The high specific impulse reduced the propellant requirements, versus chemical systems, by 300 kg to 400 kg, thus allowing incorporation of more communications hardware aboard the spacecraft or reduction in launch size and cost. The ion propulsion system consisted of two fully redundant strings each consisting of two thrusters and one power processing unit. Two daily burns of 5 hours each were generally required for the north-south station-keeping function. Typical spacecraft lifetime was about 15 years. Approximate masses for a thruster and power processing unit were 5.0 kg and 6.8 kg, respectively. Overall ion propulsion system dry mass for the spacecraft was about 68 kg. The power processing unit contained seven power modules for the beam, accelerator, discharge, two keepers discharges, and two heaters. Overall power processing unit efficiency was 88%. PanAmSat was Hughes' first customer for the XIPS-13 propulsion system on PAS-5. This was was launched August 27, 1997.
The development of the 18mN Xenon ion thruster subsystem for telecom satellites could also have use in low force thrusters for attitude control. The XIPS comprised four 13 cm thrusters (two primary and two back-up) with power supply. Each thruster had 439 W input off 29.34 Vdc, and a propellant storage and control unit. The total XIPS system mass was 68 kg. The Hughes Company stated that the system was developed from work on a 25 cm dia x 63.5 cm thruster that provided Isp of 2800 secs at 1.3 kW input.. Manufacturer: Hughes Research Laboratories. Thrust: 17.8mN. Beam Voltage: 751 V. Accelerator Voltage: -300 V. Beam Current: 0.405 A. Accelerator Current: 0.97 mA. Exhaust Velocity: 30 km/sec. Isp: 2585 sec. Beam Power: 304 W. Power/Thrust Ratio: 24.6 W/mN. Electrical Efficiency: 51.3%. Mass: 5.0 kg each thruster (x4). 6.8 kg each power processor (x4). 2.0 kg each Xe tank (x2).
Electrical Input Power: 1.30 kW. Engine: 68 kg (149 lb). Thrust to Weight Ratio: 0.
Status: In Production.
Unfuelled mass: 68 kg (149 lb).
Diameter: 0.26 m (0.85 ft).
Thrust: 0.0178 N (0.0040 lbf).
Specific impulse: 2,585 s.