Optical Link Study GroupReportCCSDS

Optical Communications BOF

John Rush (NASA) and Klaus-Juergen Schulz (ESA)October, 2013

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• Introduction• OLSG Objective• Schedule of Agency Optical Communications

Demonstrations• OLSG Final Report Review and Findings• IOAG-16 Action Results• Next Step: IOP-3 Briefing Overview

Agenda

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• Numerous IOAG Agencies are experimenting with Optical Communications, and starting first operational capability

– Optical Communications is in early stage development – Agencies are experimenting with different techniques– ESA/DLR starting earth relay services with EDRS/Sentinel

• In 2010 the OLSG was chartered by the IOAG to determine if there was a business case for Cross Support in Optical Communication and it was determined that there is such a case.

• The OLSG was formed with seven member Agencies: ASI, CNES, DLR, ESA, JAXA, KASI, and NASA.

• The IOAG requested that OLSG do further studies to identify the types of standards that would be needed to enable Cross Support in Optical Communication

• The OLSG is reported its findings to IOAG-17 and the IOAG-17 brought forward a recommendation to IOP-3 in June of this year.

Introduction

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OLSG Process

• Surveyed existing optical communications projects among the agencies

• Identified significant issue in dealing with Atmospheric conditions (i.e. clouds, optical turbulence) and began detailed study of how to improve availability

• Developed scenarios in order to prove feasibility based on statistical analysis of cloud data for scenario ground terminal locations

• Identified guidance for the development of cross support standards

2013Technology Demonstrations

20202014 2015 2016 20172012 2025

OPALS (NASA)• ISS-ground demo• 1553 nm, OOK

modulation

LLCD (NASA)• 2013 Moon-Earth

demo• 1550 nm, single

photon detection and PPM

LCRD (NASA)• 2017 GEO-Ground

and ISL LEO-GEO• 1550 nm, direct

detection PPM

LCT-135/Alphasat (ESA)• 2013 ISL, GEO to

Earth demo• 1064 nm,

Homodyne BPSK

Sentinel/EDRS (ESA)• 2014 ISL• 1064 nm, Homodyne

BPSK

Optel-µ (ESA)• 2017 LEO-Earth

demo• direct detection

and PPM

TerraSar-X (DLR)• 2009 LEO-ground

demo• 1064 nm,

Homodyne BPSK

DOT (NASA)• 2020 Mars-ground• 1550nm, direct

detection PPM

TerraSar-X (DLR) to NFIRE (USAF)• 2008 ISL LEO-LEO

demo• 1064 nm,

Homodyne BPSK

OSIRIS (DLR-ICAN)• 2014 LEO-Earth demo• 1550 nm, IMDD

Agencies Already Engaging in Optical Communications Experiments

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SOTA (NICT)• LEO to ground

demo• 1064 and 1550nm,

OOK modulation

TDRS (NASA)• 2025 GEO-Ground

Operational Relay• 1550 nm, DPSK

and high speed routing

Analysis of Availability

• Developed models of various scenarios using optical communications for mission data– Assumed all missions would have RF link for

spacecraft commanding– Missions modeled after existing missions

• NASA weather model used to support analysis– Statistical model of cloud coverage– Developed yechniques for evaluating impacts of

“Cloud Free Line of Sight (CFLOS)” on mission success in terms of amount of data return

Example Scenario – L2• CONOPS:

– Modeled based on the EUCLID mission (operations always in night time)– 7.5 Tb data volume per day – 3 days of onboard storage (22.5 Tb)– 3 hr of Cloud Free Line of Sight (CFLOS) required per day– Link budget developed for 700 Mbps data rate, favorable Sun-Probe-Earth (SPE)

angle, i.e. ground terminal always looks into the dark sky.• Space Segment:

– Could be derived from LLCD or TESAT LCT-135 terminals– 13.5 cm aperture– 5 W transmit power– 50 kg, 160 W

• Ground Segment:– Terminal with 1m Rx aperture telescopes, 8x 15cm Tx telescopes with

50W/aperture– Two ground terminals: Tenerife and Ascension, Tenerife and Hartebeesthoek

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Example L2 Scenario Analysis• Link Budgets:

– Downlink Link Budget, 1m Rx aperture– Uplink Link Budget

• 8x 15cm apertures to minimize effect of atmospheric turbulence instead of radiating through the Rx aperture• Calculation of Nominal Ocular Hazard Distance (NOHD) based on continuous wave, 1550 nm , to not exceed the Maximum Permissible

Exposure (MPE) of max 0.1 W/cm2

• Laser Communications Network Optimization Tool (LNOT) computes Cloud free line of sight (CFLOS) and availability

• Overall Percentage Data Transmitted (PDT): 99.89%• Cumulative distribution of monthly PDT

