Attachment Technical Annex SAT-LOI-20130315-00031

Attachment Technical Annex

This document pretains to SAT-LOI-20130315-00031 for Letter of Intent on a Satellite Space Stations filing.

IBFS_SATLOI2013031500031_989955

ATTACHMENT A
Technical Information to Supplement Schedule S

A.1 SCOPE AND PURPOSE

The purpose of this Attachment is to provide the Commission with the technical characteristics of
the VIASAT-3 satellite. This attachment contains the information required by 47 C.F.R. §25.114
and other sections of the FCC’s Part 25 rules that cannot be entered into the Schedule S
submission.

A.2 GENERAL DESCRIPTION

The VIASAT-3 satellite will operate at the nominal 79° W.L. orbital location and will provide
Ka-band services to parts of CONUS, Canada and Mexico. ViaSat proposes to offset the
satellite by 0.3° from 79º W.L. and to center the station-keeping box at 79.3° W.L. in part to
avoid any possibility of station-keeping overlap with the planned DIRECTV KU-79W satellite
that will operate at 79° W.L., but also in order to create a two-degree separation from a
Commission-authorized Ka-band satellite at 77.3° W.L.

The VIASAT-3 satellite will operate in the 28.1-29.1 GHz and 29.5-30.0 GHz bands (Earth-to-
space) and the 18.3-19.3 GHz and 19.7-20.2 GHz bands (space-to-Earth). The satellite network
will provide service to small user antennas. In addition, a limited number of larger gateway-type
antennas will be employed. The gateway-type antennas will have the capability of transmitting
in any channel within the 28.1-29.1 GHz and 29.5-30.0 GHz bands. Uplink transmissions from
the smaller user terminals will occur in the 28.35-29.1 GHz and 29.5-30.0 GHz bands.

The satellite will use a bent-pipe architecture with asymmetric forward (gateway-to-subscriber)
and return (subscriber-to-gateway) links. Forward links will consist of a single TDM 500 MHz
wide carrier (416.67 Msym/s), while the return links will use MF-TDMA with a variety of

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bandwidths/data rates employed. The network will use adaptive coding and modulation to
combat rain fades. That is, the modulation type, amount of coding and/or user data rate will be
dynamically varied to meet the link requirements during rain events (in addition to employing
uplink power control). The forward links will vary between 16-APSK, 8PSK and QPSK
modulations, depending on the amount of rain fade, while the return links will use 8PSK, QPSK
and BPSK modulation schemes.

A.3 SPACE STATION TRANSMIT AND RECEIVE CAPABILITY

The VIASAT-3 satellite’s beam coverage, both transmit and receive, will consist of 20 beams
serving antennas that link to the Internet/PSTN and/or provide TT&C or other system operation
functions (“A-Type Spot Beams”) and 72 beams that will be used principally to provide service
to end users (“B-Type Spot Beams”). For the A-Type Spot Beams, the peak downlink EIRP
varies between 56.9 dBW and 62.2 dBW, while the peak G/T varies between 17.1 dB/K and 21.9
dB/K. For the B-Type Spot Beams, the peak downlink EIRP varies between 62.7 dBW and 67.0
dBW, while the peak G/T varies between 18.2 dB/K and 22.7 dB/K.

The satellite’s antenna gain contours for the receive and transmit beams, as required by
§25.114(d)(3), are given in GXT format. However, because of the large number of beams
involved and the known problems of the Schedule S software in handling a large number of
beams, the GXT files have not been embedded in the Schedule S software file and are being
provided separately to the Commission.

A.4 FREQUENCY AND POLARIZATION PLAN

The VIASAT-3 satellite’s frequency plan for normal operating mode is given in Table A.4-1,
indicating channel center, polarization and bandwidth. Circular polarization is used on both the
uplink and downlink with the downlink polarization being orthogonal to the uplink polarization.
The satellite will employ a four-frequency re-use pattern such that any channel is re-used multiple
times by a combination of polarization and spatial isolation. This satisfies the requirements of
§25.210(d) of the Rules.
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Table A.4-1. Frequency Plan (Normal Mode)
Uplink Center Downlink Center
Bandwidth
Frequency Polarization Frequency Polarization
(MHz)
(MHz) (MHz)
28600 RHCP, LHCP 18800 LHCP, RHCP 1000
29750 RHCP, LHCP 19950 LHCP, RHCP 500

As explained in section A.11, the 1000 MHz channel, which supports two 500 MHz carriers, will
be reduced to a single 500 MHz channel (supporting one 500 MHz carrier) in the event that there
is a need to cease operating in a portion of the assigned spectrum to protect an NGSO network.
During the short period of time that the reduced bandwidth mode is in use, the frequency plan is
represented by Table A.4-2.

