Attachment Attachment A SAT-LOA-20190617-00048

Attachment Attachment A

This document pretains to SAT-LOA-20190617-00048 for Application to Launch and Operate on a Satellite Space Stations filing.

IBFS_SATLOA2019061700048_1737837

ATTACHMENT A
Technical Information to Supplement Schedule S

A.1 SCOPE AND PURPOSE

Viasat, Inc. (“Viasat”) has U.S. market access to operate the VIASAT-3 satellite at 88.9° W.L. under
authority of the United Kingdom. Specifically, Viasat has been granted U.S. market access to
provide FSS services using the 28.1-29.1 GHz and 29.5-30 GHz band segments (Earth-to-space) and
the 18.3-19.3 GHz and 19.7-20.2 GHz band segments (space-to-Earth). Viasat now seeks U.S.
market access for that spacecraft in the 27.5-28.1 GHz and 29.1-29.5 GHz band segments (Earth-to-
space) and the 17.7-18.3 GHz and 19.3-19.7 GHz band segments (space-to-Earth).

In addition, Viasat seeks to modify its existing VIASAT-3 U.S. market access for the 29.5-30 GHz
and 19.7-20.2 GHz bands so that Viasat instead may be licensed in those band segments as a U.S.
operator at 88.9° W.L. and implement VIASAT-3 under the USASAT-31S ITU satellite network
currently implemented through the Ka band payload on Galaxy 28. For purposes of this attachment,
the 29.5-30 GHz band and 19.7-20.2 GHz payload will be known as “VIASAT-89US”. The
remainder of the satellite’s payload, including that portion used for TT&C, will be known as
“VIASAT-3 (89W).” Both payloads will be on the same spacecraft.

There is no change to the coverage of the United States underlying the current U.S. market access
grant, but the satellite’s coverage area now includes visible earth. Viasat will now use portions of
the conventional Ku-band for TT&C and conduct TT&C operations from outside the United States.
The coverage of the United States does not change, nor are there changes in any of the fundamental
RF characteristics that would affect the operating environment with other spectrum users.1

1
Although not directly related to the existing terms of the market access grant for 88.9º W.L., Viasat notes that
the satellite to be deployed will now provide near-hemispheric coverage.

1

The purpose of this Attachment is to provide the Commission with the technical characteristics of
the VIASAT-3 (89W) payload, as modified to include the 27.5-28.1 GHz and 29.1-29.5 GHz band
segments (Earth-to-space) and the 17.7-18.3 GHz and 19.3-19.7 GHz bands (space-to-Earth), as well
as those of the VIASAT-89US payload for the 29.5-30 GHz (Earth-to-space) and 19.7-20.2 GHz
(space-to-Earth) band segments.2

A.2 GENERAL DESCRIPTION

The satellite will provide a variety of Ka-band satellite services from the nominal 89º W.L. orbital
location, with an offset of 0.1° and the station-keeping box centered at 88.9° W.L.

The satellite network will provide service to small, fixed and temporary-fixed user antennas as
well as to very small antennas for earth stations in motion (ESIM) applications. In addition,
gateway-type antennas called satellite access nodes (SANs) will be employed.

The satellite’s beam coverage, both transmit and receive, consists of multiple spot beams that
collectively are capable of providing service to virtually all parts of the Earth visible from 88.9°
W.L. This application seeks authority with respect to CONUS, Hawaii, Puerto Rico, the U.S.
Virgin Islands and parts of Alaska (i.e., all portions of the United States and its territories that are
visible from 88.9° W.L.).

The satellite typically uses asymmetric forward (SAN-to-subscriber) and return (subscriber-to-
SAN) links. The network uses adaptive coding and modulation to combat rain fades. That is, the

2
The spacecraft will be capable of operating across the 27.5-31.0 GHz band (Earth-to-space) and the 17.7-21.2
GHz band (space-to-Earth), but this application seeks Commission authority only with respect to the 27.5-28.1
GHz, 29.1-29.5 GHz, 17.7-18.3 GHz, and 19.3-19.7 GHz band segments, which represent the additional bands
being added to the existing Commission authority, and the request to operate in the 19.7-20.2 GHz and 29.5-30
GHz band segments under a U.S. license instead of under the current U.S. market access grant. The technical
information being provided in this application relates only to these bands.