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Prob

abili

ty o

f exc

eedi

ng P

DT

Space-Earth Scenario Analysis Summary

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Scenarios Unit LEO Lunar L2 L1

DeepSpace(Mars)

Single Relay Optical FL (Case b)

Scenario ConOps

Data Volume per day Tb/d 12 5.72 7.5 7.5 1.1 216Onboard Storage Tb 2.3 7.4 22.5 22.5 1.1 10

Data Rate per second Mb/s 10,000 622 700 700 0.7-260 10,000

CFLOS required per day h/d 0.33 2.55 3 3 1.2 6Onboard Terminal

Aperture cm 8 10 13.5 13.5 22 13.5Tx Power W 0.5 0.5 5 5 4 2.2Mass kg 35 30 50 50 < MRO Ka 50

Power Consumption W 120 140 160 160 < MRO Ka 160Ground Stations

Rx Terminal Size diameter m 0.4 1 1 1 12 1

Tx Apertures and Size 4x 5cm 4x 15cm 8x 15cm 8x 15cm 9x 7cm 4x 15cm

Tx NOHD ICAO (1550nm) m 451 12,111 27,080 32,042 42,125 6,055

Tx NOHD Near Field (1550nm) m 0 4,094 24,574 29,957 42,068 0

Number of Terminals 7 2 2 2 2 3

Location of Terminals

Haleakala, TMF, Madrid, Svalbard, La

Silla, Tenerife, New Norcia,

Hartebeesthoek Haleakala,

Tenerife Tenerife,

Hartebeesthoek Tenerife,

Hartebeesthoek Haleakala, TenerifeWSC, Tenerife,

La SillaPDT resulting % 94.8 97.4 99.9 98.5 99.0 98.0

Additional Study of Intersatellite Cross Links

• In addition to the main concentration of OLSG on space to ground links, intersatellite cross links were also studied

• It was found that there are two wavelengths being used, or planned for use, by the member agencies: 1064 nm and 1550 nm– OLSG believed it would be best to narrow the possible

wavelengths to these two– Further demonstrations and use of the wavelengths will

provide additional data on performance in the future but it is too early now to narrow the selection further now

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• OLSG determined that there is a business case for cross support among the IOAG Agencies

– Due to the unique disruptions to optical communication links by atmospheric conditions additional coordination of handovers to alternate ground stations is necessary and should be included in the standardization set

– Another source of potential disruption to optical communications links is caused by aircraft so a dialog should take place with the International Civil Aviation Organization (ICAO) to find ways to minimize the disruptions

• IOAG requested that OLSG conduct further analysis and assigned an Action to OLSG– Determine the new standards that must be developed by CCSDS, as well as identify the existing CCSDS

standards that can be re-used for Optical Communications Cross Support– Provide guidance for development of standards that relate to the coordination of ground optical

communication stations • Considering the exchange of necessary atmospheric conditions• Coordination of handovers from one ground station to another

– Provide a recommended IOP-3 briefing outline to IOAG-17 that presents the case for endorsement of optical communications cross support by the IOP and agreement to proceed with the standardization process

– Determine resource estimate and schedule for standardization of optical links including necessary ground coordination

OLSG Findings Presented to IOAG-16

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OLSG Findings on Reuse of Existing CCSDS Standards

• A team of optical communication experts was formed:– NASA– ESA– DLR– CNES– JAXA

• The team considered standards available at each layer and determined that everything at the CCSDS frame layer standards and above is reusable and does not have the be developed for optical communication cross support

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DELTA DORPN RANGING

Prox -1 TM, TC

LTP

DTN- BP/BSP

Channel Coding and Sync

IPv6

Space Packet Protocol

CFDPIPv4

AOS

RANGING

Encap

SECURITY

RF & Modulation

SLS AREA

DATACOMPRESSION

AOSServices

SLS AREA

Reuse existing standards for optical communications

Must be developed for optical communications cross support

Re-use of Existing Space-Ground CCSDS Standards

Guidance on New Standards• Optical CommunicationSpace to Ground Standards

• Ground stationcoordination requiresmeteorological forecastsand handover coordination

Agency A

Meteorological Data

Spac

e-Gro

und C

onne

ction

Nex

t Spa

ce-G

roun

d Co

nnec

tion

Agency BNOC AM

eteo

rolo

gica

l Da

ta

NOC B

Handover coordinationincluding meteorological data

SpacecraftMOC A

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New Optical Communication Standards Needed

• Green Book for link budgets, atmospheric models, handovers, and concept of operations

• Blue Book for low signal photon flux optical communications

• Blue Book for high signal photon flux optical communications, especially intersatellite crosslinks

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New Optical Communication Atmospheric Characterization Standards Required

• Blue Book for real-time weather and atmospheric characterization data

• The CCSDS WG should gather more information concerning the coordination and exchange of necessary atmospheric data, including collaborative effort, before finalizing the Blue Book

