ISS Institutional DTN Overview for CCSDS

Adam SchlesingerNASA – JSC

October 30, 2013

Institutional DTN Objectives

• Develop an ISS DTN Architecture for flight, ground, and test/simulation systems (includes MSFC, MCC-H, and SCTF/SDIL)

• Increase reliability of payload data transfers between ISS and remote payload control centers during AOS/LOS transitions

• Increase automation of Payload Developer (PD) requests for data transfers

• Alleviate extensive support to plan payload transfers around AOS/LOS and operator required transfers

• Use standard, publicly available protocols, avoiding the use of costly custom protocol implementations

• Upgrade SWRDFSH file transfer application to use CFDP over DTN, improving bandwidth efficiency and enhancing QoS

Note: Targeting March 2015 for on-orbit availability

ISS System Implementation Architecture

• Two nodes onboard on SSC File Servers accessible by both Payloads and Operations Userso One serves as Operations Primary and Payloads Backupo One serves as Payloads Primary and Operations Backupo Nodes will be ION

• Two nodes at MCC-Ho One Primary and One Backup for Operationso Nodes will be ION

• Two nodes at MSFC-HOSCo One Primary and One Backup for Payloadso Nodes will be DTN2

Note: MCC-H and MSFC-HOSC nodes will provide additional redundancy for Payloads and Operations

Current Payload Operations

• Uplink/Downlink request via HOSC support

• Entire files have to be re-transmitted when transfer errors occur

• Manual transfer by operations required for file transfers across AOS/LOS

• 24x7 continuous support operations to ensure access to science data

• Recorded data requires operators to initiate playback

• Custom file transfer protocols utilized. Currently each payload, tool, support equipment uses a custom method or protocol to transfer data reliably between on-orbit and ground

DTN Benefits For Payloads

• Provides capability for Payload Developers (PDs) to automate operations and ensure science delivery with little regard for link or facility outages o PDs can request files for up/down link without HOSC supporto HOSC and ISS DTN nodes will store user file uplinks/downlinks and forward bundles as Ku-band becomes

availableo HOSC DTN node will also store user telemetry and forward it to the PD site when it comes back online

• Reduce PD real-time support to access and downlink science datao DTN stores data during LOS and automatically initiates transfer upon AOSo A download transfer can span Ku-Band AOS periods without any special scheduling or scriptingo Reduces need for duplicate storage and extra retrieval actions

• Reliable data transfer for ISS during LOS/AOS cycleso Automatic verification of bundle receipts, retransmissions reducedo When transmission errors occur only the bundles that have errors are retransmittedo Maximizes use of bandwidth by reducing the amount of data that has to be retransmitted

• Allows PDs to use DTN protocols for their own applications (streaming, telemetry, etc.)

• Efficient use of downlink stream through DTN Quality of Service (QoS) / prioritization

• Tolerance for high network latency

Current and Future Use Cases for ISS DTN

• Current Users of DTN on ISS:— Various “developmental” DTN configurations have been in use on ISS in support of payload

activities for several years— DTN is currently being used in support of the following Payloads

• BioServe Commercial-Grade Bioprocessing Apparatus (CGBA)• DARPA Synchronized Position Hold Engage and Reorient Experimental Satellites

(SPHERES) Smartphone• ESA Quickstart and OPSCOM I

• Additional Payloads discussing use of DTN include:— Multiple User System for Earth Sensing (MUSES)— GRC SCaN TestBed – CoNNeCT— ESA’s METERON (Multi-Purpose End-To-End Robotic Operation Network) – OPSCOM II— HET Surface Telerobotics— JAXA interest in collaborating with NASA to implement Kibo DTN Project— Hyperspectral Imager for the Coastal Ocean Experiment Payload (HREP)— Other payloads are interested based upon availability for service to be implemented

DTN Example Benefits for Specific Payloads

Payload Potential Benefits Provided by DTN

MUSES Automated and bandwidth efficient file transfers of bulk data (HD video and files)

SCaN TestBed Automated, reliable and bandwidth efficient transfer of data in the presence of short passes for the direct-to-ground link

ESA METERON/OPSCOM II Reliable transfer of command and control plans for robots and prioritized streaming of situational awareness video

Human Exploration Telerobotics

Reliable transfer of command and control plans for robots and prioritized streaming of situational awareness video

JAXA Kibo Automated, reliable and bandwidth efficient data transfer using DRTS as well as interoperability with NASA assets using a standard protocol

HREP Automated, bandwidth efficiency and prioritized file transfers of bulk data (hyperspectral images)

• Note: The bandwidth efficiency of each individual payload using DTN allows for more available bandwidth and more science return for all payloads

Summary

• The implementation of DTN on ISS will provide a standard method of communication for payloads that is reliable, autonomous and more efficient than current techniques, resulting in better utilization and more science return from ISS

• The use of DTN by payloads will significantly ease PD development of both onboard and ground communication systems and could reduce payload operator costs