2

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).

As noted above, TT&C operations will be conducted from outside the United States in the Ku-
band and thus are not the subject of this application.

A.3 FREQUENCY AND POLARIZATION PLAN

The satellite’s frequency plan for which Commission authorization is sought is given in Table A.3-
1, indicating channel center, polarization and bandwidth. The table also shows the connectivity
between each uplink and downlink band. Circular polarization is used on both the uplink and
downlink with the downlink polarization being orthogonal to the uplink polarization. The satellite
re-uses the spectrum such that any channel is re-used multiple times by a combination of polarization
and spatial isolation. This satisfies the requirements of §25.210(f) of the FCC’s Part 25 rules (the
“Rules”).

Table A.3-1. Satellite’s Frequency Plan for Additional Frequencies and VIASAT-US89
Uplink
Downlink
Band
Uplink Band Center Downlink Bandwidth
Payload Center
Polarization Frequency Polarization (MHz)
Frequency
(MHz)
(MHz)
VIASAT-3 (89W) 27,800 RHCP, LHCP 18,000 LHCP, RHCP 600
VIASAT-3 (89W) 29,300 RHCP, LHCP 19,500 LHCP, RHCP 400
VIASAT-US89 29,750 RHCP, LHCP 19,950 LHCP, RHCP 500

A.4 SATELLITE ANTENNA BEAMS AND ANTENNA GAIN CONTOURS

The satellite’s antenna gain contours are being provided to the Commission in a GIMS container
file; one file for each of the two payloads.

Each payload employs multiple spot beams in both the uplink and downlink directions. There are
two types of spot beams: small beams (“A”-type beams) and larger beams (“B”-type beams). For
each beam-type, the beams are nominally identical.

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Viasat is providing the Commission with an isoline gain contour, in both uplink and downlink
directions, that depict, on a composite basis across the entire coverage area, the -2 dB relative gain
contour of all spot beams that may be operated within that area. In addition, the predicted antenna
gain contours for one transmit and receive representative spot beam for each of the two beam types,
and in both polarizations, is included in the two GIMS files associated with the individual
VIASAT-3 (89W) and VIASAT-89US payloads.

The following beams have been included in the GIMS file associated with the VIASAT-3 (89W)
payload:

1) RAR1, RAR2, RAL1 and RAL2. Representative spot beam contours for the uplink A-type
beams, in both polarizations, and for each uplink band.
2) TAR1, TAR2, TAL1 and TAL2. Representative spot beam contours for the downlink A-
type beams, in both polarizations, and for each downlink band.
3) RBR1, RBR2, RBL1 and RBL2. Representative spot beam contours for the uplink B-type
beams, in both polarizations, and for each uplink band.
4) TBR1, TBR2, TBL1 and TBL2. Representative spot beam contours for the downlink B-
type beams, in both polarizations, and for each downlink band.
5) RXAR_ISO and RXAL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the uplink A-type beams; applicable to both uplink bands.
6) TXAR_ISO and TXAL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the downlink A-type beams; applicable to both downlink bands.
7) RXBR_ISO and RXBL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the uplink B-type beams; applicable to both uplink bands.
8) TXBR_ISO and TXBL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the downlink B-type beams; applicable to both downlink bands.

The following beams have been included in the GIMS file associated with the VIASAT-89US
payload:

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1) RAR1 and RAL1. Representative spot beam contours for the uplink A-type beams in both
polarizations.
2) TAR1and TAL1. Representative spot beam contours for the downlink A-type beams in
both polarizations.
3) RBR1 and RBL1. Representative spot beam contours for the uplink B-type beams in both
polarizations.
4) TBR1 and TBL1. Representative spot beam contours for the downlink B-type beams in
both polarizations.
5) RXAR_ISO and RXAL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the uplink A-type beams.
6) TXAR_ISO and TXAL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the downlink A-type beams.
7) RXBR_ISO and RXBL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the uplink B-type beams.
8) TXBR_ISO and TXBL_ISO. These contain a -2 dB relative gain isoline contour, in both
polarizations, for the downlink B-type beams.