Table A.4-2. Frequency Plan (Reduced Bandwidth Mode)
Uplink Center Downlink Center
Bandwidth
Frequency Polarization Frequency Polarization
(MHz)
(MHz) (MHz)
28350 RHCP, LHCP 18550 LHCP, RHCP 500
29750 RHCP, LHCP 19950 LHCP, RHCP 500

For purposes of clarity, the transponder bandwidth configuration represented in the Schedule S is
for normal mode configuration reflected in Table A.4-1 above.

A.5 SERVICES TO BE PROVIDED

The VIASAT-3 satellite will be capable of providing a variety of FSS services, including
broadband access. Representative link budgets, which include details of the transmission
characteristics, performance objectives and earth station characteristics, are provided in the
associated Schedule S submission.

A.6 TT&C CHARACTERISTICS

The information provided in this section complements that provided in the associated Schedule S
submission.

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A.8 POWER FLUX DENSITY AT THE EARTH’S SURFACE

§25.208(c) contains PFD limits that apply in the 18.3-18.8 GHz band. The PFD limits of
§25.208(c) are as follows:

• -115 dB(W/m2) in any 1 MHz band for angles of arrival between 0 and 5 degrees above the
horizontal plane;
• -115+(δ-5)/2 dB(W/m2) in any 1 MHz band for angles of arrival δ (in degrees) between 5
and 25 degrees above the horizontal plane; and
• -105 dB(W/m2) in any 1 MHz band for angles of arrival between 25 and 90 degrees above
the horizontal plane.

In addition, §25.208(d) contains PFD limits that apply in the 18.6-18.8 GHz band produced by
emissions from a space station under assumed free-space propagation conditions as follows:

• -95 dB(W/m2) for all angles of arrival. This limit may be exceeded by up to 3 dB for no
more than 5% of the time.

§25.208 does not contain any PFD limits that apply in the 18.8-19.3 GHz band for GSO satellite
networks, however it is noted that Article 21 of the ITU Radio Regulations does include PFD
limits applicable to GSO satellites using the 18.8-19.3 GHz band. The ITU limits are identical to
those in §25.208(c).

Compliance with the applicable FCC and ITU PFD limits is demonstrated below using a simple
worst-case methodology. The maximum downlink EIRP that the VIASAT-3 satellite can transmit
is 67 dBW in 500 MHz. The shortest distance from the satellite to the Earth is 35,786 km,
corresponding to a spreading loss of 162.06 dB. Therefore the maximum possible PFD at the
Earth’s surface could not exceed -95.1 dBW/m2 in this 500 MHz (i.e., 67 -162.06). When the
system is operating in normal mode (i.e., using a 1000 MHz channel in the 18.3-19.3 GHz and
28.1-29.1 GHz frequencies), the two 500 MHz carriers within the 1000 MHz channel will each
meet the PFD performance described here. Allowing for the use of digital modulation with an
almost flat spectrum, the corresponding maximum PFD at an elevation angle of 90° measured in a
1 MHz band would not exceed -122.1 dBW/m2. The -122.1 dBW/m2/MHz level is less than the -

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115 dBW/m2/MHz PFD limit value that applies at elevation angles of 5° and below. Therefore,
compliance with the PFD limits is assured.

In addition, §25.208(d) provides an additional aggregate PFD limit in the 200 MHz wide band
18.6-18.8 GHz of -95 dBW/m2. In the worst case, this would correspond to a PFD limit of -118
dBW/m2/MHz (i.e., -95-10*log(200)). As demonstrated in the previous paragraph, downlink
transmissions from the VIASAT-3 satellite cannot exceed -122.1 dBW/m2/MHz at any angle of
arrival and therefore compliance with §25.208(d) is also assured.

A.9 TWO DEGREE COMPATIBILITY

All transmissions of the VIASAT-3 satellite network will not exceed the uplink off-axis EIRP
density and downlink PFD levels of §25.138, regardless of whether the frequency band used is
subject to §25.138.

A.9.1 Frequency Bands Subject to §25.138

For those frequency bands subject to §25.138, compliance with the Commission’s two-degree
spacing policy is ensured provided:

1) The uplink off-axis EIRP density levels of §25.138(a)(1) of the Rules for blanket
licensing are not exceeded;

2) The maximum PFD levels are lower than the PFD values given in §25.138(a)(6) of the
Rules.

The clear sky uplink off-axis EIRP density limits of §25.138(a)(1) are equivalent to a maximum
uplink input power density of -56.5 dBW/Hz, assuming the transmitting earth station meets the off-
axis gain mask requirements of § 25.209(a) and (b). Table 9-1 compares the uplink input power

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densities derived from the uplink link budgets that are contained in the Schedule S form with the
clear sky limits of §25.138 (a)(1) of the Rules. 1 It can be seen that in all cases the clear sky uplink
power limits are met. No authorized uplink transmissions towards the VIASAT-3 satellite will
exceed the clear sky uplink off-axis EIRP density limits of §25.138(a)(1).

