There is a need to understand NASA s Deep Space Network (DSN) coverage gaps and any limitations to provide redundant communication coverage for future deep space missions, especially for manned missions to Moon and Mars. The DSN antennas are required to provide continuous communication coverage for deep space flights, interplanetary missions, and deep space scientific observations. The DSN consists of ground antennas located at three sites: Goldstone in USA, Canberra in Australia, and Madrid in Spain. These locations are not separated by the exactly 120 degrees and some DSN antennas are located in the bowl-shaped mountainous terrain to shield against radiofrequency interference resulting in a coverage gap in the southern hemisphere for the current DSN architecture. To analyze the extent of this gap and other coverage limitations, simulations of the DSN architecture were performed. In addition to the physical properties of the DSN assets, the simulation incorporated communication forward link calculations and azimuth/elevation masks that constrain the effects of terrain for each DSN antenna. Analysis of the simulation data was performed to create coverage profiles with the receiver settings at a deep space altitudes ranging from 2 million to 10 million km and a spherical grid resolution of 0.25 degrees with respect to longitude and latitude. With the results of these simulations, two- and three-dimensional representations of the area without communication coverage and area with coverage were developed, showing the size and shape of the communication coverage gap projected in space. Also, the significance of this communication coverage gap is analyzed from the simulation data

Fuentes, Michael

Kegege, Obadiah

Meyer, Nicholas

Sil, Amy

NASA Technical Reports Server

2012 IEEE Aerospace Conference,  Big Sky, Montana,  March 4-10, 2012. 
 
   U.S. Government work not protected by U.S. copyright 
 1 
Three-Dimensional Analysis of Deep Space Network 
Antenna Coverage 
Obadiah Kegege 
NASA Glenn Research Center 
21000 Brookpark Rd. 
Cleveland, OH 44135 
216-433-3127 
obadiah.o.kegege@nasa.gov 
Michael Fuentes 
QinetiQ North America. 
NASA Glenn Research Center 
21000 Brookpark Rd. 
Cleveland, OH 44135 
michael.a.fuentes@nasa.gov 
Nicholas Meyer, Amy Sil 
NASA Glenn Research Center 
21000 Brookpark Rd. 
Cleveland, OH 44135 
nicholas.e.meyer@nasa.gov, 
amy.a.sil@nasa.gov  
 
Abstract—There is a need to understand NASA’s Deep Space 
Network (DSN) coverage gaps and any limitations to provide 
redundant communication coverage for future deep space 
missions, especially for manned missions to Moon and Mars. 
The DSN antennas are required to provide continuous 
communication coverage for deep space flights, interplanetary 
missions, and deep space scientific observations. The DSN 
consists of ground antennas located at three sites: Goldstone in 
USA, Canberra in Australia, and Madrid in Spain. These 
locations are not separated by the exactly 120 degrees and 
some DSN antennas are located in the bowl-shaped 
mountainous terrain to shield against radiofrequency 
interference resulting in a coverage gap in the southern 
hemisphere for the current DSN architecture. To analyze the 
extent of this gap and other coverage limitations, simulations of 
the DSN architecture were performed. In addition to the 
physical properties of the DSN assets, the simulation 
incorporated communication forward link calculations and 
azimuth/elevation masks that constrain the effects of terrain 
for each DSN antenna. Analysis of the simulation data was 
performed to create coverage profiles with the receiver settings 
at a deep space altitudes ranging from 2 million to 10 million 
km and a spherical grid resolution of 0.25 degrees with respect 
to longitude and latitude. With the results of these simulations, 
two- and three-dimensional representations of the area without 
communication coverage and area with coverage were 
developed, showing the size and shape of the communication 
coverage gap projected in space. Also, the significance of this 
communication coverage gap is analyzed from the simulation 
data. 
TABLE OF CONTENTS 
1. INTRODUCTION ................................................. 1 
2. OVERVIEW OF THE PRESENT DSN ................... 1 
3. STUDY APPROACH AND MODEL    
PARAMETERS ........................................................ 2 
4. ANALYSIS OF DSCC TERRAIN AND AZ-EL 
MASKS .................................................................. 3 
5. DSN COMMUNICATION COVERAGE 
SIMULATION DATA ............................................... 4 
6. SUMMARY ......................................................... 8 
REFERENCES ......................................................... 8 
BIOGRAPHIES ........................................................ 8 
 