A.5 TT&C CHARACTERISTICS

TT&C operations will be conducted from outside the United States in the conventional Ku-band
and thus are not the subject of this application. As information, the TT&C center frequencies
available to be used by the spacecraft are given in Table A.5-1.

Table A.5-1. Summary of the TT&C Subsystem Characteristics

Usage Frequency (MHz) Polarization
14000.3 Vertical
14001.0 Vertical
Command
14498.5 Horizontal
14499.0 Horizontal

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11700.25 Horizontal or Vertical
11701.75 Horizontal or Vertical
Telemetry
12197.5 Horizontal or Vertical
12199.5 Horizontal or Vertical

Intelsat operates the C-/Ku-/Ka-band GALAXY 28 satellite at 89° W.L. Viasat has coordinated
its proposed use of these TT&C frequencies with Intelsat.

A.6 MAXIMUM KA-BAND TRANSMISSION LEVELS

The satellite network will be operated such that the maximum uplink and downlink transmissions,
from and to the United States, will not exceed the transmission levels contained in §25.138,
regardless of the Ka-band frequency band segment. Authorized uplink transmissions to the
satellite will not exceed the applicable EIRP density envelopes of §25.138(a). The satellite’s
downlink transmissions will not exceed a PFD level of -118 dBW/m2/MHz. Because PFD is
dependent on the slant path and hence spreading loss, the maximum EIRP density from the satellite
can vary accordingly. For example, for a spreading loss of 162.8 dB (25° elevation angle), the
satellite’s transmissions would not exceed an EIRP density of 44.8 dBW/MHz.

A.7 POWER FLUX DENSITY AT THE EARTH’S SURFACE (17.7-18.3 GHZ AND
19.3-19.7 GHZ BANDS)

The maximum PFD transmitted towards U.S. territory by the VIASAT-3 (89W) payload will be
compliant with the §25.208(c) PFD limits that apply to the 17.7-18.3 GHz and 19.3-19.7 GHz bands.
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.

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As explained in section A.6, Viasat will operate the satellite such that no transmissions in any
downlink Ka-band frequency band segment will exceed a PFD level of -118 dBW/m2/MHz towards
U.S. territory. This PFD level is in compliance with §25.208(c).

A.8 TWO DEGREE COMPATIBILITY

A.8.1 Frequency Bands Subject to §25.138

Viasat certifies that authorized uplink transmissions to the VIASAT-89US payload will not exceed
the applicable EIRP density envelopes of §25.138(a) and that payload’s downlink transmissions
will not exceed a PFD level of -118 dBW/m2/MHz. Similarly, Viasat also certifies that authorized
uplink transmissions to the VIASAT-3 (89W) payload will not exceed the applicable EIRP density
envelopes of §25.138(a) and that the payload’s downlink transmissions will not exceed a PFD
level of -118 dBW/m2/MHz. Accordingly, two-degree compatibility is ensured for the 29.25-30
GHz and 19.7-20.2 GHz band segments.

A.8.2 Frequency Bands Not Subject to §25.138

This section demonstrates that transmissions in the 27.5-28.1 GHz and 29.1-29.25 GHz band
segments (Earth-to-space) and the 17.7-18.3 GHz and 19.3-19.7 GHz band segments (space-to-
Earth) are two-degree compatible. Currently there are no operational GSO Ka-band satellites that
use these bands at or within two degrees of the 88.9º W.L. location, nor are there any pending
applications before the Commission for use of these bands by a GSO satellite at or within two degrees
of 88.9° W.L. Therefore, in order to demonstrate two-degree compatibility, the transmission
parameters of the VIASAT-3 (89W) payload have been assumed as both the wanted and victim
transmissions.