Table A.9-1. Demonstration of Compliance with the Uplink Power Limits of §25.138(a)(1)
(assuming the transmitting earth station antenna meets the off-axis gain mask requirements
of §25.209(a) and (b))
Clear Sky Uplink
Maximum Clear
Input Power
Uplink Antenna Sky Uplink Input Excess Margin
Emission Density Limit of
Size Power Density (dB)
§25.138 (a)(1)
(dBW/Hz)
(dBW/Hz)
67 cm 6M25G7D -63.5 -56.5 7.0
67 cm 3M13G7D -60.5 -56.5 4.0
67 cm 1M57G7D -57.5 -56.5 1.0
67 cm 782KG7D -56.6 -56.5 0.1
7.3 m 25M0G7D -71.3 -56.5 14.8
7.3 m 500MG7D -76.9 -56.5 20.4

Further, Section A.8 above demonstrates that the maximum PFD that could be transmitted by the
VIASAT-3 satellite, at a 90° elevation angle, is -122.1 dBW/m2/MHz and therefore the PFD
levels at other elevation angles will necessarily be somewhat lower. No downlink transmissions
from the VIASAT-3 satellite will exceed the -118 dBW/m2/MHz limit set forth in §25.138 (a)(6)
of the Rules.

1
In cases where a transmitting earth station does not meet the off-axis gain mask requirements of §25.209(a) and
(b), the maximum input power density into the antenna will be correspondingly reduced such that off-axis EIRP
density requirements of §25.138(a)(1) are still met.

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A.9.2 Frequency Bands Not Subject to §25.138

This section demonstrates that uplink transmissions in the 28.1-28.35 GHz and 28.6-29.1 GHz
bands and downlink transmissions in the 18.8-19.3 GHz band are two-degree compatible.

28.1-28.35 GHz Band:

Currently there are no operational GSO Ka-band satellites that use the 28.1-28.35 GHz band at or
within two degrees of the 79.3º W.L. location, nor are there any pending applications before the
Commission for use of the band by a GSO satellite at or within two degrees of 79.3° W.L.
Therefore, in order to demonstrate two-degree compatibility, the transmission parameters of the
VIASAT-3 satellite have been assumed as both the wanted and victim transmissions.

Since the uplink input power densities for both the wanted and victim carriers are assumed to be
identical, the uplink C/I is simply the difference between the on-axis gain and the off-axis gain.
The uplink C/I ratio is calculated as follows:

(C/I)up = Gmax - (29-25*log(θ))

= 64.9 - (29-25*log(2)) = 43.4 dB

The calculated C/I ratio is quite large and therefore clearly demonstrates two-degree compatibility.

28.6-29.1 GHz and 18.8-19.3 GHz Bands:

Hughes Network Systems, LLC (“Hughes”) has Commission-authorization to operate the
JUPITER 77W satellite at the 77.3° W.L. orbital location and to use the 28.6-29.1 GHz and 18.8-

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19.3 GHz bands. 2 Table A.9-2 provides a summary of the uplink and downlink transmission
parameters of the JUPITER 77W satellite network, as taken from Hughes’ LOA application.

Table A.9-3 provides a summary of the uplink and downlink transmission parameters of the
VIASAT-3 satellite network. These parameters were derived from the VIASAT-3 link budgets
that are embedded in the associated Schedule S form.

Interference calculations were performed using the transmission parameters in Tables A.9-2 and
A.9-3. The interference calculations assumed a 1 dB advantage for topocentric-to-geocentric
conversion, all wanted and interfering carriers are co-polarized and all earth station antennas
conform to a sidelobe pattern of 29-25 log(θ). The C/I calculations were performed on a per Hz
basis.

Tables A.9-4 and A.9-5 show the results of the interference calculations between the two
networks in terms of C/I margins. It can be seen that the C/I margins are positive in all cases.

Note that the JUPITER 77W satellite network’s return links (i.e., subscriber-to-gateway links) do
not use the uplink 28.6-29.1 GHz band. Accordingly, the C/I calculations for certain
interferer/victim carrier combinations only calculate the downlink interference. The grayed cells
in Tables A.9-4 and A.9-5 are overall C/I margins (i.e., combined uplink and downlink C/I
margins), while the non-grayed cells are downlink C/I margins only.

