NASA Infrastructure Capabilities to Support NearEarth Missions

1
NASA Infrastructure Capabilities to Support
Near-Earth Missions

• 16 July 2002

2
Purpose of Briefing

• Identify existing NASA and commercial ground and
  space capabilities
• Identify the constraints associated with use of
  the current allocated spectrum
• Define possible architecture for communications
  support to future earth science high data rate
  missions
• Identify available technology to support future
  high data rate missions operations at Ka-band

3
Background

• Future near-earth science missions want
• Higher data rates for space-to-ground data
  transfer
• Minimize data latency
• Lower cost communications subsystems with reduced
  size and weight
• Availability of adequate RF spectrum to support
  these goals is of significant interest because
  of
• Increasing RF congestion in allocated bands (S,
  X, and Ku-bands)
• Continuing increase in mission downlink data rate
  requirements beyond capacity of existing
  allocations

4
Infrastructure Overview

• Earth Exploration Satellite (EES) data
  communications can be accomplished via
• Direct link with a ground terminal, such as
  NASAs Ground Network (GN)and/or
• Through a relay satellite system, such as NASAs
  Tracking and Data Relay Satellite System (TDRSS)
• Infrastructure to support these services can be
  provided through several sources, such as
• Government resources, such as the Ground Network
  and TDRSS
• Commercial resources, such as Datalynx and
  Universal SpaceNet
• Mission-dedicated ground terminal

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Ground Network
Svalbard, Norway NSC
Poker Flat, Alaska DATALYNX
Sweden
USN
USN
Wallops Island
University of Alaska, Fairbanks
Merritt Island, Ponce De Leon
Hawaii
USN
South Africa
USN
Perth
USN
Santiago U of Chile
McMurdo Station, Antarctica
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Available X-band Ground Network Infrastructure
Summary

• List may not be all
  encompassing (i.e., does not include DSN stations
  as well as other all foreign stations)

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NASAs Space Network
TDRS Constellation
GODDARD SPACE FLIGHT CENTER
WHITE SANDS COMPLEX
GUAM REMOTE GROUND TERMINAL
F-5 174W TDW
F-7 171W (in-storage)
F-6 047W TDS
TDRS- F8 171W
F-4 041W TDE
F-3 275W TDZ

• TDRS-I undergoing transfer orbit correction
• TDRS-J scheduled for launch late 2002
• The SN is composed of the Space Segment,
  consisting of the Tracking and Data Relay
  Satellites (TDRS), and the Ground Segment,
  consisting of ground stations located in White
  Sands, New Mexico and Guam and other supporting
  subsystems.

8
NASAs Space Network Capabilities
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Infrastructure/Spectrum Allocation Summary
10
Current and Projected X-Band Missions Using
Polar Ground Station Resources
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Future High Data Rate EES Missions
Mission
Code
Data Transfer Req.
Orbit
Missions
S/C Per
Description
Per
Mission
Timeframe
Earth Orbital
NEAR TERM MISSIONS(2005-2010)
Earth Orbital
MID TERM MISSIONS(2010-2015)
Earth Orbital
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Current Ka Frequency Allocations

• NASA spectrum managers encouraging medium and
  high data rate, near-earth missions to utilize RF
  allocation at Ka-band
• Supports higher data rates due to larger
  space-to-earth allocation for earth-exploration
  satellites
• Allows smaller, lighter spacecraft components
  (e.g., antennas)
• Affords missions the flexibility of using a wide
  bandwidth space-to-space link via the TDRS H,I,J
  Ka-band service (backup support)

Ka-Band Allocations for TDRS H,I,J Return Service
and Direct-to-Ground Communications

INTER-SATELLITE SERVICE
EARTH-EXPLORATION SATELLITE SERVICE (s-e)
27 GHz
25.5 GHz
27.5 GHz
25.25 GHz
NOTE The addition of a primary allocation for
Space Research Service in the 25.5 - 27.0 GHz
band will be considered at the next World Radio
Conference (WRC) in 2003.
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X-Band vs. Ka-Band Comparison
14
X-Band vs. Ka-Band Comparison (contd)
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Possible Ka-Band Ground Terminal Configuration