Table A.8-2 provides a summary of the typical uplink and downlink transmission parameters of
the VIASAT-3 (89W) payload and which were used in the interference analysis. The interference
calculations assumed a 1 dB advantage for topocentric-to-geocentric conversion and that all
wanted and interfering carriers are co-polarized. The C/I calculations were performed on a per Hz
basis.

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Table A.8-3 shows the results of the interference calculations in terms of the overall C/I margins.
It can be seen that the C/I margins are positive in all cases, demonstrating that transmissions
associated with the VIASAT-3 (89W) payload are two-degree compatible.

Table A.8-2. Typical VIASAT-3 payload transmission parameters.
Assigned Tx E/S Uplink Rx E/S
Emission Downlink EIRP C/I Criterion
Carrier ID Bandwidth Gain EIRP Gain
Designator (dBW) (dB)
(MHz) (dBi) (dBW) (dBi)
1 600MG7D 600 65.0 75.0 70.8 49.3 19.7
2 500MG7D 500 65.0 75.0 70.0 49.3 20.5
3 500MG7D 500 65.0 75.0 70.0 40.7 13.8
4 500MG7D 500 65.0 75.0 70.0 33.7 9.3
5 400MG7D 400 65.0 75.0 69.0 40.7 14.7
6 300MG7D 300 65.0 75.0 67.8 40.7 9.6
7 200MG7D 200 44.3 58.3 63.0 61.4 14.0
8 100MG7D 100 44.3 57.7 60.0 61.4 13.3
9 50M0G7D 50 44.3 57.1 57.0 61.4 11.3
10 12M5G7D 12.5 44.3 55.4 51.0 61.4 11.9
11 6M25G7D 6.25 37.3 39.1 48.0 61.4 9.3

Table A.8-3. Summary of the overall C/I margins (dB).
Interfering Carriers
Carrier
1 2 3 4 5 6 7 8 9 10 11
ID
1 9.0 9.0 9.0 9.0 9.0 8.9 10.7 9.9 8.7 5.8 5.6
2 8.3 8.3 8.3 8.3 8.2 8.2 10.1 9.4 8.3 5.6 5.4
3 6.5 6.5 6.5 6.5 6.4 6.4 9.3 9.1 8.9 8.1 8.0
Wanted Carriers

4 4.0 4.0 4.0 4.0 4.0 3.9 6.9 6.9 6.8 6.6 6.6
5 5.5 5.5 5.5 5.5 5.5 5.5 8.3 8.2 8.0 7.3 7.3
6 10.6 10.6 10.6 10.6 10.6 10.6 13.5 13.4 13.3 12.7 12.7
7 17.5 16.9 16.9 16.9 16.1 15.0 9.8 7.3 5.0 0.6 0.3
8 19.9 19.4 19.4 19.4 18.7 17.7 12.8 10.4 8.1 3.8 3.4
9 23.3 22.9 22.9 22.9 22.3 21.5 17.1 14.7 12.4 8.1 7.8
10 24.6 24.3 24.3 24.3 24.0 23.5 20.5 18.3 16.1 11.9 11.5
11 16.5 16.0 16.0 16.0 15.4 14.6 10.2 7.8 5.5 1.2 0.8

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A.9 SHARING WITH TERRESTRIAL SERVICES IN THE 27.5-28.35 GHZ BAND

In the U.S., the 27.5-28.35 GHz band is designated for the Upper Microwave Flexible Use
(UMFU) Service and FSS is generally secondary to UMFUS, although a transmitting earth
station in the 27.5-28.35 GHz band that meets the criteria in §25.136(a) may be authorized on an
interference-protected basis.

Applications for earth station antennas communicating with the VIASAT-3 (89W) payload and
using the 27.5-28.35 GHz band segment within the U.S. will include an appropriate
demonstration that the proposed operations will be in compliance with §25.136, or otherwise
would operate on a secondary basis.