2
See SAT- LOA-20111223-00248.

9

Table A.9-2. JUPITER 77W transmission parameters.
Tx E/S Uplink Rx E/S
Emission Bandwidth Downlink EIRP C/I Criterion
Carrier ID Gain EIRP Gain
Designator (MHz) (dBW) (dB)
(dBi) (dBW) (dBi)
1 250MG7W 250 58.9 72.0 64.0 42.1 21.5
2 3M67G7W 3.67 N/A N/A 43.7 55.3 20.4
3 1M22G7W 1.22 N/A N/A 38.8 55.3 19.3
4 612KG7W 0.612 N/A N/A 35.8 55.3 18.7

Table A.9-3. VIASAT-3 transmission parameters.
Tx E/S Uplink Rx E/S
Emission Bandwidth Downlink EIRP C/I Criterion
Carrier ID Gain EIRP Gain
Designator (MHz) (dBW) (dB)
(dBi) (dBW) (dBi)
5 500MG7D 500 64.9 75.0 62.0 49.7 20.3
6 500MG7D 500 64.9 75.0 62.0 41.1 13.6
7 500MG7D 500 64.9 75.0 62.0 41.1 7.2
8 6M25G7D 6.25 44.4 48.9 39.2 61.5 16.2
9 3M13G7D 3.125 44.4 48.9 36.2 61.5 14.9
10 1M57G7D 1.563 44.4 48.9 33.1 61.5 9.9
11 782KG7D 0.7813 44.4 46.7 30.1 61.5 8.7
12 25M0G7D 25 64.5 67.2 45.2 60.8 20.8

Table A.9-4. Summary of the C/I margins (dB); VIASAT-3 interfering into JUPITER 77W.
Interfering Carriers
Carrier ID 5 6 7 8 9 10 11 12
1 5.1 5.1 5.1 6.2 4.6 2.5 1.8 8.4
Carriers
Wanted

2 17.5 17.5 17.5 21.3 21.3 21.3 21.3 21.3
3 18.6 18.6 18.6 22.4 22.4 22.4 22.4 22.4
4 19.2 19.2 19.2 23.0 23.0 23.0 23.0 23.0

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Table A.9-5. Summary of the C/I margins (dB); JUPITER 77W interfering into VIASAT-3.
Interfering Carriers
Carrier ID 1 2 3 4
5 3.8 6.0 6.0 6.0
6 2.1 4.0 4.1 4.1
Wanted Carriers

7 8.4 10.4 10.4 10.4
8 12.5 18.0 18.0 18.0
9 15.3 19.3 19.4 19.4
10 21.2 24.3 24.4 24.4
11 22.6 25.6 25.6 25.6
12 10.5 12.8 12.8 12.8

A.10 SHARING WITH LMDS AND WITH SECONDARY FSS IN THE 28.1-28.35
GHZ BAND

In the U.S., the 28.1-28.35 GHz band is allocated to LMDS on a primary basis and it is allocated
to the FSS on a secondary basis. §2.105(c)(2) states, in part, that stations of a secondary service:

(i) Shall not cause harmful interference to stations of primary services to which
frequencies are already assigned or to which frequencies may be assigned at a later date;

(ii) Cannot claim protection from harmful interference from stations of a primary
service to which frequencies are already assigned or may be assigned at a later date;

Regarding §2.105(c)(2)(i), uplinks from gateway-type earth stations that are located in the
United States must be operated in a manner such that they do not cause harmful interference to
any current or future licensed LMDS station. Technical compatibility will be accomplished
through geographic separation between the gateway-type antennas and the LMDS stations and
shielding as necessary. Regarding §2.105(c)(2)(ii), transmitting LMDS stations cannot cause
harmful interference into an earth station since the earth station does not receive transmissions in
the 28.1-28.35 GHz band. Harmful interference occurring from the aggregation of transmitting
LMDS stations into a receiving spot beam of the VIASAT-3 satellite is considered to be

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unlikely, however ViaSat undertakes to accept this risk and will not seek protection from such
interference in the event it occurs.

The antennas deployed in this band segment will operate in the A-Type Spot Beams and the B-
Type Spot Beams. The locations for these antennas have not yet been selected.

The applications for those earth stations using the 28.1-28.35 GHz band within the U.S. will
include an appropriate demonstration that the proposed operations will not cause harmful
interference into any licensed LMDS station. The earth station licensee will take appropriate
actions to protect any future licensed LMDS station that has the potential to receive harmful
interference, including ceasing transmissions in the 28.1-28.35 GHz band if necessary.

Currently there are no operational NGSO systems authorized by the Commission to use the 28.1-
28.35 GHz band, nor are there any pending applications before the Commission for use of the
28.1-28.35 GHz band by a NGSO system. O3b Limited (“O3b”) has received a license from the
Commission for a gateway earth station located in Hawaii to communicate with O3b’s
constellation of NGSO satellites using the 28.1-28.35 GHz band on a secondary basis. 3 The
analysis in the following section regarding the compatibility of VIASAT-3 operations in the
United States with those authorized operations of that O3b gateway in the 28.6-29.1 GHz and
18.8-19.3 GHz bands is equally applicable to the 28.1-28.35 GHz band segment.

A.11 SHARING WITH NGSO FSS IN THE 28.6-29.1 GHZ AND 18.8-19.3 GHZ BANDS

In the United States, the 28.6-29.1 GHz band is allocated to NGSO FSS on a primary basis and it
is allocated to GSO FSS on a secondary basis. Stations operating in a secondary service cannot
cause harmful interference to or claim protection from harmful interference from stations of a
primary service. ViaSat’s proposed U.S. operations will be consistent with the obligations of a

3
See SES-LIC-20100723-00952.

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secondary user of spectrum to avoid harmful interference into, and to accept any interference
received from, primary users.