• Possible Ka-band configuration to support
  high-inclination, near-earth spacecraft
• Co-locate Ka-band ground (receive only) station
  with existing S/X-band ground stations at high
  inclination sites (e.g., Alaska and Norway)
• Use existing S-band capability for TTC,
  initially
• Cost savings through use of existing ground
  station infrastructure
• Use Ka-band receive capability for EESS data (up
  to at least 600 Mbps, initially)
• Provide hooks (e.g., link margin) for future
  addition of Ka-band downlink data rates greater
  than 1Gbps and S-band TTC capability
• Possible Ka-band technical characteristics
• 25.5 - 27 GHz frequency band
• BPSK and QPSK modulation, initially
• 5-meter class ground terminal antenna capable of
  supporting overhead passes
• Can support space-to-earth data rates from 600
  Mbps - 1 Gbps for a 33 dBWi spacecraft EIRP
• On-site data storage and rate buffering (use T3
  to offload data)

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Ka-Band Technology Considerations

• No new or high-risk technologies required for a
  Ka-band Ground Terminal (for downlink reception)
• Technology developments at GSFC can be leveraged
  for space and ground Ka-band systems
• Ka-Band Transition Project (KaTP) uses
• 5.4m S/Ka-band demonstration ground station
  located at WFF
• WSC modifications to support wide-band (650 MHz)
  KaSAR customers
• High data rate SN and GN demonstrations (600
  Mbps)
• Ka Upconverter and Modulator (QPSK, 150 Mbps)
• Ka-Band Phased Array S/C Antenna (33 dBWi EIRP)
• High Data Rate Parallel Digital Ground Receiver
  (QPSK, 600 Mbps)
• High Data Rate Digital Modulator (multiple
  modulations, 1 Gbps)

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Ka-Band Technology Considerations (contd)

• GSFC contacted commercial vendors to assess the
  availability of Ka-band spacecraft hardware
• Solicited information (RFI) for a high rate
  spacecraft modulator (600 Mbps using QPSK, 800
  Mbps using 8PSK)
• Responses received from several manufacturers
  (General Dynamics, L-3 Communicaitons, Rockwell
  Corp, Northrup Grumann)
• Cost to complete current General Dynamics BB
  design is on the order of 1M/1 year for a 600
  Mbps capability
• Space qualified Ka-band upconverters and
  TWTAs/SSPAs have been developed by several
  manufacturers
• Motorola, Lockheed Martin, Bosch, Thomson Tubes

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Candidate Ka-Band Ground Equipment Summary

• 5-Meter S/Ka-Band Antenna (including LNA) 1.5M
• Ka-Band Downconverter 80K
• Low-Rate Receiver (up to 10 Mbps) 140K
• High-Rate Receiver (600 Mbps) 0.9-1.0M
• Data Storage System 750K
• Monitor and Control System 225K
• Facilities and Installation 500K
• Project Mgmt., Sys. Engineering,
  Test/Verification 500K
• Contingency 250K
• Total Ka-band ground terminal equipment site

NOTE Hardware costs are rough estimates and
assume the implementation of a single antenna,
and prime and redundant equipment chains.
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Summary

• The goals for future near-earth science missions
  include
• Higher data rates (up to 1 Gbps) for
  space-to-ground
• Minimize data latency
• Lower cost communications subsystems with reduced
  size and weight
• X-band resources are available today, but
• Band is becoming congested
• Spectrum pressures to limit mission bandwidths
  may prove extremely difficult to meet future
  wideband downlink requirements
• Ka-band will meet future wideband downlink
  requirements
• Ka-band infrastructure is available through the
  NASA TDRS (F8 operational)
• Ka-band technology developments show that Ka GN
  is a viable solution

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Back-Up Slides
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Recent Spectrum Issues

• The following spectrum management actions must be
  considered in the design of future missions
• SFCG is considering the channelization of the
  X-band Earth Exploration Satellite Service (EESS)
  allocation to facilitate band sharing among
  increasing number of missions. Also, SFCG is
  considering an upper limit on bandwidth
  utilization by any single mission for both S- and
  X-bands.
• International space standards organizations have
  developed bandwidth efficient modulation
  recommendations for S-band and X-band
• NTIA defines a spectral mask for all space
  services operating above about 1 GHz