CCSDS Standardization Effort Estimate

• Resources (mm= man months):– 1 Green Book: 10mm– 3 Blue Books: 90mm– Total: 100mm

• Schedule:– Green Book for Link Budgets, etc: 1 yr– Low Photon Flux Blue Book: 2 yrs– High Photon Flux Blue Book: 4 yrs– Meteorological Data/forecast and handover: 4 yrs

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Green Book – common link budgets

Blue book – low photon flux

Blue book – high photon flux

Blue book – meteorological data/forecast and handover

CompleteBegin

2014 2017 2018 20192015 2016

Begin

Begin

Begin

Complete

Complete

Complete

2013

Technology Demonstrations

2020 20252014 2015

Standardization Development Optical Terminal

Development

Optical Terminal

Flight

IOP-3 June 2013

2012

IOAG-16Dec 2012

CCSDS BoFConcept Paper and CharterOct 2013

CCSDS WG Apr 2014

IOAG-15bJun 2012

OLSG Final ReportJun 2012

OLSG Standardization Guidance AddendumJul-Nov 2012

2016 2017

2012 2013 2014 2015 2016 2017 2020 2025

OPALS (NASA)• ISS-ground demo• 1553 nm, OOK

modulationLLCD (NASA)• 2013 Moon-Earth

demo• 1550 nm, single

photon detection and PPM

LCRD (NASA)• 2017 GEO-Ground

and ISL LEO-GEO• 1550 nm, direct

detection PPM, and DTN

LCT-135/Alphasat (ESA)• 2013 ISL, GEO to

Earth demo• 1064 nm,

Homodyne BPSK

Sentinel/EDRS (ESA)• 2014 ISL• 1064 nm, Homodyne

BPSK

Optel-µ (ESA)• 2017 LEO-Earth

demo• direct detection

and PPM

TerraSar-X (DLR)• 2009 LEO-ground

demo• 1064 nm,

Homodyne BPSK

DOT (NASA)• 2020 Mars-ground• 1550nm, direct

detection PPM

TerraSar-X to NFIRE (DLR)• 2008 ISL LEO-LEO

demo• 1064 nm,

Homodyne BPSK

Priority 1 Guidance for CCSDS:

OSIRIS (DLR-ICAN)• 2014 LEO-Earth demo• 1550 nm, IMDD

OLSG Recommended Standardization Schedule

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SOTA (NICT)• LEO to ground

demo• 1064 and 1550nm,

OOK modulation

1. Green Book for link budgets, atmospheric models, handovers, and concept of operations

2. Blue Book for low signal photon flux optical communications

3. Blue Book for high signal photon flux optical communications

4. Blue Book for real-time weather and atmospheric characterization data

TDRS (NASA)• 2025 GEO-

Ground Operational Relay

• 1550 nm, DPSK and high speed routing

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Optical Communications Eye Safety

• OLSG was asked to establish contact with the International Civil Aviation Organization and work to ensure that the optical communications uplink budget in various scenarios (LEO, GEO, GEO Relay, Lunar, L1, L2, and Mars) were eye safe to maximum extent possible

• OLSG discovered several barriers to complete eye safety for optical communications, including maximum permissible exposure (MPE) thresholds, irradiance at aperture, near field effects, and time spent in the beam, all of which factor into ICAO standards (also ANSI and IEC standard)

• ICAO welcomes further dialogue and education on optical communications from all international agencies that will be utilizing this technology in the future to create an eye safe operational environment

• It is recommended that IOAG develop a Liaison with ICAO for the purpose of minimizing restrictions on aviation eye safety rules to allow minimum impact of optical communication ground stations, yet ensuring an eye safe operational environment

• Initial discussions begun with astronaut office responsible for eye safety and it is recommended that a continuing dialog take place with the objective of defining specific requirements for astronaut eye safety

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IOP-3 Communique

The IOP-3 encourages the member agencies to prepare for optical communications as the next evolution of space communications; therefore:

1. The IOP recognizes the good work of the OLSG and the benefits of developinginteroperability in the domain of optical communications.2. The IOP recommends that the member agencies begin preparing for future cross supportof space-Earth and space-space optical communications by developing interoperablestandards.3. The IOAG is requested to provide guidance to CCSDS in the development of the requiredstandards.4. The IOP urges collaboration on demonstrations, and experiments that may be useful inthe standardization and the development of optical communications technology.5. The IOP member agencies are encouraged to share with other IOAG members theirtechnical and operational experience.6. The IOP recommends assessing the results of the upcoming technology demo missions toverify the feasibility of a common wavelength for a future intersatellite link in the contextof a data relay system in order to facilitate interoperability. This would be similar to theconcept of the Space Network Interoperability Panel (SNIP) approach.7. The IOAG is requested to report progress in the optical communications cross supportarea at IOP-4.