The highest interference levels that could occur into NGSO networks from the VIASAT-3
network are when there is an “in-line” event. On the uplink for example, an in-line event occurs
when the NGSO satellite, the GSO satellite and the interfering GSO earth station are all in a line.
As the NGSO satellite continues to move within its orbit, an angle between the NGSO satellite
and the GSO satellite, subtended at the GSO earth station, is created. As long as the GSO earth
station does not transmit when the NGSO satellite is within a certain angle, no harmful
interference to the NGSO satellite will occur. A similar situation exists on the downlink. The
amount of angular separation required will be dependent on the parameters of the NGSO FSS
networks, their earth station locations, and their interference criteria.

O3b has received a license from the Commission for a gateway earth station located in Hawaii
authorized to communicate with O3b’s constellation of NGSO satellites using the 28.6-29.1 GHz
and 18.8-19.3 GHz bands. 4 Interference analysis provided herein demonstrates that no harmful
interference will occur between O3b’s gateway operations in Hawaii, and the operations of the
VIASAT-3 satellite network in the United States.

Currently there are no NGSO satellite networks authorized by the Commission to use the 28.6-
29.1 GHz and 18.8-19.3 GHz bands. Northrop Grumman Space and Mission Systems Corp.
(“Northrop Grumman”) had previously received Commission authorization for its Global EHF
Satellite Network (“GESN”) and ATCONTACT Communications, LLC (“ATCONTACT”) had
previously received Commission authorization for its NGSO network. Both networks were to
utilize highly elliptical orbits (“HEO”). The interference analysis contained herein demonstrates
that the operations of the VIASAT-3 satellite network would protect HEO satellite systems with

4
See SES-LIC-20100723-00952.

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the characteristics of those previously licensed to ATCONTACT and NGST from harmful
interference.

A.11.1 Compatibility with O3b

O3b has Commission authorization to communicate with its NGSO network using a gateway
earth station located in Hawaii. The following analysis addresses compatibility of VIASAT-3
operations in the United States with that O3b earth station. The O3b constellation will use eight
satellites in a medium earth orbit with an altitude of 8062 km and an inclination of zero degrees
(i.e., an equatorial orbit). The satellites have steerable spot beams which are maintained on the
gateway location as the satellites traverse their orbit until a minimum elevation angle is no longer
met. Table A.11-1 shows the pertinent parameters of the VIASAT-3 network and the O3b
system.

Table A.11-1. Summary of VIASAT-3 and O3b parameters.
Parameters VIASAT-3 O3b System
Minimum Operational Elevation Angle 3°
Earth Station Uplink Input Power Density -56.6 dBW/Hz -53.4 dBW/Hz
Satellite Rx Antenna Gain 53.2 dBi 34.5 dBi
Satellite Rx System Noise Temp 1349 K 1000 K
Satellite Tx EIRP Density -20 dBW/Hz -28.32 dBW/Hz
Earth Station Rx System Noise Temperature 224 K 225 K

The minimum elevation angle for service to the Hawaiian gateway is stated as being 3 degrees.
From this we can determine the eastern-most location of an O3b satellite, just before it can no
longer communicate with the Hawaiian gateway, as being at 99.67° W.L. This orbital location
provides the smallest angular separation with respect to the VIASAT-3 network. Any location of
an O3b satellite further west will necessarily create a larger angular separation with respect to the
VIASAT-3 network.

The O3b system has an equatorial orbit. From the perspective of sharing with a GSO network,
this means that the location of a GSO network’s transmitting earth station that causes the most

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interference to the O3b system would be a location closest to the equator, or in the case of the
VIASAT-3 network, an earth station located at a southerly location. Similarly, a GSO network’s
receiving ground antenna located closest to the equator would receive the most interference from
the O3b system. Of course, in both cases, the location of the O3b gateway antenna also plays a
role in the mutual interference environment.

For interference calculation purposes, the location of the VIASAT-3 earth station antenna was
chosen to be both southerly and westerly (within CONUS) since it was found that such a location
causes a higher potential for a mutual interference environment.

Given these antenna locations and with the O3b satellite assumed to be at a static 99.67° W.L.
location, the angular separation (off-axis angle) at the relevant earth station can be calculated. In
addition, the calculations take into account the fact that the VIASAT-3 satellite provides at least
20 dB of satellite antenna discrimination towards Hawaii in both uplink and downlink directions
and the O3b satellites communicating with the Hawaiian gateway provide at least 20 dB of
satellite antenna discrimination towards the service area of the VIASAT-3 satellite network in
both uplink and downlink directions.