1. INTRODUCTION 
This paper presents the analysis of NASA’s Deep Space 
Network (DSN) communication coverage. In the history of 
space exploration, DSN antennas have provided 
communication coverage of spacecrafts and satellites from 
Geosynchronous Earth Orbit (GEO) to the edge of our solar 
system. Because of the location of DSN antennas, a 
communication coverage gap exists in the southern 
hemisphere. There is a need to understand this 
communication gap to assess the possible impact on current 
and future space missions. 
This communication coverage gap was analyzed using 
NASA’s Integrated SCaN (Space Communication and 
Navigation) Simulator. The SCaN model library was used to 
develop the physical attributes and constraints of the DSN 
architecture within the simulation. In the analysis, we 
created models of DSN antennas (as presented in section 3) 
and receiver models at various deep space altitudes ranging 
up to 10 million km. The simulations incorporated antenna 
parameters, forward link calculations, and the 
azimuth/elevation terrain masks to constrain the line of sight 
for each antenna. Also, the SCaN model library and Satellite 
Tool Kit (STK) were used to develop the simulations. 
From the results of the simulations, two-dimensional (2D) 
and three-dimensional (3D) profiles representing the DSN 
communication coverage are presented in this paper. Also, 
the profiles show the size, shape, and the percentage of the 
communication coverage gap projected in space at various 
deep space altitudes. 
2. OVERVIEW OF THE PRESENT DSN  
The DSN comprises three Deep Space Communications 
Complex (DSCC) facilities that are located in Goldstone, 
USA; Madrid, Spain; and Canberra, Australia. Each DSCC 
has one 70-m antenna, one 34-m high efficiency (HEF) 
antenna, at least one 34-m beam wave guide (BWG) 
antenna, and a signal processing center [1]. Also, the DSN 
has test facilities that support compatibility testing (Figure 
1): Development Test Facility (DTF-21) that conducts tests 
of radiofrequency (RF) compatibility between the DSN and 
the customer’s flight system, Merritt Island Launch (MIL-
71) support facility that provides DSN-compatible support
https://ntrs.nasa.gov/search.jsp?R=20120004035 2019-08-30T19:49:42+00:00Z
  2 
 
Figure 1.  Overview of DSN 
for launch operations, and a transportable Compatibility 
Test Trailer (CTT-22) that conducts RF compatibility tests 
between the DSN and the customer's flight system at the 
customer's facility [1]. 
3. STUDY APPROACH AND MODEL PARAMETERS 
Figure 1 shows the 13 antennas that are currently operated 
by DSN.  Each of these antennas was modeled as a 
transmitter. To perform forward link calculations, receivers 
were modeled at various deep space altitudes (simulated up 
to 10 million km). For each DSN antenna, we used the 
specific antenna parameters and terrain data to define the 
simulation scenarios. These parameters include the position 
using the Cartesian coordinates of DSN antennas in the 
ITRF93 reference system [2], antenna size and shape, 
frequency bands, polarization, transmitting power, operating 
azimuth/elevation (Az/El) angles, half-power beamwidth, 
and main-lobe gain [3], [4], [5], and [6]. 
Other parameters such as the effective isotropic radiated 
power (EIRP) are calculated in the simulations. The 
effective isotropic radiated power is given as: 
tt GP +=EIRP                                     (1) 
where tP  is the power of the transmitting antenna and tG  is 
the gain of the transmitting antenna. At deep space receiver 
grid points, the received power is approximated by 
rpr GLP +−= EIRP , and can be rewritten as: 
)log(20
4
log20EIRP R
f
cGP rr −





++=
π
 (2) 
where 






−=
f
cRLp π4
log20)log(20  is the propagation path 
loss, R  is the distance between transmitter and receiver, 
rG  is the gain of the receiver, c  is the speed of light, and 
f  is the frequency. 
Table 1.  Example of parameters used in the models 
 Canberra DSS 34 
X-Band Transmitter Goldstone DSS 14 X-Band Transmitter 
Position 
(m) 
X = -4461146.756 
Y = +2682439.293 
Z = -3674393.542 
X = -2353621.251 
Y = -4641341.542 
Z = +3677052.370 
Frequency 
(GHz) 7.145 7.145 
Antenna type Parabolic Reflector Parabolic Reflector 
Polarization RCP/LCP RCP/LCP 
Diameter (m) 34 70 
Elevation 
angle (deg) 
Min: 5.923 
Max: 89.577 
Min: 5.962 
Max: 89.538 
Power  (W) 20,000 20,000 
Gain  (dBi) 68.3 74.5 
 