A.10 SHARING WITH NGSO MSS FEEDER LINKS IN THE 29.1-29.3 GHZ AND 19.4-
19.6 GHZ BANDS

Currently, Iridium is the only licensed MSS Feeder Link operator in the U.S. and is authorized to
operate feeder links in the 29.1-29.3 GHz and 19.4-19.6 GHz bands. Viasat is seeking coordination
with Iridium and has performed an interference analysis for operation of Earth-to-space and space-
to-Earth links in the 29.1-29.3 GHz and 19.4-19.6 GHz bands which are shared with NGSO MSS
Feeder Links. The analysis considers the Iridium system characteristics as Notified in the
HIBLEO-2FL and HIBLEO-2FL2 ITU filings.

Table A.10-1 HIBLEO-2FL2 Parameters

Parameter / Description Value
Satellites 66 with orbital characteristic per HIBLEO-
2FL filing
Orbital planes / satellites per plane 6 planes / 11 satellites per plane
Orbital height 780 km
Orbital inclination 86.4°
Orbital period 100 min
Feeder link frequency (uplink) 29.1-29.3 GHz

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Feeder link frequency (downlink) 19.4-19.6 GHz
Feeder link polarization (uplink) RHCP
Feeder link polarization (downlink) RHCP
Satellite FL beam receive antenna gain 30.1 dBi
Satellite FL beam antenna pattern S.465
Satellite FL beam receive system noise 1295 K
Satellite FL beam G/T (calculated) -1.02 dB/K
Feeder link emission designator 4M38Q7W
Earth station tracking scheme Tracking based on longest hold time with 5°
minimum elevation at earth station
Tracked earth station Tempe, AZ
Earth station receive gain 53.2 dBi
Earth station receive system noise 731 K

The Iridium MSS Feeder Link uses right hand circular polarization (RHCP) for both the Earth-to-
space and space-to-Earth links. VIASAT-3 (89W) uses both right hand circular and left hand
circular polarization (LHCP) for its Earth-to-space and space-to-Earth beams.

Until coordination has been concluded with Iridium, in the downlink space-to-Earth direction
(19.4-19.6 GHz band), Viasat will avoid co-frequency co-polar operations of Type A RHCP beams
with boresights centered with an azimuth and/or elevation of less than 0.73 degrees from the
azimuth and elevation of the Tempe, AZ gateway. In the case of RHCP Type B beams operating
co-frequency with Iridium, the minimum offset for beam center azimuth and/or elevation will be
0.95 degrees the with respect to the boresight azimuth/elevation for the Tempe gateway.

Visualyse analyses were performed which show that the resulting I/N would be less than -12.2 dB
more than 99.999% of the time in each of these scenarios.

Similar analyses were performed in the space-to-Earth direction for the left hand circular polarized
beams which are operating cross-polarized from the Iridium system. In this case the required
azimuth/elevation offset for beam center pointing of either the Type A beam or the Type B beam,
with respect to the beam center pointing for the Tempe, AZ Feeder Link gateway, is less than for
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the co-polarized case. Any offset greater than 0.3 degrees for the Type A beam and 0.5 degrees for
the Type B beam are sufficient to reduce the I/N at the Iridium gateway to less than -12.2 dB for
more than 99.999% of the time.

This can also be easily calculated by working from the assumption that the maximum downlink
pfd at Tempe is -118 dB(W/(m2*MHz)) in the right hand polarization then applying the cross-pol
isolation value between the RHC and LHC polarizations and then solving for downlink pfd. The
resulting value is ~15 dB above the value that would result in a -12.2 dB I/N. The required offset
can then be taken from the gain roll-off in the downlink beam pattern such that any pointing angle
of beam center for the LHCP downlink beam greater than that value will reduce the downlink
e.i.r.p. density by more than 15 dB.