22
NASAs Ka-Band Transition Product

• The Ka-Band Transition Project (KaTP) was
  initiated by NASA/GSFC in the fall of 1999 as a
  first step in transitioning the SN and GN to
  Ka-band operations
• The KaTP is a technology development,
  integration, and demonstration initiative to
  facilitate the transition of SN and GN users to
  allocated Ka-band frequencies
• Develop a new SN IF service using the TDRS H,I,J
  650 MHz channel
• Develop a GN demonstration system to demonstrate
  GN Ka-band operations and provide for future
  commercialization
• Provide a test bed within the SN and GN to
  demonstrate new communications technologies
• bandwidth efficient modulations
• high data rate receivers
• data processing/storage devices
• Provide the impetus and confidence to flight and
  ground system customers by demonstrating
  candidate Ka-band solutions

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KaTP Overview

• Space Network Segment
• Upgrade the SN ground stations at WSC and modify
  NCC software to take advantage of the new TDRS
  H,I,J spacecrafts 650 MHz Ka-band space-to-space
  return link in the 25.25 GHz to 27.5 GHz band
• Provide an IF output compatible with the GN
  implementation
• Frequency support capability in accordance with
  SNIP agreements
• Ground Network Segment
• Implement a demonstration ground terminal for the
  GN at Wallops Flight Facility to support
  direct-to-ground links in the 25.5 GHz to 27 GHz
  band
• Provide an IF output compatible with the SN
  implementation
• S-Band support for command and health/safety
  telemetry

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Ka-Band Transition ProjectHigh Data Rate
Demonstrations

• KaTP high data rate demonstration will utilize
  the new equipment implemented within the SN and
  the new ground station implemented within the GN
  to
• Characterize the performance of the physical
  return links at rates up to at least 600 Mbps
• GN Direct-to-earth Ka-band downlink
• SN return Ka-band link relayed via TDRS H
• Characterize the acquisition and tracking
  performance of the GN Ka-band antenna
• Assess the effects of hardware distortion on the
  overall link
• Characterize the GN and SN system designs
• Provide an end-to-end system (i.e., reference
  link or test system) to help characterize new
  high rate Ka-band hardware.
• The demonstrations will assess the RF link
  performance via measurements of bit error rate
  and the signal spectra
• SN demonstrations are currently scheduled for the
  September 2002 timeframe

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Ka-Band Link Budget
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Ka-Band Ground Terminal - Reference Architecture
(S- Ka-Band)
LEO Spacecraft
NASA 4th Generation Transponder
Baseband
Ku-Band
Ka-Band
Data To/From
S-Band
Bandpass
Up
Amplifier
Up
Spacecraft
Transponder
Filter
Converter
Converter
Processor
Diplexer
Spacecraft Command
Ka-Band
S-Band
Housekeeping
Phased Array

Antenna
S/Ka-Band Antenna Assembly
Telemetry
Antenna
Nominal 5 Meter Antenna
High Rate
Science Data
Antenna
Control
Unit
S-Band
LNA and

Diplexer
switches
S-Band Equipment
Ka-Band Equipment
Common Time
Ka
-Band
Telemetry
S-band
ExistingCommercialSite
and Frequency
Ant. Angle Data
Downconverter
Downconverter
HPA
from Antenna Ctrl Unit
Standard
IF Switch
Telemetry
S-band
Tracking
Receiver

Exciter
Processor
High Rate

Low Rate

Equipment
Demodulator
Demodulator
Bit
Bit
Monitor and
Synchronizer
Synchronizer
Command
Control

Data Switch
Modulator
Decoder
Decoder
Subsystem
Tlm/Cmd

Telemetry
Baseband
RAIDData Storage
Data Switch
Data Storage
Processor
Cmd Data
Science Data to Customer MOCs/PIs
Status and Scheduling Data
Tlm Data
Tracking Data
Ground Station Data
Telecommunications Interface
To/From Leased

- future capability
Telecomm Service
27
AGS 11 Meter Antenna Load
Missions Supported Aqua Aura EO-1 IceSAT Landsa
t-7 QuikSCAT TRACE
8/1/01 1/1/02
6/1/02 1/1/03 6/1/03
1/1/04
6/1/04 1/1/05
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SGS 11 Meter Antenna Load
Missions Supported Aqua Aura EO-1 IceSAT Landsa
t-7 QuikSCAT
8/1/01 1/1/02
6/1/02 1/1/03 6/1/03
1/1/04
6/1/04 1/1/05