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BSS-601 (JCSat 3) [Boeing]

BSS-601HP (MEASAT 3) [Boeing BSS]

BSS-601MEO (ICO) [Boeing BSS]

The body-stabilized Boeing 601 satellite is the best-selling large spacecraft model in the world. Eighty-one orders for the spacecraft had been received by January 2002.

The Boeing 601 was introduced in 1987 to meet anticipated requirements for high-power, multiple-payload satellites for such applications as direct television broadcasting to small receiving antennas, very small aperture terminals for private business networks, and mobile communications. The basic configuration features as many as 48 transponders and offers up to 4,800 watts.

A more powerful version, the Boeing 601HP, made its debut in 1995. The HP versions can carry payloads twice as powerful as the classic Boeing 601 models, through such innovations as gallium arsenide solar cells, advanced battery technology, and an optional xenon ion propulsion system (XIPS). The 601HP features as many as 60 transponders and provides up to 10,000 watts.

The 601MEO version is a medium orbit version, designed for direct placement of the satellites into orbit by the launch vehicle, which allows for the simplification of the standard BSS-601 propulsion system.

All Boeing 601 spacecraft use the same basic bus design, enabling Boeing Satellite Systems to realize efficiencies gained by production volume, tooling investments and quantity buys.

The Boeing 601 body is composed of two modules:

• the primary structure that carries all launch vehicle loads and contains the propulsion subsystem, bus electronics, and battery packs; and
• a structure of honeycomb shelves that hold the communications equipment, electronics, and isothermal heat pipes.

Reflectors, antenna feeds, and solar arrays mount directly to the payload module, and antenna configurations can be placed on three faces of the bus. This modular approach allows work to proceed in parallel, thereby shortening the manufacturing schedule and test time.

Failures

Following failures of 601 models have occured:

• Asiasat 3 (HGS 1): batteries problems - partial performance loss during eclipses
• DirecTV 1: 1998 - spacecraft control processor (SCP) failure - no service loss
• DirecTV 1: 2002 - spacecraft control processor (SCP) failure - no service loss
• Galaxy 3R: 2001 - spacecraft control processor (SCP) failure - no service loss; 2006 - back-up spacecraft control processor (SCP) failure - removed from service
• Galaxy 4: 1998 - spacecraft control processors (SCP) failures - total loss
• Galaxy 4R: 2003 - primary and secondary XIPS failure - lifetime shortened
• Galaxy 7: 1998, 2000 - spacecraft control processors (SCP) failures - total loss 2000
• Galaxy 8i: primary and secondary XIPS failure - lifetime shortened
• Galaxy 10R: lost both its primary and its secondary XIPS system in August 2004 - probably reducing the remaining life to 3 years.
• JCSar 1B (5); experienced an anomaly in one of its thrusters- temporary loss of services - 17. January 2005.
• M-Sat 1: failureof two power amplifiers - partial loss
• Palapa C1: Battery Charge Controller failed: service loss during eclipses
• PAS 4: spacecraft control processor (SCP) failure - no service loss
• PAS 5: 1998 - battery problems - partial loss
• PAS 6B: 2003 - primary and secondary XIPS failure - lifetime shortened
• Solidaridad 1: 1999, 2000 - spacecraft control processors (SCP) failures - total loss 2000
• Superbird 6 (A2): one of two main fuel tanks lost pressure on November 28 - lifetime significantly shortened
• TDRS 8: problems with multi-access antenna
• TDRS 9: partial tank pressure loss after launch

References

• Boeing BSS 601 Factsheet