Figure A.10-1 Type A beam interference into Feeder Link Rx (space-to-Earth)

Type A beam I/N into FL Rx
100

10

1

0.1
Time (%)

0.01

0.001

0.0001

0.00001
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0
I/N (dB)

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Figure A.10-2 Type B beam interference into Feeder Link Rx (space-to-Earth)

Type B beam I/N into FL Rx
100

10

1

0.1
Time (%)

0.01

0.001

0.0001

0.00001
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0
I/N (dB)

Applications for earth station antennas communicating with the VIASAT-3 (89W) payload and
using the 29.1-29.25 GHz band segment within the U.S. will include an appropriate
demonstration that the proposed operations, either have been coordinated with, or will otherwise
be compatible with Iridium and will operate on a secondary basis.

A.11 SHARING WITH NGSO FSS IN THE 27.5-28.1 GHZ AND 17.8-18.3 GHZ BANDS

The Commission and the ITU have adopted identical epfd↑ and epfd↓ limits applicable to NGSO
systems operating in the 27.5-28.1 GHz and 17.8-18.3 GHz bands, respectively. In the ITU
regulatory regime, NGSO FSS systems are secondary to GSO FSS networks in these bands. The
purpose for the development of the ITU epfd limits was to protect primary GSO networks, while
increasing the use of the spectrum by allowing NGSO systems to use the same bands. The primary
mechanism employed by NGSO systems in order to adhere to the epfd limits is to cease
transmissions when some minimum separation angle towards the geostationary arc occurs (i.e., an
“exclusion zone”). The exclusion zone ensures protection to GSO networks, including Viasat’s
GSO network, from NGSO system interference, in both uplink and downlink directions, and
simultaneously protects NGSO systems from interference due to GSO networks.
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A.14 SHARING WITH FSS SATELLITE NETWORKS (EARTH-TO-SPACE) IN
THE 17.7-17.8 GHZ BAND SEGMENT

In the U.S., the 17.7-17.8 GHz band segment is allocated in the Earth-to-space direction to the
FSS. In this band, FSS is limited to feeder links for the broadcasting-satellite service (“BSS”).

A.14.1 Space Path Interference

A space station transmitting in the space-to-Earth direction in the 17.7-17.8 GHz band segment
has the potential to cause interference into a space station receiving Earth-to-space transmissions
in the same band (i.e., space path interference due to bi-directional usage). The Commission has
examined the potential for such interference in the context of sharing between 17/24 GHz BSS
satellite networks and BSS feeder links.3 The requirements to facilitate 17/24 GHz BSS operation
anywhere within the 17.3-17.8 GHz band are codified in §25.264.

In accordance with §25.264(a), Annex 1 to this Attachment provides predicted off-axis gain
information in the X-Z plane over a range of ± 30 degrees from the negative and positive X-axes,
for both the A-type beams and B-type beams, in both polarizations, in planes rotated from the X-
Z plane about the Z-axis over a range of ± 60 degrees relative to the equatorial plane, and at a
center frequency of 17.775 GHz. §25.264(a)(4) seeks antenna off-axis gain information at three
different frequencies: 17.735 GHz, 17.55 GHz and 17.775 GHz. The requirement to provide off-
axis gain information at these three frequencies assumes the applicant transmits across the entire
17.3-17.8 GHz band, which is not the case for the VIASAT-3 (89W) payload, since it only
transmits in the upper 17.7-17.8 GHz band. By providing predicted off-axis gain measurements

3
See Establishment of Policies and Service Rules for the Broadcasting-Satellite Service at the 17.3-17.7 GHz
Frequency Band and at the 17.7-17.8 GHz Frequency Band Internationally, and at the 24.75-25.25 GHz
Frequency Band for Fixed Satellite Services Providing Feeder Links to the Broadcasting-Satellite Service and
for the Satellite Services Operating Bi-directionally in the 17.3-17.8 GHz Frequency Band, Second Report and
Order, 26 FCC Rcd 8927 (2011).

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and not adequately shielded. Given that Viasat’s operations in the 17.7-17.8 GHz band segment
would be on a non-conforming, unprotected basis, Viasat accepts this risk.

A.15 ORBITAL DEBRIS MITIGATION PLAN

The VIASAT-3 (89W) payload and the VIASAT-US89 payload will be on the same spacecraft. For
purposes of simplicity in describing Viasat’s orbital debris mitigation plan, we refer generally to
Viasat’s satellite, or spacecraft, containing both payloads.