Table A.11-2 shows the predicted interference degradations to the O3b system due to operation
of the VIASAT-3 network and vice versa. The results show that the O3b system is adequately
protected. The calculated ΔT/T values in all cases are extremely small, indicating the technical
compatibility of the VIASAT-3 satellite network with the authorized operation of the O3b
gateway in Hawaii.

The preceding demonstrates that the VIASAT-3 satellite network is compatible with O3b’s
authorized operations of a gateway earth station located in Hawaii.

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Table A.11-2. Interference calculations between VIASAT-3 and O3b (Hawaii).
Victim network O3b (Hawaii) VIASAT-3
Interfering network VIASAT-3 O3b (Hawaii)

E/S Latitude degrees 21.67 34.5
E/S Longitude degrees -158.03 -120.5

Uplink:
Frequency band GHz 28.85 28.85
Interfering uplink input power density dBW/Hz -56.6 -53.4
Angular separation between interfering E/S and victim satellite degrees 20.6 7.1
Slant range (Interfering path) km 10359 41483
Free space path loss (Interfering path) dB 202.0 214.0
Atmospheric losses dB 1.2 1.2
Victim satellite receive antenna gain dBi 34.5 53.2
Victim Satellite's Antenna Discrimination towards Interfering E/S dB 20 20
Victim satellite Rx system noise temperature K 1000 1349
No dBW/Hz -198.6 -197.3
Io dBW/Hz -246.1 -227.4
Io/No dB -47.5 -30.1
∆T/T % 0.0018 0.0972

Downlink:
Frequency band GHz 19.05 19.05
Interfering satellite downlink EIRP density dBW/Hz -20.0 -28.32
Slant range (Interfering path) dB 41483 10359
Free space path loss (Interfering path) dB 210.4 198.3
Atmospheric & scintillation losses dB 1 1
Angular separation between interfering satellite and victim E/S degrees 7.1 20.6
Interfering Satellite's Antenna Discrimination towards Victim E/S dB 20 20
Victim Rx earth station system noise temperature K 225 224
No dBW/Hz -205.1 -205.1
Io dBW/Hz -243.4 -248.5
Io/No dB -38.3 -43.4
∆T/T % 0.0147 0.0046

A.11.2 Sharing with HEO Systems

This section analyzes compatibility of VIASAT-3 with HEO systems. Table A.11-3 summarizes
the salient parameters of the GESN and ATCONTACT HEO satellite networks. These
parameters are identical to those used by Northrop Grumman and ATCONTACT to demonstrate
independently that their GSO operations in the 28.6-29.1 GHz and 18.8-19.3 GHz bands were
compatible with the other’s proposed NGSO operations. 5 It can be seen that the two networks’

5
See SAT-AMD-20040719-00138 and SAT-AMD-20040719-00141.
16

orbital and transmission parameters are identical, which allows a single interference analysis to
be performed.

Table A.11-3. GESN and ATCONTACT HEO satellite characteristics.

GESN ATCONTACT
Orbital parameters
• # of satellites 3 3
• # of planes 3 3
• # of satellites per plane 1 1
• Inclination 63.4° 63.4°
• Apogee 39352 km 39352 km
• Perigee 1111 km 1111 km
16000 km 16000 km
• Minimum Tx altitude
Satellite Rx gain 46.5 dBi 46.5 dBi
Satellite Rx system noise temp. 504 K 504 K
Earth station uplink input power density -63.45 dBW/Hz -63.45 dBW/Hz
Satellite downlink EIRP density -18 dBW/Hz -18 dBW/Hz
E/S Rx system noise temperature 315 K 315 K

In order to demonstrate compatibility with these two NGSO networks, a worst case, static
interference analysis is performed. The smallest possible angle will occur when the GSO
satellite, the NGSO satellite and the relevant earth station are all on the same longitude and the
earth station is at a high latitude. Assuming a minimum 10° elevation angle for the GSO earth
station, this sets the latitude to 71.4°N. The GESN and ATCONTACT satellites would not
transmit when they are at an altitude below 16000 km, which translates to a latitude of 31.9°N.
With this information, the smallest possible angular separation is then calculated to be 27.4
degrees. Both the transmitting GSO earth station (uplink calculation) and the victim NGSO
earth station (downlink calculation) have been assumed to be at a latitude of 71.4°N.

Table A.11-4 shows the results of interference calculations from the VIASAT-3 network into the
GESN and ATCONTACT networks and vice versa. The calculated ΔT/T values in all cases are
very small, indicating the technical compatibility of the VIASAT-3 satellite network with the
GESN and ATCONTACT networks.

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The compatibility of these networks is largely due to the fact that the two NGSO networks do not
communicate with earth stations when their satellites cross the equatorial plane, thus in-line
events with a GSO network do not occur. For other types of NGSO constellations that do
communicate with earth stations when the satellites pass through the equatorial plane, it is
possible that an in-line interference event could occur. In order to protect such systems, ViaSat
will cease transmissions from the VIASAT-3 satellite and its associated earth stations such that
the required amount of angular separation with the NGSO network is always maintained.

