Deep
Space
Network
SS
Spectrum Management Issues
Presentation to the NRC Committee
on Radio Frequencies [CORF]
May 14, 2003
by
Dr. Barry Geldzahler
NASA HQ
Program Executive for Space Operations
202-358-0512
[email protected]
160
SS
140
120
100
80
DSN Facilities
60
40
20
0
20
40
60
80
100
120
140
160
180
80
70
GOL DSTONE
JPL
Ne twork
Ope ration s
Co ntrol
Ce nter an d
CTA 21,
Pasad ena
DSS 25
60
MIL 71
DSN's Merr itt I s.
Launch Suppor t
Fac ility
50
MA DRID
40
CTT
30
DSS 26
9/02
34 -METER B EAM
WAVEG UIDE (BW G)
DSS54
DSS5 5 11/03
DSS 27
20
10
GPS
DSS 24
34 -METER B EAM
WAVEG UIDE (BW G )
GOL DSTONE
SPC
DSS 14
70 -METER
DSS 16
26 -METER
MA DRID
SPC
DSS 63
70 -METER
SPAIN
CALIF ORNIA
DSS 15
34-MET ER
HI-E FFIC IEN CY (HEF )
DSS 34
DSS 65
34 -METER
HI-EF FICIENC Y (H EF)
GP S
DSS 66
26 -METER
0
DSS 33
11-METER
10
34 -METER B EAM
WAVEG UIDE (BW G )
20
CAN BER RA
SPC
DSS 43
70 -METER
40
AUSTRALIA
DSS 53
11-METER
CANB ER RA 30
DSS 45
34 -METER
HI-EF FICIENC Y (H EF)
50
GP S
60
DSS 46
26 -METER
70
SS
•
The Army National Training Center expansion at Fort Irwin for large-scale desert
training.
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–
–
–
•
The Army has purchased more than 100,000 acres south/South West of Goldstone.
This area is directly in the direction where our antennas track spacecraft.
Army is planning to use several thousand troops, several hundred vehicle and many airplanes
and helicopters in that area all with state of the art communication gears.
With thousands of emitters, there is a significant potential for interference to Goldstone
antennas.
The interference of X-band EESS missions with X-band deep space missions. EESS
missions use the 8025-8400 MHz band and usually are very wide band (several hundred
MHz). The out of band emissions of EESS missions can fall within the 8400-8450 MHz
band of deep space missions.
–
•
High Level Spectrum Concerns
We need to have a NASA policy directing all NASA EESS missions to filter their out of band
emissions.
The third issue is JWST and its options and trade-offs in using X- or Ka-band.
–
This is an example of a bigger issue: what is the proper band for high data rate near-Earth
missions operating at L2.
SS
•
•
•
•
•
•
•
•
Other Spectrum Issues
S-Band TDRSS return link (2287.5 MHz center, 6 MHz bandwidth) - Users of this link
should implement filter on their satellites to reduce coordination load to project and
DSN.
X-Band uplink (7145-7190 MHz) - Approval of primary status (relative to the Fixed
Service) is expected at WRC2003.
S-Band uplink (2110-2120 MHz) - Restricted by IMT2000 at Madrid.
X-Band downlink (8400-8450) - Growing congestion. A provisional SFCG guideline
advocated moving high rate telemetry of deep space missions to the 32 GHz band.
MRO will be the first mission to do so. More stringent guidelines may be needed in the
future.
S-Band downlink (2290-2300 MHz) - Reduced mission requirement.
32 GHz downlink - Sharing with HDFS is being studied under ITU-R.
Mars relay links - SFCG established provisional frequency assignment guidelines
(SFCG 22-1).
Frequency assignment to new deep space missions - SFCG assigned study
responsibility to NASA/JPL - SFCG RES 21-1. More bandwidth requirement expected
in the future.
SS
Future of the DSN at
Radio Frequencies
• Loss of low frequencies [S-band]
• Move to higher frequencies [Ka- band]
SS
Outlook 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
[but this may change]
• Evolution toward more data-intensive instruments and
media
NASA missions are getting more ambitious and can
return more data than ever before.
SS
Data Rates of Today’s
Instrumentation Are A Small
Fraction of Tomorrow’s Deluge
Electromagnetic radiation carries only four kinds of information:
Amplitude
Phase
Frequency
Polarization
•
Today’s planetary studies to data generally tap only amplitude and
frequency.
•
Tomorrow’s planetary studies will include synthetic aperture radar,
interferometry, narrower channel hyperspectral imagers, polarimeters,
and ???