A.15.1 Spacecraft Hardware Design

The satellite is based on the flight proven Boeing 702 HP and MP heritage platform. The following
updated orbital debris mitigation plan takes into account the selected spacecraft bus.

Viasat has assessed and limited the amount of debris released in a planned manner during normal
operations. The satellite has been designed so as to not become a source of debris during launch,
drift, or operating mode. All separation and deployment mechanisms, and any other potential
source of debris, are expected to be retained by the spacecraft or launch vehicle.

In conjunction with the satellite manufacturer, Viasat has assessed and limited 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 and the satellite manufacturer have taken steps to limit the effects of such
collisions through shielding, the placement of components, and the use of redundant systems.

The satellite includes redundant TT&C, bus control electronics and propulsion subsystems to
ensure successful end-of-life disposal. The spacecraft TT&C system, vital for orbit raising, will
be extremely rugged with regard to meteoroids smaller than 1 cm, by virtue of its redundancy,
shielding, separation of components and physical characteristics. The TT&C subsystem will have
no single points of failure. Near-omni-directional antenna coverage is provided through the use
of a combination of independent bicone and forward/aft pipe antennas. These antenna feeds are
extremely rugged and capable of providing adequate coverage even if struck, bent or otherwise

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damaged by a small or medium sized particle. The command receivers and decoders and telemetry
encoders and transmitters will be located within a shielded area and will be totally redundant and
physically separated. The Xenon tank, shielded in the spacecraft structure central cylinder, and a
redundant pair of thrusters provide the energy for orbit-raising.

A.15.2 Minimizing Accidental Explosions

In conjunction with the satellite manufacturer, Viasat has assessed and limited the probability of
accidental explosions during and after completion of mission operations through a failure mode
verification analysis. The satellite manufacturer has taken steps to ensure that debris generation
will not result from the conversion of energy sources on board the satellite into energy that
fragments the satellite. All vessel pressures and battery cell voltages 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 and leaving the
batteries in a permanent state of discharge. The xenon tank is vented by opening latch valves
downstream of the tank to allow cold flow through the xenon ion thrusters, and the latch valve is
open if negligible xenon remains. Otherwise, the xenon latch valves may remain closed. There is
no liquid propulsion system on the spacecraft.

A.15.3 Safe Flight Profiles

Viasat’s existing market access provides for the satellite to be located at 88.9º W.L. Viasat does
not seek to change this location in this application.

A.15.4 Post-Mission Disposal

There is no change to the originally planned post-mission disposal orbit altitude of 300 km above
the normal GSO operational orbit, which was based on the following analysis and calculation
under §25.283:

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Total Solar Pressure Area “A” = 220 m2
“M” = Dry Mass of Satellite = 5000 kg
“CR” = Solar Pressure Radiation Coefficient = 1.147

Therefore, the Minimum Disposal Orbit Perigee Altitude:

= 36,021 km + 1000 x CR x A/m
= 36,021 km + 1000 x 1.147 x 220/5000
= 36,061 km
= 286 km above GSO (35,786 km)

To provide adequate margin, increasing the disposal orbit to 300 km will require 1.7 kg of xenon
propellant, taking account of all fuel measurement uncertainties, which will be allocated and
reserved in order to perform the final orbit raising maneuver.

__________________________________

18

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
TSCI
Ottawa, Ontario, Canada
(613) 270-1177

19

ANNEX 1

This annex provides eight predicted off-axis gain pattern cuts for the VIASAT-3 (89W) payload in
the X-Z plane over a range of ± 30 degrees from the negative and positive X-axes, for both the A-
type beams and B-type beams, in both polarizations, in planes rotated from the X-Z plane about the
Z-axis over a range of ± 60 degrees relative to the equatorial plane, and at a center frequency of
17.775 GHz.

Document Created: 2019-06-17 14:49:15
Document Modified: 2019-06-17 14:49:15

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