Orbital GEOStar-3 Bus User Manual

GEO

Satellite Bus

GEOStar™-3 Bus

A Fully Redundant Spacecraft Bus Designed for Geosynchronous Missions

FACTS AT A GLANCE

Design

The GEOStar-3 satellite platform represents an evolutionary growth of Orbital's GEOStar-2 platform,

providing an incremental expansion of the ight-proven GEOStar-2 product line. EPS enhancements

include an increase in battery capacity and in solar array power, enabling GEOStar-3 to provide up

to 8,000 watts of power to the payload at end-of-life. The larger solar arrays and additional battery

capacity retain the 100 percent successful ight heritage 36 volt regulated power bus. The GEOStar-3

Bus structure’s mass carrying capability and propellant tank accommodation enable optimal use of

launch vehicle performance, and can include tandem launch missions that use heritage bi-propellant

apogee engines to ensure fast and reliable orbit raising. For heavier missions, a ight proven Electric

Propulsion system will replace the heritage ImpEHTs for stationkeeping operations.

Payload Accommodations

The GEOStar-3 Bus can accommodate payloads of up to 800 kilograms and 8,000 watts. As many as

72 radiatively cooled TWTAs, or a greater combination of radiatively and conductively cooled TWTAs can

easily be accommodated on the platform. The total payload conductive thermal dissipation is scalable up

to 4,800 watts. The platform can accommodate a broad range of depoyable reectors and nadir antenna

congurations, enabling compelling payload solutions. The expanded payload envelope of GEOStar-3 also

allows customers to consider a larger universe of hosted payload opportunities.

• Increased power system capability to

provide 8 kW of payload power

• Structure accommodates up to 800 kg

payload mass and 4.8 kW payload

conducted thermal dissipation

• Compatibility with all commercially

available launch vehicles allowing

greater exibility and lower launch cost

• Ability to dual manifest two spacecraft

as a tandem launch on select launch

vehicles

• Incorporation of ight-proven, low-risk

components

• Congure-to-order exibility to

optimize customer value

Tandem Launch Conguration

GEOStar™-3 Bus

Specications

Core Bus Features

Payload Mass Capability: Up to 800 kg (single)

Orbit: Geosynchronous

Typical Mission Lifetime: >15 years

Delivery: 24 months after receipt of

order (payload dependent)

Single Launch

Compatibility: Ariane 5, Falcon 9, H-IIA,

Proton, Sea Launch, Land
Launch

Dual Launch

Compatibility: Ariane 5, Proton, Falcon

Heavy

Structure

Bus Dimensions (HxWxL):

3.0 to 3.9 m* x 2.1 m x 2.3 m

Construction: Composite/Al

Power Subsystem

Payload Power: 8,000 W

Bus Voltage: 36 VDC (nominal)

Solar Arrays: Multi-junction GaAs cells

Batteries: Li-Ion

Attitude Control Subsystem

Stability Mode: 3-axis; zero momentum

Propulsion Subsystem

Transfer Orbit System: Liquid bi-propellant

On Orbit: Electric + Monopropellant

Command & Data Handling Subsystem

Flight Processor: BAE RAD750

Interface Architecture: MIL-STD 1553B, CCSDS

*Extensible payload module height

More Information

Mr. Amer Khouri

Vice President of Marketing, Global Communications

[phone], [e-mail]

Low Cost Launch Opportunities

The GEOStar-3 Bus is designed to maintain compatibility with all commercially

available launch vehicles. The ability to launch on multiple vehicles gives customers

greater exibility and lower launch cost access to space. The propellant tanks

on GEOStar-3 support a larger delta-V to orbit than typical GEO satellites, which

allows GEOStar-3 to make optimal use of launch vehicle performance capability.

In addition, GEOStar-3 adds the opportunity to dual-manifest two spacecraft

on select launch vehicles, with each spacecraft congured to fulll its mission

independently after launch. This creates an opportunity for dramatic launch

cost savings. Whether designed for a single-launch or dual-launch campaign,

GEOStar-3 offers a signicant increase in payload mass capability.

Mission Services

Customers can purchase a GEOStar-3 spacecraft bus alone, or as part of a turn-

key service that includes an integrated satellite, operations and launch vehicle.

Orbital conducts spacecraft commissioning from its own ground station prior to

transferring spacecraft control to the customer’s operations center.

Mission Life

As with the GEOStar-2, the GEOStar-3 satellite is designed with conservative

margin beyond 15 years, taking into account damaging effects of the

geosynchronous environment. The typical limitation of mission duration is on-board

fuel for orbit maintenance station-keeping. Fuel life can be optimized and extended

to well over 15 years, based on launch vehicle selection. Orbital has several

delivered satellites with predicted fuel life in excess of 20 years. GEOStar-3 has

propellant accommodation that can be used to signicantly extend maneuver life.

Heritage and Versatility

GEOStar-3 was designed around the concept of scalability and customer options,

while still maintaining the use of standardized, qualied components and subsystems.

The C&DH system of the GEOStar family has been upgraded to provide more

capability to support advanced mission requirements. The EPS system of the

GEOStar family, while retaining the heritage 36V regulated bus architecture, offers

expandable capability to support GEOStar-3 class payload power requirements. The

dual-manifest launch capability introduced with GEOStar-3 uses the same highly

reliable, short duration bi-propellant orbit raise propulsion system that has enjoyed

success on over 30 GEOStar-2 spacecraft. GEOStar-3 has options for battery and

solar array size, payload module height and station-keeping thruster selection that

allow Orbital to provide customers with the best balance of satellite and launch

cost, mission lifetime and payload performance. With its expanded payload carrying

capability, enhanced C&DH functionality and larger EPS system, GEOStar-3 also

offers customers the largest hosted payload envelope in the GEOStar family.

Value

GEOStar-3 further enhances Orbital’s value proposition to its customers,

combining fast delivery, low cost and high reliability with a larger payload envelope

and low cost launch alternatives.

Orbital Sciences Corporation

45101 Warp Drive

©2014 Orbital Sciences Corporation FS002_13_2998

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Dulles, Virginia 20166

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www.orbital.com