  3 
The transmit parameters (as expressed in Table 1) for each 
antenna were incorporated into the simulation scenario. The 
minimum and maximum elevation angles in Table 1 define 
the mechanical limits of the antenna. The line-of-sight of 
each antenna, which affects the overall coverage, is also 
affected by the surrounding terrain. Given the line-of-sight 
characteristics, a given area in space may have redundant 
coverage from two or three DSCC antennas.   
4. ANALYSIS OF DSCC TERRAIN AND AZ-EL 
MASKS  
Figure 2 shows the terrain for Canberra Deep Space 
Communications Complex (CDSCC), Goldstone Deep 
Space Communications Complex (GDSCC), Madrid Deep 
Space Communications Complex (MDSCC), and the Az-El 
mask for each DSCC.    
 
 
Figure 2.  DSN terrain and Az-El masks for each DSCC 
 
 
Figure 3.  Terrain for each Deep Space Station (DSS) antenna at Goldstone DSCC
-2 
0 
2 
4 
6 
8 
10 
12 
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 
El
ev
at
io
n 
(m
) 
Azimuth (Deg) 
 Goldstone DSCC Azimuth vs. Elevation Terrain Masks 
DSS 14  
Elevation 
DSS 15  
Elevation 
DSS 24  
Elevation 
DSS 25  
Elevation 
DSS 26  
Elevation 
DSS 27  
Elevation 
  4 
The terrain for GDSCC has a resolution of 1/9 arc-second 
(~3 m), where as CDSCC and MDSCC have 1 arc-second 
(~30 m) resolution of terrain data. Using this terrain data, 
the Az-El masks shown in Figure 2 were computed (i.e., in 
Figure 3 for GDSCC). Each Deep Space Station (DSS) 
antenna’s line of sight is evaluated against the terrain during 
visibility computations (Figure 3). These masks serve to 
model the physical obstruction of the area surrounding the 
antennas, which is necessary for determining the 
communication coverage gap. 
 
5. DSN COMMUNICATION COVERAGE 
SIMULATION DATA 
Several simulations were performed using Satellite Took Kit 
(STK) and other tools. Data from these computations were 
used to create 2D and 3D communication coverage profiles 
with the receiver settings at deep space altitudes ranging up 
to 10 million km with a spherical grid resolution of 0.25 
degrees with respect to longitude and latitude. The coverage 
area of each individual antenna is generated and merged to 
produce the global coverage provided by the DSN at that 
various altitudes. Figures 4 (a) and (b) show 3D 
communication coverage profile, representing the size and 
shape of the gap projected in space. The area shown in pink 
(Figure 4) has communication coverage from at least one 
DSN antenna. The area shown in black is the 
communication coverage gap.  
Figure 5, 6, 7, and 8 show 2D coverage profiles projected up 
to altitudes of 40,000 km, 400,000 km, 4 million km, and 10 
million km. These profiles show the projection of the 
combined coverage on the Earth’s surface. A comparison of 
the 2D projections of the coverage gap for altitudes of 
40,000 km (Figure 5) and 400,000 km (Figure 6) show that 
the communication coverage gap decreases with increase in 
altitude. However, a comparison of the altitudes at 
4,000,000 km (Figure 7) and 10,000,000 km (Figure 8) 
show little change. The exponential decay of this gap with 
altitude is analyzed in section 5. 
 
 
 
  
Figure 4.   3D profiles of DSN communication coverage 
  5 
 
 
Figure 5.  2D profile of DSN communication coverage at altitude of 40,000 km 
 
 
 
 
Figure 6.   2D profile of DSN communication coverage at altitude of 400,000 km 
 
 
DSN communication 
coverage gap 
DSN communication 
coverage gap 
  6 
 
Figure 7.   2D profile of DSN communication coverage at altitude of 4,000,000 km 
 
 
 