Table A.11-4. Worst case interference calculations.

Victim network GESN / ATCONTACT VIASAT-3
Interfering network VIASAT-3 GESN / ATCONTACT

Uplink:
Frequency band GHz 29 29
Interfering uplink input power density dBW/Hz -56.6 -63.45
Angular separation degrees 27.4 27.4
Slant range (Interfering path) km 21046 40586
Space loss (Interfering path) dB 208.2 213.9
Atmospheric & scintillation losses dB 1.2 1.2
Victim satellite receive antenna gain dBi 46.5 53.2
Victim satellite Rx system noise temperature K 504 1349
No dBW/Hz -201.6 -197.3
Io dBW/Hz -226.4 -232.3
Io/No dB -24.9 -35.0
∆T/T % 0.3260 0.0317

Downlink:
Frequency band GHz 19 19
Interfering satellite downlink EIRP density dBW/Hz -20.0 -18
Slant range (Interfering path) dB 40586 21046
Space loss (Interfering path) dB 210.2 204.5
Atmospheric & scintillation losses dB 1 1
Angular separation degrees 27.4 27.4
Victim Rx earth station system noise temperature K 315 224
No dBW/Hz -203.6 -205.1
Io dBW/Hz -238.2 -230.5
Io/No dB -34.6 -25.4
∆T/T % 0.0350 0.2893

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A.12 ORBITAL DEBRIS MITIGATION PLAN

The spacecraft manufacturer for the VIASAT-3 satellite has not yet been selected and therefore
ViaSat’s Orbital Debris Mitigation Plan is necessarily forward looking. ViaSat will incorporate
the material objectives of §25.114(d)(14) of the Commission’s Rules into the design of the
satellite through the satellite’s Technical Specifications, Statement of Work and Test Plans. The
Statement of Work will include provisions to review orbital debris mitigation as part of the
preliminary design review (“PDR”) and the critical design review (“CDR”) and to incorporate its
requirements, as appropriate, into its Test Plan, including a formal Failure Mode Verification
Analysis (“FMVA”) for orbital debris mitigation involving particularly the TT&C, propulsion
and energy systems. During this process, some changes to the Orbital Debris Mitigation Plan
may occur and ViaSat will provide the Commission with updated information, as appropriate.

A.12.1 Spacecraft Hardware Design

Although the VIASAT-3 satellite has not been fully designed, ViaSat does not expect that the
satellite will undergo any release of debris during its operation. Furthermore, all separation and
deployment mechanisms, and any other potential source of debris are expected to be retained by
the spacecraft or launch vehicle.

ViaSat will assess and limit the probability of the satellite becoming a source of debris by
collisions with small debris or meteoroids of less than one centimeter in diameter that could
cause loss of control and prevent post-mission disposal. ViaSat will take steps to limit the
effects of such collisions through shielding, the placement of components, and the use of
redundant systems. ViaSat will incorporate a rugged TT&C system with regard to meteoroids
smaller than 1 cm through redundancy, shielding, separation of components and physical
characteristics. The VIASAT-3 satellite will include two near omni-directional antennas
mounted on opposite sides of the spacecraft. These antennas will be extremely rugged and
capable of providing adequate coverage even if struck, bent or otherwise damaged by a small or
medium sized particle. ViaSat plans to locate the command receivers and decoders and

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telemetry encoders and transmitters within a shielded area and provide redundancy and physical
separation for each component. The VIASAT-3 satellite will carry a rugged propulsion system
capable of withstanding collision with small debris.

A.12.2 Minimizing Accidental Explosions

ViaSat and its spacecraft manufacturer will assess and limit the probability of accidental
explosions during and after completion of mission operations. The satellite will be designed to
ensure that debris generation will not result from the conversion of energy sources on board the
satellite into energy that fragments the satellite. The propulsion subsystem pressure vessels will
be designed with high safety margins. Bipropellant mixing is prevented by the use of valves that
prevent backwards flow in propellant lines and pressurization lines. All pressures, including
those of the batteries, will be monitored by telemetry. At end-of-life and once the satellite has
been placed into its final disposal orbit, ViaSat will remove all stored energy from the spacecraft
by depleting any residual fuel, leaving all fuel line valves open, venting the pressure vessels and
the batteries will be left in a permanent state of discharge.

A.12.3 Safe Flight Profiles

In considering current and planned satellites that may have a station-keeping volume that
overlaps the VIASAT-3 satellite, ViaSat has reviewed the lists of FCC licensed satellite
networks, as well as those that are currently under consideration by the FCC. In addition,
networks for which a request for coordination has been published by the ITU within ±0.15° of
79.3° W.L. have also been reviewed.

Based on these reviews, there are no operational satellites within ±0.15 ° 0f 79.3° W.L., there are
no pending applications before the Commission to use an orbital location within ±0.15° of 79.3°
W.L and there are no published ITU networks within ±0.15° of 79.3° W.L. Accordingly, ViaSat
concludes that physical coordination of the VIASAT-3 satellite with another party is not required
at the present time.

