3 5 deep space communications
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SSOutlook for the DSN- Preparing
for an Exciting Future
DRIVERS
Growth of proximity links and consequent bandwidth demand on
trunk-lines
Migration of Space Science Enterprise mission set into deep space
Mission plan reliance on large aperture ground stations
Evolution toward more data-intensive instruments and media
NASA missions are getting more ambitious and can
return more data than ever before.
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SS8-Year View: Downlink Trends
Spacecraft Data Storage Capacity as a Function ofTime
0.0
0.11.0
10.0
100.0
1,000.0
10,000.0
2003 2007 2011GbitsofOnb
oardDataStorage
Minimum
Average
Maximum
*RadioAstron, MTO, and JIMO not included.
* Near-Earth Downlink Data Rates as a Function ofTime
0.1
1.010.0
100.0
1,000.0
10,000.0
100,000.0
2003 2007 2011DownlinkDataRate(kbps)
Minimum
Average
Maximum
*
*Excludes RadioAstron.
Spacecraft data storage trends suggest collected data
volumes will increase by 1-to-2 orders of magnitude.Near-Earth downlink rates also appear to be increasing1-to-2 orders of magnitude.
Project-Estimated Daily Data Volume as a Function
of Time
0.0
0.1
1.0
10.0
100.0
1,000.0
10,000.0
2003 2007 2011
Gbitsper
Day
Minimum
Average
Maximum
*RadioAstron, MTO, and JIMO not included.
*
Project-estimated daily data volumes also exhibit anincrease of 1-to-2 orders of magnitude.
Deep Space Downlink Data Rates as a Function of
Time
0.1
1.0
10.0
100.0
1,000.0
10,000.0
100,000.0
2003 2007 2011DownlinkDataR
ates(kbps)
Minimum
Average
Maximum
Deep space downlink rates are increasing by 1-to-2orders of magnitude as well.
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SSut oo or t e current -
Requirementse.g. Maximum Supportable Rates for a Mars Orbiter/Relay Circa 2005Maximum Supportable Rates for a Mars Orbiter/Relay Circa 2005--20102010
Synthetic Aperture Radar
Data for ScienceData for Science
Data for PublicData for Public
1E+04 1E+05 1E+06 1E+07 1E+08
Planetary Images
Video
Multi-Spectral & Hyper-Spectral Imagers
HDTV
NEMO,OrbView-4,Landsat 7
ETM+
EO-1 ALI
Anticipated maximum supportabledata rate (circa 2005-2010) for linkbetween Mars S/C 2.66 AU from Earth
with 100W TWTA and 5m HGAand DSN:
34m at X-band34m at Ka-band
70m at X-band70m at Ka-band
CassiniSAR
Terra
ASTER(VNIR)
SIR-C &SRTM
(X-band)
SRTM(C-band)
Direction of IncreasingData Richness
Direction of IncreasingSense of Presence
X-SARMagellan
SAR
MGS MOC
Cassini ISS
AVIRIS
AIRSAR
Lansats4&5 TM
Landsats1,2, &3 MSS
OrbView-2
CassiniVIMS
Terra
ASTER(SWIR)
TerraASTER (TIR)
IMAX
AdequateScience
Image/min*(4bpp)
AdequatePublic
Image/min*(1bpp)
Quality
ScienceImage/min*
MPEG-1
(352x240 at30 frames/sec)
Ave. MPEG-2 (704x480
at 30 frames/sec)
ATV Standard
(Min.)
ATVStandard
(Max.)
Gen. DeliveryRate(6MHz
Channel)
12-ChannelIMP Pancam/min
(3:1 compression)
12-Channel IMPPancam/min
DATARATES(bits/s)
Raw NTSC
Studio QualityVideo (720x486
at 30 frames/sec)
*Reference picture is 1024 x 1024 with 12 bit depth. Planetaryimage compression characterizations from A. Kiely and F. Pollara.
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SS Looking Toward the 20-Year Horizon: 2.7AU Mars Orbiter/Relay ScenarioSynthetic Aperture Radar
Data for ScienceData for Science
Data for PublicData for Public
1E+04 1E+05 1E+06 1E+07 1E+08
Planetary Images
Video
Multi-Spectral & Hyper-Spectral Imagers
HDTV
NEMO,OrbView-4,
Landsat 7ETM+
EO-1 ALI
Anticipated maximum supportabledata rate (circa 2013) for link
between Mars S/C 2.66 AU from Earthwith 100W TWTA and 5m HGA
and DSN:34m at Ka-band70m at Ka-band
CassiniSAR
TerraASTER
(VNIR)
SIR-C &
SRTM(X-band)
SRTM(C-band)
Direction of IncreasingData Richness
Direction of IncreasingSense of Presence
X-SARMagellan
SAR
Cassini ISS
AVIRIS
AIRSAR
Lansats4&5 TM
Landsats
1,2, &3 MSS
OrbView-2
CassiniVIMS
TerraASTER(SWIR)
Terra
ASTER (TIR)
IMAX
Adequate
ScienceImage/min*
(4bpp)
Adequate
PublicImage/min*
(1bpp)
Quality
ScienceImage/min*
6.8E+8 bps with200:1 compression
MPEG-1(352x240 at
30 frames/sec)
Ave. MPEG-2 (704x480at 30 frames/sec)
ATV Standard(Min.)