Figure 8.  2D profile of DSN communication coverage at altitude of 10,000,000 km 
 
Figure 9 graphically shows the relationship between the 
percentage of the area with DSN communication and 
altitude of the corresponding receiver. The altitudes range 
from 2 million (distance from the Earth’s surface where 
deep space begins [7]) to 10 million km (maximum value 
allowed by the simulation software). By looking at the DSN 
coverage gap in Figures 4, 5, 6, 7, and 8; then comparing 
with the plot in Figure 9, we can see that coverage area 
increases rapidly then increases at a slower pace. This is a 
logarithmic function that can be predicted to have a very 
minimal increase after 10 million km. From analyzing the 
data in Figure 9, a function representing the percentage of 
the current DSN coverage at altitudes of greater than 2 
million km can be approximated as: 
% coverageDSN 99.078 ln( -1) m R= +   (3) 
DSN communication 
coverage gap 
DSN communication 
coverage gap 
  7 
where R (greater or equal to 2) is the altitude (in millions of 
km) and m is a function of the altitude and other parameters 
discussed in sections 3 and 4. 
 
Figure 9.   Percentage of DSN communication coverage 
by altitude 
Using Equation 3 to solve a system of equations for the data 
points in Figure 9, an equation representing the percentage 
of the current DSN communication coverage for altitudes of 
greater than 2 million km was derived as: 
 )1(ln
21.9
1215.0391.0078.99DSN coverage% −




 +
+= R
R
R  (4) 
whereby m that was introduced in equation 3 is: 





 +
=
R
Rm
21.9
1215.0391.0  
 
Figure 10.  Percentage of DSN communication coverage 
gap by altitude 
At an altitude of 17 billion km, more than twice Pluto’s 
farthest (7.5 billion km) orbiting altitude from Earth, the 
calculations show that DSN will have a coverage gap of  
~0.793% (Figure 10).   The formulation in Equation 4 is 
limited to the current DSN antenna parameters and terrain 
data.   
The full impact of the coverage gap cannot be assessed with 
static 2D analyses. The rotation of the Earth impacts where 
in space the gap is pointing. The location of the DSN gap 
can be formulated as in Figure 11.   From Figure 11, we can 
see that the circumference of the Earth at the equator RC  
can be approximated as: 
m.6940,075,016m 6,378,1372 =××= πRC   (5) 
 
Figure 11.  DSN gap and relative speed of Earth’s 
rotation 
The period of rotation of the Earth is 23 hours, 56 minutes, 
4 seconds (86,164 s). The Earth’s rotational velocity at the 
equator is: 
m/s1.465
s 86,164
m.6940,075,016
==RV               (6) 
Since ( )( ) = /2 cos (47 ) cos (47 )Rr C Rπ ° = ° , at a point on the 
DSN coverage gap, this rotational speed can be 
approximated by multiplying the speed at the equator by the 
cosine of the angle where the DSN communication gap 
falls. 
m/s2.317)47cos(m/s1.465 =°×=rV   (7) 
99.078 
99.096 
99.104 
99.108 
99.111 
99.113 
99.114 
99.115 
99.116 
99.075 
99.080 
99.085 
99.090 
99.095 
99.100 
99.105 
99.110 
99.115 
99.120 
2 3 4 5 6 7 8 9 10 
P
er
ce
nt
ag
e 
of
 D
S
N
 c
om
m
un
ic
at
io
n 
co
ve
ra
ge
 
Altitude from the Earth's surface (millions of km) 
Percent  of DSN Communication Coverage vs 
Altitude 
2000 4000 6000 8000 10000 12000 14000 16000
0.8
0.82
0.84
0.86
0.88
0.9
0.92
X: 399
Y: 0.8424
X: 1.7e+004
Y: 0.7935
Altitude from the Earth's surface (millions of km)
P
er
ce
nt
ag
e 
of
 D
S
N
 C
om
m
. C
ov
er
ag
e 
G
ap
Percentage of  DSN Communication Coverage Gap vs Altitude
X: 7500
Y: 0.8042
399 million km -
Mars' farthest
altitude from
Earth 7.5 billion km -
Pluto's farthest
altitude from
Earth
  8 
At an altitude of 10,000,000 km, this gap stretches from the 
longitude of about –75° to 2° (Figure 8). As the Earth 
rotates with the DSN communication gap rotating at 317.2 
m/s, a space mission within this DSN communication 
coverage gap will be without coverage for a maximum of:  
77 86164s 18430s 5.12hr
360
°
× = =
°
     (8) 
We have seen that, at an altitude of 10,000,000 km, a 
mission can be without coverage for up to 5.12 hours if it 
falls in the DSN coverage gap. This phenomenon is 
demonstrated in Figure 12. 
 
