Some general characteristics of the Deep Space Network are described and related to services needed by a manned mission to Mars. Specific details of the current Network capabilities and those planned for the near future may be found in the reference

Layland, James W.

Reid, Macgregor S.

Ruskin, Arnold M.

English

NASA Technical Reports Server

N87-17792
TELECOMMUNICATIONS AND RADIO-METRIC SUPPORT
FOR A MANNED MISSION TO MARS1
Arnold M. Ruskin, James W. Layland, and Macgregor S. Reid
Office of Telecommunications and Data Acquisition
Jet Propulsion Laboratory, California Institute of Technology
Pasadena, California
ABSTRACT
This paper describes some general characteristics of the Deep Space
Network and relates them to services needed by a manned mission to Mars.
Specific details of the Network's current capabilities and those planned
for the near future may be found in the reference.
DISCUSSION
NASA's Deep Space Network is a multimlsslon telecommunications and
radlo-metric facility used to support space science and exploration. The
Network is physically located on three continents, i.e. in southern Cali-
fornia, U.S.A.; near Madrid, Spain; and near Canberra, Australia, and
provides nearly complete coverage of deep space. It is designed and
managed overall by California Institute of Technology's Jet Propulsion
Laboratory (JPL), and its California facilities are installed and
operated by contractors to JPL. The Network's overseas facilities are
managed locally and operated by agencies of the Spanish and Australian
governments via internatlonal agreements.
The Network's basic services are telemetry reception, command trans-
mission, and radio-metric data (position and velocity) acquisition. The
ability to provide these services enables the Network also to perform
flight radio science, radio astronomy, very long baseline interferometry
(VLBI), geodynamics measurements, and searches for extraterrestrial In-
telligence (SETI). It's very stable radio-metric instruments have been
used to attempt gravitational wave detection, and its long-term radio-
metric measurements of the Viking Landers contributed to tests of general
reiatlvlty.
The Network transmits at frequencies of 2025 to 2120 MHz and
receives at frequencies of 1659 to 1675 MHz, 2200 to 2300 MHz, and 8400
to 8500 MHz. Transmission at 7145 to 7190 MHz will be provided for
1Thls work was performed by Jet Propulsion Laboratory, California
Institute of Technology; Pasadena, California; under contract to the
National Aeronautics and Space Administration.
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https://ntrs.nasa.gov/search.jsp?R=19870008359 2020-03-20T12:45:15+00:00Z
Project Galileo in 1987, and spectrum space has been allocated for deep
space communications in the vicinity of 32 GHz downlink and 34 6Hz
uplink. Space-based antennas, both microwave and optical, have been
considered from time to time and may become a reality in the 21st
century.
There are three or four antennas at each site, i.e. California,
Madrid, and Canberra. The most sensitive antenna system at each site can
receive data from Voyager-class spacecraft (20 Watts transmitter power
and 48.2 dB antenna gain at 8400 to 8500 MHz) at rates of 115.2 kbps from
Jupiter or 44.8 kbps from Saturn. The Network's other antenna systems
are also very sensitive. If, for example, a Mars mission has a 1.5-meter
directional antenna and a IO0-W transmitter operating within 8400 to 8500
MHz, the Network's regular 34-meter antenna system can simultaneously
receive digital voice communications (9.6 kbps), 16 kbps telemetry, and
16.4 kbps slow scan TV (8 seconds per black and white picture of 128 x
128 plxels). Three to four times this basic total amount of data can be
received using the Network's most sensitive antennas, and about five
times the basic amount can be received if antennas are arrayed.
Network transmitters operate at 20 kW to 100 kW, depending upon mis-
sion need. These transmitted power levels are up to 1028 times greater
than the received telemetry power level cited in the previous paragraph
and provide ample upllnk communications capability to an omnidirectional
antenna at Mars and substantial signal-to-noise ratios at Mars, thereby
enabling satisfactory radio-metric measurements. A transmitter capable
of 400 kW ls also available for emergency situations.
With present or currently planned equipment, the Network can process
downlink data at rates of 6 bps to 5 Mbps with an undetected bit error
rate of 1 part in 106 or less. The Network achieves a frequency sta-
bility of 7 parts In 1014, which enables radio-metric data precisions in
angle and angle rate of 50 nanoradtans and 5 ptcoradians per second, res-
pectively, and in range and range rate of 5 meters and 2 millimeters per
second, repectlvely. Together, these capabilities allow important
position and velocity measurements at Mars.
Beginning with its first antenna In 1958, the Network has been
managed as an evolving capability. New technologies have been planned as
potential needs appeared and then implemented as these needs were
834
confirmed. Equally important, Network research and development has often
Identlfled opportunities for new telecommunlcatlons or radio-metric
capabilities, which were implemented when user requirements arose. The
Network's objective has always been to offer the most capable and cost-
effective telecommunications and radio-metric service possible,
integrated over all Network users.
Current Network research and development and planning studies are
considering the following capabltttes: reception in selected frequency
bands over the entire range of 1 to 50 GHz, 500 NHz instantaneous band-
widths, communications coding techniques that will double llnk effl-
clencles, 1 part in 1017 frequency stability, and 5 nanoradlan radio
navigation by very long baseline tnterferometry (VLBI), as well as the
orblttng antennas mentioned above. These capabilities will be developed
whenever users require.
As indicated above, the Network's current technology can amply
support both the communications needs and the Interplanetary and local
navigation needs of a manned mission to Mars. New capabilities
installed to meet the requirements of future missions will extend that
ability before the turn of the century.
REFERENCE
DEEP SPACE NETWORK/FLIGHT PROJECT INTERFACE DESIGN
HANDBOOK, Vol. I, Existing DSN Capabllltles; Vol.
II, Proposed DSN Capabilities, Document 810-5, Rev.
D, Pasadena, California: Jet Propulsion Laboratory,
California Institute of Technology, 1984.
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Telecommunications and radio-metric support for a manned mission to Mars

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