway

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https://www.nasa.gov/scan

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Twitter: @NASASCaNEyes on the DSN: http://eyes.nasa.gov/dsn/dsn.html

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