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A.12.4 Post-Mission Disposal

At the end of the operational life of the VIASAT-3 satellite, ViaSat will maneuver the satellite to
a disposal orbit with a minimum perigee of 300 km above the normal GSO operational orbit.
The post-mission disposal orbit altitude is based on the following calculation, according to
§25.283:

Total Solar Pressure Area “A” = 105.1 m2
“M” = Dry Mass of Satellite = 3168 kg
“CR” = Solar Pressure Radiation Coefficient = 1.9

Therefore the Minimum Disposal Orbit Perigee Altitude:

= 36,021 km + 1000 x CR x A/m
= 36,021 km + 1000 x 1.9 x 105.1/3168
= 36,084 km
= 298 km above GSO (35,786 km)

Adequate margin has already been accounted for in the calculation of the disposal orbit of 300
km. This will require 11 kg of propellant that will be reserved, taking account of all fuel
measurement uncertainties, to perform the final orbit raising maneuver.

A.13 PREDICTED RECEIVER AND TRANSMITTER CHANNEL FILTER
RESPONSE CHARACTERISTICS

The predicted receiver and transmitter frequency responses of each 500 MHz or 1000 MHz
channel, as measured between the receive antenna input and transmit antenna, fall within the
limits shown in Table A.13-1 below. In addition, the frequency tolerances of §25.202(e) and the
out-of-band emission limits of §25.202(f) (1), (2) and (3) will be met.

21

Table A.13-1: Predicted Channel Receiver and Transmitter Frequency Responses

Frequency Receiver Frequency Receiver Frequency Transmit Frequency Transmit Frequency
Rx/Tx (MHz) Response (dB) Response (dB) Response (dB) Response (dB)

(without NGSO) (with NGSO) (without NGSO) (with NGSO)

28000/18200 <-20.0 <-20.0 <-20.0 <-20.0

28100/18300 > -3.0 >-3.0 >-3.0 >-3.0

28200/18400 > -1.7 >-2.0 >-1.5 >-1.5

28300/18500 > -1.5 >-1.7 >-0.75 >-0.75

28400/18600 >-1.5 >-1.5 >-0.5 >-0.5

28500/18700 >-1.7 >-1.5 >-0.5 >-0.5

28600/18800 >-3.0 >-1.5 >-0.5 >-0.5

28700/18900 <-20.0 >-1.5 >-0.5 >-0.5

28800/19000 <-20.0 >-1.5 >-0.5 >-0.5

28900/19100 <-20.0 >-1.7 >-0.5 >-0.5

29000/19200 <-20.0 >-2.0 >-0.5 >-0.5

29100/19300 <-20.0 >-3.0 >-0.5 >-0.5

29200/19400 <-20.0 <-20.0 N/A N/A

29300/19500 <-20.0 <-20.0 N/A N/A

29400/19600 <-20.0 <-20.0 N/A N/A

29500/19700 >-3.0 <-20.0 >-0.5 >-0.5

29600/19800 >-1.7 <-20.0 >-0.5 >-0.5

29700/19900 >-1.5 <-20.0 >-0.5 >-0.5

29800/20000 >-1.5 <-20.0 >-0.75 >-0.75

29900/20100 >-1.7 <-20.0 >-1.5 >-1.5

30000/20200 >-3.0 <-20.0 >-3.0 >-3.0

30100/20300 <-20.0 <-20.0 <-20.0 <-20.0

Note: “N/A” indicates that transmit frequency response is not applicable because signal is
attenuated by the input frequency response.

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services that the satellite will provide. The link budgets are sufficiently robust to compensate for
the negligible degradation caused by the slightly reduced cross-polarization isolation
performance. Grant of the requested waiver is also consistent with prior Commission decisions
granting similar waivers of Section 25.210(i). 7

__________________________________

7
See, e.g., ViaSat, Inc., File Nos. SAT-LOI-20080107-00006, SAT-AMD-20080623-00131,
SAT-AMD-20090213-00023, Call Sign S2747, Attachment – Conditions for Letter of Intent
at ¶ 5 (granted Aug. 18, 2009).

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CERTIFICATION OF PERSON RESPONSIBLE FOR PREPARING
ENGINEERING INFORMATION

I hereby certify that I am the technically qualified person responsible for preparation of

the engineering information contained in this pleading, that I am familiar with Part 25 of the

Commission’s rules that I have either prepared or reviewed the engineering information

submitted in this pleading, and that it is complete and accurate to the best of my knowledge and

belief.

/s/
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Stephen D. McNeil
Telecomm Strategies Canada, Inc.
Ottawa, Ontario, Canada
(613) 270-1177

25

Document Created: 2013-03-15 16:13:00
Document Modified: 2013-03-15 16:13:00

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