Data rates will reach unprecedented heights, and we must
begin preparations now to capture that data
Outlook for the current DSNRequirements
SS
e.g. Maximum Supportable Rates for a Mars Orbiter/Relay Circa 2005-2010
X-SAR
Magellan
Cassini
SAR
SAR
Synthetic Aperture Radar
SIR-C &
SRTM
(X-band)
SRTM
(C-band)
AIRSAR
Data for Science
Terra
ASTER (TIR)
“Adequate”
Science
Image/min*
(4bpp)
Cassini ISS
MGS MOC
Planetary Images
1E+04
“Adequate”
Public
Image/min*
(1bpp)
Data for Public
Direction of Increasing
Sense of Presence
1E+05
Cassini
VIMS
Landsats
12-Channel IMP
1,2, &3 MSS Pancam/min
Multi-Spectral & Hyper-Spectral Imagers
OrbView-2
“Quality”
Science
Image/min*
1E+06
MPEG-1
(352x240 at
30 frames/sec)
Anticipated maximum supportable
data rate (circa 2005-2010) for link
between Mars S/C 2.66 AU from Earth
with 100W TWTA and 5m HGA
and DSN:
34m at X-band
34m at Ka-band
70m at X-band
70m at Ka-band
Terra
12-Channel
AVIRIS
ASTER
IMP Pancam/min
(SWIR)
(3:1 compression)
NEMO,
Lansats
4&5 TM OrbView-4, EO-1 ALI
Landsat 7
Terra
ETM+
ASTER
(VNIR)
1E+07
Ave. MPEG-2 (704x480
at 30 frames/sec)
Video
ATV Standard
(Min.)
ATV
Gen. Delivery
Standard
Rate(6MHz
(Max.)
Channel)
1E+08
Raw NTSC
Studio Quality
Video (720x486
at 30 frames/sec)
HDTV
IMAX
SS
Bringing Home the Bacon
Two Approaches:
• Radio Frequencies
• Optical Communications
SS
Radio Frequencies
• Three Pronged Approach:
– More Efficient Encoding of the Data on the Spacecraft
• We are pushing the theoretical limits of what can be accomplished in
coding technologies
– More powerful Transmitters and/or More Bandwidth on the Downlink
• We are deploying more powerful, larger bandwidth transmitters
– Larger Ground-based Collecting Area
• The Next Generation Deep Space Network
SS
Enabling NASA Science for the
Next 50 Years
The Next Generation DSN
• Increase DSN telemetry capability by a
factor of 10^6
• Provide radiometric observables for precise
spacecraft navigation
• Enhance DSN Science capabilities
Need
to
go
to
Ka
Band
SS
Figure 1. Spectral Occupancy of Mars Missions in 2007 Time Frame (Data rates are as currently conceived by missions)
0
Relative PSD, dB
-10
-20
-30
8400
8405
8410
8415
8420
8425
8430
8435
8440
8445
Frequency, MHz
-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
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)
8450
SS
Choose Your Limitation
Two Choices:
• Bandwidth Limited
• Signal/Noise Limited
SS
Spacecraft Radio Systems
Ka-Band TWTA
Critical Design Review of 35W TWTA was
delayed to accommodate needs of Mars `05
mission
„
„
Tube selected for flight on M`05
Expanded review will validate consistency
with flight requirements
Review held at contractor facilities
„
„
Output
Input
Collector
TWT: Thales (Thomson) in Velizy, France
EPC: Tesat-Spacecom (Bosch SatCom) in
Baknang, Germany
Draft of review material has been received at
JPL -- under detail review
Contractor is continuing with TWTA
development as if CDR had been passed
All indications are that TWTA development and
performance are on track
Flight qualified model due to be delivered in
Aug 02
Code S is providing funding to MRO to fly the
Ka band Tx as a demo
Gun
Circuit,
Tube,
Helix
Ka-band 35W TWT
SSDSN Ka-band Downlink Readiness
Goldstone
•
•
•
Today: First operational DSN Ka-band 34m BWG
is already on-line
– Goldstone DSS 25 supported ‘98 DS1 Ka demo
– Now supporting Cassini Radio Science
Experiment
By MRO arrival (2006): One add’l 34m BWG w/
Ka-band capability at each complex
– DSS 26 at Goldstone
– DSS 55 (new BWG) at Madrid
– DSS 34 (upgrade) at Canberra
Alternate Assets [IACG WG4]:
– 34m ESA dish at New Norcia, Australia
– 49m equivalent dish at Narrabri, Australia
– 34m dish at Cebreros, Spain [tied to Venus
Express]
Madrid
Canberra
2001
25
2006
25
26
55
New Norcia
34 Narrabri
2008
25
26 24
34
55 54 ESA
New Norcia 34 Narrabri
DSN Ka-band Implementation Plan
SS
DSN Array: Working Baseline
• 400 12-m antennas at each of the three DSN
longitudes [equivalent of a 240m antenna]
– Freq range 2-44 GHz
– Primary use X [8GHz] and Ka [32 GHz for
Deep Space]
– The future in the radio is Ka band
Capturing High Rate Data
SS
Maximum Data Rate vs Distance
With 5kW DC at Spacecraft
1.E+11
Optical 2010
Data Rate, Bits/Second
1.E+10
1.E+09 360 x12m Ka
3600 x 12m Ka
To capture these high data
rates, need 500 MHz
bandwidth of the deep
space spectrum.
1.E+08
1.E+07
1.E+06
70m X
or 34m Ka
1.E+05
1.E+04
0.01
MARS
0.1
Distance, A.U.
1
JUPITER
10
We’re looking for
additional Ka band
bandwidth to enable a
higher science return