 
Figure 12.  3D simulation of DSN communication 
coverage gap projected in space 
The planetary bodies in the Solar System lie near the 
ecliptic plane. The ecliptic plane is tilted 23.5° with respect 
to the Earth’s celestial equator plane since the Earth’s 
rotational axis is tilted 23.5° because of this none of the 
eight solar system planets fall within this DSN coverage 
gap. Pluto (dwarf planet) is inclined ~ 17° relative to the 
ecliptic plane but does not get in the DSN coverage gap.  
 
 
6. SUMMARY  
In this study, we have modeled the DSN antenna parameters 
and communication link, and incorporated the terrain 
constraints to evaluate the communication coverage gaps 
within the DSN. In addition to each of the DSN antenna’s 
mechanical constraints and radiation pattern, terrain data 
was incorporated to model the communication coverage gap 
within DSN. From the simulation data, we have presented 
both 2D and 3D communication coverage profiles showing 
the location, size, and shape of this communication 
coverage gap projected in space at various deep space 
altitudes. 
The deep space antennas are required to provide coverage of 
deep space missions throughout the solar system. Though 
our simulations were limited to an altitude of 10,000,000 
km, a formula was derived that modeled the percentage of 
the current DSN coverage for deep space altitudes of greater 
than 10,000,000 km.  This analysis was based on the 
parameters of the current DSN assets.   The analysis can be 
used to assess the amount of time a mission can be without 
communication coverage at any altitude if it falls within this 
DSN gap. However, none of the current missions fall within 
the DSN communication coverage gap. This study did not 
include all celestial bodies in the solar system or outside the 
solar system.  Therefore, authors recommend analyzing the 
trajectories of Potentially Hazardous Asteroids (PHAs) to 
assess the capabilities of DSN antennas supporting a PHA 
mission. 
 
REFERENCES  
[1] JPL/NASA, “Deep Space Network Services Catalog,” 
DSN No. 820-100, Rev. E, Issued December 17, 2009. 
[2] JPL, “Cartesian coordinates of DSN antennas in the 
ITRF93 reference system (International Terrestrial 
Reference Frame),”  http://dsnra.jpl.nasa.gov/Antennas/ 
Antennas.html 
[3] JPL/NASA, “34-m and 70-m Command,” DSN No. 
205, Rev. C, Released June 1, 2010. 
[4] JPL/NASA, “34-m BWG Antennas Telecommuni- 
cations Interfaces,” DSN No. 104, Rev. F, Released 
June 1, 2010. 
[5] JPL/NASA, “34-m HEF Subnet Telecommunications 
Interfaces,” DSN No. 103, Rev. B, September 19, 2008. 
[6] JPL/NASA, “70-m Subnet Telecommunications 
Interfaces,” DSN No. 101, Rev. D, April 21, 2011. 
[7] JPL/NASA, “Frequency and Channel Assignments,” 
DSN No. 201, Rev. B, December 15, 2009. 
 
BIOGRAPHIES 
Obadiah Kegege is an Electronics 
Engineer in the Systems Definition and 
Communications Branch at NASA 
Glenn Research Center. He is part of 
the Space Communications and 
Navigation (SCaN) team. He received 
his BS in Control and Instrumentation 
Electronics Design from the University of Houston, MS in 
Electrical Engineering from the University of Texas Pan 
American, and a PhD from the University of Arkansas. 
 
Michael Fuentes is a Space 
Communication Network Architect 
and private consultant at the NASA 
Glenn Research Center, where he is 
responsible for the modeling and 
simulation of space communication 
networks and systems. Prior to NASA, 
Michael worked at Custom Computer 
Services developing custom business software for produce 
and environmental regulations companies. Michael holds 
a Master’s degree in computer engineering from Case 
  9 
Western Reserve University and a Bachelor’s degree in 
computer engineering from California State University, 
Fresno. 
 
Nicholas Meyer is pursuing a B.S.E. in 
Computer Science at the University of 
Pennsylvania. He worked as an intern 
with the SCaN Summer Intern Program 
at the Glenn Research Center during 
the summer of 2011.  
 
 
 
Amy Sil studying B.M.E at the 
University of Findlay. She worked as 
an intern with the SCaN Summer 
Intern Program at the Glenn Research 
Center during the summer of 2011.  
 
 
 


Three-Dimensional Analysis of Deep Space Network Antenna Coverage

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