ATVStandard
(Max.)
Gen. Delivery
Rate(6MHzChannel)
12-ChannelIMP Pancam/min(3:1 compression)
12-Channel IMPPancam/min
MGS MOC
Maximum supportable optical comm data rate
at maximum Earth-Mars separation distanceassuming 10m optical telescope on ground &50cm telescope with 5W laser on S/C.
DATA
RATES(bits/s)
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SS Bringing Home the Bacon
NASAs Office of Space Science is exploring two approaches:1. Optical communications
2. Enhanced RF communications
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SS Optical Communication
Operational demonstration of laser comm on deep space missions will occuron the Mars Telcom Orbiter in 2009
Current design parameters:
Average laser power = 5W; 300W peak
Wavelength = 1.06 microns
Geiger Mode Avalanche Photodiodes
Target Data Rates from Mars: 3 Mbps at conjunction; 10 Mbps at opposition
Looking at beacon and beaconless pointing systems
Receive Terminals:
Ground-based: 3-9 8-10m class collecting area required [not imaging quality]
Could be accomplished with an array of 16 off the shelf telescopes or 8 1m
telescopes arrayed as well High altitude balloons
Space based data capture
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SS RF Communication
Three Pronged Approach:
More Efficient Encoding of the Data on the Spacecraft
More powerful Transmitters and/or More Bandwidth on the
Downlink
Bigger Light Bucket
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SS Moving Up- to Ka Band
Why Ka-band and Why Now?Deep space X-Band allocation is getting crowded
More missionsHigher telemetry rates:
Will affect spectrum availability to future missions
for many years to come
Only 50 MHz allocated. Will not increase.
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SS 2007 Mars Missions Spectra, Planned Rates
Figure 1. Spectral Occupancy of Mars Missions in 2007 Time Frame (Data rates are as currently conceived by miss ions)
-30
-20
-10
0
8400 8405 8410 8415 8420 8425 8430 8435 8440 8445 8450
Frequency, MHz
RelativeP
SD,
d
Odyssey(220ksps, ch.8)Mars07Landerr (7.2 ksps)Mars07Rover (7.2 ksps)Mars Scout Orbiter(9 ksps )ME(586 ksps, ch.18)CNES07Orbiter(60 ksps)Telesat( 360 ksps)Mars05( 4.4Msps, filtered)
-Only Mars Express and Odyssey have been
assigned a frequency channel
-The center frequency (downlink) of the n th
channel is given by
8400.06 + (n-3)*1.36 MHz
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SS 2007 Mars Missions Spectra, LinkSupportable Rates
Figure 2. Spectral Occupancy of Mars Missions in 2007 Time Frame (Data rates for Mars 05 Orbiter, CNES 07 Orbiter and Telesat
are maximum rates supportable at 0.6 AU range)
-30
-20
-10
0
8400 8405 8410 8415 8420 8425 8430 8435 8440 8445 8450
Frequency, MHz
Relative
PSD
,dB
Odyssey(220ksps, ch.8)Mars07Landerr (7.2 ksps)Mars07Rover (7.2 ksps)Mars Scout Orbiter(9 ksps)ME(586 ksps, ch.18)CNES Orbiter (1 Msps, QPSK)
Telesat(6.7 Msps, QPSK)Mars05(17.2 Msps, QPSK)
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SS Choose Your Limitation
Two Choices:
Bandwidth Limited
Signal/Noise Limited
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SSSpacecraft Radio Systems --
Ka-Band TWTA
Critical Design Review of 35W TWTA wasdelayed to accommodate needs of Mars `05mission Tube selected for flight on M`05 Expanded review will validate consistency
with flight requirements
Review held at contractor facilities TWT: Thales (Thomson) in Velizy, France
EPC: Tesat-Spacecom (Bosch SatCom) inBaknang, Germany
Draft of review material has been received atJPL -- under detail review
Contractor is continuing with TWTAdevelopment as if CDR had been passed
All indications are that TWTA development andperformance are on track
Flight qualified model delivered in Dec 02
Code S is providing funding to MRO to fly theKa band Tx as a demo
Ka-band 35W TWT
Output
Input
GunCollector
Circuit,
Tube,Helix
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SSEnabling NASA Science for the Next 50 Years
The Next Generation DSN
Increase DSN telemetry capability
Provide radiometric observables for precise spacecraftnavigation
Enhance DSN science capabilities
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SSOne Possible Approach:
Arrays of Small Antennas
Technology advances in a number of areas are making large arrays of smaller
antennas both feasible and affordable
Low cost, high performance parabolic antennas for satellite TV
Low cost, low noise, wide bandwidth LNAs
Low cost, reliable cryogenics
Low cost fiber optic communications
Faster computing
Large Arrays could add to the DSNs value to NASA by dramatically
increasing capabilities for spacecraft communications, navigation, and ground
based science
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SS Optimum Antenna Size
Cost of Providing G/T Equivalent of
12 34m Antennas or 100 12m Antennas
Site, Software,
Engineering
Electronics Antenna
0
100,000
200,000
300,000
400,000
6 8 10 12 18 25 34Antenna Diameter, Meters
TotalCost,$K
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SS Current Status of Array Studies
Design studies are underway leading to a cost review in early FY04
Reflector Manufacture
Site Selection
Overall Systems Design & Electronics
Uplink Study
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